Journal articles: 'Antibacterial Assay'

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Peternel, Luka, Miha Kotnik, Andrej Preželj, and Uroš Urleb. "Comparison of 3 Cytotoxicity Screening Assays and Their Application to the Selection of Novel Antibacterial Hits." Journal of Biomolecular Screening 14, no. 2 (February 2009): 142–50. http://dx.doi.org/10.1177/1087057108329452.

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Cytotoxicity screening of new chemical entities in antibacterial drug discovery discerns between cytotoxic and antimicrobial activity, thus providing predictive evidence for selective toxicity. The objective of this study was to evaluate 3 cytotoxicity assays in identifying novel antibacterial hits with desired safety margins. The endpoints in assays comprised adenylate kinase (AK) release rate as an indicator of membrane rupture (Toxilight™), intracellular adenosine triphosphate (CellTiter-Glo™), and reduction of resazurin (CellTiter-Blue™) both as indicators of cell metabolic activity. In the CellTiter-Glo™ and the CellTiter-Blue™ assays, 7 of 8 selected compounds showed cytotoxicity, whereas in the Toxilight™ assay, 3 of 8 compounds significantly reduced cell viability in the ChoK1 and the JurkatE6.1 cell line. The CellTiter-Glo™ assay proved to be the most sensitive among the evaluated assays, and excellent Z′ values were obtained in the 96-well plate (Z′ > 0.83). The CellTiter-Glo™ assay was clearly superior to the CellTiter-Blue™ and the Toxilight™ assay for the initial cytotoxicity screening. Moreover, the application of the CellTiter-Glo™ assay to determine mammalian cell toxicity versus the antibacterial effect ratio contributed to early identification of antibacterial hits with desired safety margins. The chemical structures of these novel antibacterial hits are disclosed herein. ( Journal of Biomolecular Screening 2009:142-150)

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Akbar, Noor, Ruqaiyyah Siddiqui, Mazhar Iqbal, and Naveed Ahmed Khan. "Antibacterial Activities of Selected Pure Compounds Isolated from Gut Bacteria of Animals Living in Polluted Environments." Antibiotics 9, no. 4 (April 17, 2020): 190. http://dx.doi.org/10.3390/antibiotics9040190.

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Antibiotic resistance is a global threat to public health, further accelerated by the misuse of antibiotics in humans and animals. Our recent studies have shown that gut bacteria of animals living in polluted environments are a potential source of antibacterials. Gut bacteria of cockroaches, water monitor lizards and the turtle exhibited molecules such as curcumenol, docosanedioic acid, N-acyl-homoserine lactone, L-homotyrosine and Di-rhamnolipids. Using purified compounds, assays were performed to determine their antibacterial properties using serial dilution method, cytotoxic effects using lactate dehydrogenase release, and cell viability using MTT assay. The results revealed that the purified compounds exhibited significant antibacterial activities (p < 0.05) against selected Gram-negative (Pseudomonas aeruginosa) and Gram-positive bacteria (Streptococcus pyogenes) with effective MIC50 and MIC90 at µg concentrations, and with minimal effects on human cells as observed from LDH and MTT assays. These findings are significant and provide a basis for the rational development of therapeutic antibacterials. Future studies are needed to determine in vivo effects of the identified molecules together with their mode of action, which could lead to the development of novel antibacterial(s).

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Prastiyanto, Muhammad Evy, Inas Hasna Azizah, Hafizha Dara Haqi, Bagus Dwi Yulianto, Aulia Bella Agmala, Zhafira Dias Radipasari, Nita Ayu Dwi Astuti, and Arifani Rahma Putri. "In-vitro antibacterial activity of the seed extract of three-member Artocarpus towards Methicillin-Resistant Staphylococcus aureus (MRSA)." Jurnal Teknologi Laboratorium 9, no. 2 (December 31, 2020): 128–35. http://dx.doi.org/10.29238/teknolabjournal.v9i2.237.

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Methicillin-Resistant Staphylococcus aureus (MRSA) infections have created a critical need for the development of natural antibacterials from a biological source. This research aimed to investigate the antibacterial activity of the seed extract of three-member Artocarpus (Artocarpus heterophyllus, A. champeden, and A. camansi) against MRSA which are the most prevalent causes of infections in patients. Crude seed extracts of three-member Artocarpus were evaluated for their antibacterial activity against MRSA. The antibacterial activity against MRSA of the three extracts was assayed in vitro by the agar well diffusion assay and agar microdilution method and minimum bactericidal concentration. The antibacterial activity, calculated as a zone of inhibition and MIC, MBC values. The Crude seed extracts of three-member Artocarpus showed antibacterial activity against the MRSA in the agar well diffusion assay (1.5-9 mm inhibition diameter). The MIC value of extract showed at 15.62 mg/mL and the MBC value of seed extract of A. heterophyllus at 62.5 mg/mL, A. champeden at 31.25 mg/mL, A. camansi at 250 mg/mL. All seed extracts have the potential to be developed as antibacterial agents, particularly against MRSA strain. Studies on the antibacterial activity against MRSA can provide new information about the benefits seed of members of Artocarpus as a source of natural antibacterial.

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Sawai, J., R. Doi, Y. Maekawa, T. Yoshikawa, and H. Kojima. "Indirect conductimetric assay of antibacterial activities." Journal of Industrial Microbiology & Biotechnology 29, no. 5 (November 2002): 296–98. http://dx.doi.org/10.1038/sj/jim/7000314.

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Sawai, J., R. Doi, Y. Maekawa, T. Yoshikawa, and H. Kojima. "Indirect conductimetric assay of antibacterial activities." Journal of Industrial Microbiology and Biotechnology 29, no. 5 (November 1, 2002): 296–98. http://dx.doi.org/10.1038/sj.jim.7000314.

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Ivanenkov, Yan A., Renat S. Yamidanov, Ilya A. Osterman, Petr V. Sergiev, Vladimir A. Aladinskiy, Anastasia V. Aladinskaya, Victor A. Terentiev, et al. "Identification of N-Substituted Triazolo-azetidines as Novel Antibacterials using pDualrep2 HTS Platform." Combinatorial Chemistry & High Throughput Screening 22, no. 5 (August 8, 2019): 346–54. http://dx.doi.org/10.2174/1386207322666190412165316.

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Aim and Objective: Antibiotic resistance is a serious constraint to the development of new effective antibacterials. Therefore, the discovery of the new antibacterials remains one of the main challenges in modern medicinal chemistry. This study was undertaken to identify novel molecules with antibacterial activity. Materials and Methods: Using our unique double-reporter system, in-house large-scale HTS campaign was conducted for the identification of antibacterial potency of small-molecule compounds. The construction allows us to visually assess the underlying mechanism of action. After the initial HTS and rescreen procedure, luciferase assay, C14-test, determination of MIC value and PrestoBlue test were carried out. Results: HTS rounds and rescreen campaign have revealed the antibacterial activity of a series of Nsubstituted triazolo-azetidines and their isosteric derivatives that has not been reported previously. Primary hit-molecule demonstrated a MIC value of 12.5 µg/mL against E. coli Δ tolC with signs of translation blockage and no SOS-response. Translation inhibition (26%, luciferase assay) was achieved at high concentrations up to 160 µg/mL, while no activity was found using C14-test. The compound did not demonstrate cytotoxicity in the PrestoBlue assay against a panel of eukaryotic cells. Within a series of direct structural analogues bearing the same or bioisosteric scaffold, compound 2 was found to have an improved antibacterial potency (MIC=6.25 µg/mL) close to Erythromycin (MIC=2.5-5 µg/mL) against the same strain. In contrast to the parent hit, this compound was more active and selective, and provided a robust IP position. Conclusion: N-substituted triazolo-azetidine scaffold may be used as a versatile starting point for the development of novel active and selective antibacterial compounds.

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N, Asmathunisha. "Rapid Method for Detecting Bactericidal Effects of Mangrove Derived Silver Nanoparticles Using Resazurin Microdilution Assay." International Journal for Research in Applied Science and Engineering Technology 9, no. 8 (August 31, 2021): 2438–42. http://dx.doi.org/10.22214/ijraset.2021.37784.

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Abstract: Nanoparticles plays a vital role in the field of antimicrobial agents against pathogenic microorganisms. Screening of nanoparticles for antimicrobial activities is a time consuming and cumbersome process. Recently, a simple technique of using the dye resazurin has been used as an indicator of bacterial growth for testing antimicrobial activity on microtitre plate. However, this technique does not quantify the microbial load. Therefore, the present work was attempted to find a new antibacterial method employing the dye resazurin assay and haemocytometric counting of microbes for testing silver nanoparticles synthesised from Xylocarpus mekongensis .The bacterial strains E. coli, S. aureus and P. aeruginosa (multi-drug resistant strain) were used to evaluate the screening of mangrove extracts. Minimum inhibition concentration (MIC) was also calculated for the silver nanoparticles using ciproflaxcin as reference antibiotic. The antibacterial activity Xylocarpus mekongensis was carried out against all the three bacteria by the same method and the values were compared with reference antibiotic. The present study has suggested a rapid, dependable, easy and inexpensive method, suitable for testing the antibacterial activity of silver nanoparticles which are promising to develop as new antibacterials. Keywords: Mangroves, Silver, Nanoparticles, Resazurin, Antibacterials

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Park, Chung-Mu, and Hyun-Seo Yoon. "Antibacterial Activity of Litsea cubeba (May Chang) Essential Oil Against Streptococcus mutans and Porphyromonas gingivalis." Korean Society of Oral Health Science 11, no. 2 (June 30, 2023): 67–73. http://dx.doi.org/10.33615/jkohs.2023.11.2.67.

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Objectives: This study analyzed the antibacterial effects of Litsea cubeba essential oil (LCEO) against both Streptococcus mutans and Porphyromonas gingivalis, as well as inhibitory effect on biofilm formation. Methods: Antibacterial activity of LCEO was analyzed by minimum inhibition concentration on bacterial growth, disk diffusion and growth inhibitory assays. In addition, growth inhibitory effect of LCEO was also evaluated by biofilm formation assay. Results: LCEO significantly inhibited growth of S. mutans and P. gingivalis in a dose dependent manner. In addition, these results were coincided with the result of biofilm formation assay. Conclusions: LCEO exhibited potent antibacterial activity against both pathogens, which provides that LCEO might be used as a potential candidate for oral healthcare supplies.

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Shi, Danxia, Wenliang Xu, Marie Wong, and David G. Popovich. "An Improved Purification Method for Removing Colour Interference from 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyl Tetrazolium Bromide (MTT) Antibacterial Assays." Applied Sciences 13, no. 8 (April 18, 2023): 5067. http://dx.doi.org/10.3390/app13085067.

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The MTT antibacterial assay is an important method in natural antibacterial component discovery. Researchers can use the MTT antibacterial assay to quickly and efficiently evaluate the antibacterial activity of natural compounds. The aim of this research was to find a method to reduce background colour and bacterial cell interference when using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay to study the antibacterial effect of phytochemicals. This study used NZ ‘Hass’ ripe avocado seed extract as an example to develop a silica gel column chromatography method that could combine with the MTT assay to remove the background colour and bacterial cells before the formazan measuring stage. This method is particularly suitable for MTT-based antibacterial inhibition studies when the tested phytochemical extracts have an interfering colour.

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Srusti S. N. R, Prathibha K. Y, and Keshamma E. "Assay of Antibacterial Activity of Gymnema sylvestre Extracts." international journal of engineering technology and management sciences 6, no. 5 (September 28, 2022): 847–51. http://dx.doi.org/10.46647/ijetms.2022.v06i05.131.

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The aim of the present study was to determination of antibacterial activities of ethanolic and aqueous leaf extracts of Madhunaashini (Gymnema sylvestre). Leaves of G. sylvestre was subjected to successive solvent extraction by continuous hot extraction (Soxhlet) with water and ethanol. The extracts were dissolved in dimethyl sulfoxide (DMSO) before testing the antibacterial activity. The antibacterial activity of leaf extracts G. sylvestre for Proteus mirabilis, E. coli and Pseudomonas aeruginosa was determined by agar well diffusion technique. Results delineated that zone of inhibition of G. Sylvestre for ethanolic & aqueous extracts for E. coli and P. mirabilis was found to be 17 mm & 13 mm and 19 mm & 16 mm respectively. Leaf extracts G. sylvestre for P. aeruginosa exhibited the zone of inhibition as 10 mm for ethanolic extract. In addition, ethanolic extract of G. Sylvestre exhibited antibacterial activity (19 mm) against P. mirabilis which is at par with that of standard antibiotic Streptomycin (20.5 mm). In conclusion, G. sylvestre could be used as an antibacterial agent since it was demonstrated from the current study findings that the ethanolic extract of G. sylvestre exhibited antibacterial activity at par with that of standard antibiotic streptomycin.

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&NA;. "Procalcitonin assay reduces antibacterial use in LRTIs." Inpharma Weekly &NA;, no. 1425 (February 2004): 4. http://dx.doi.org/10.2165/00128413-200414250-00008.

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KUSMIATI, KUSMIATI. "Antibacterial activity assay from Porphyridium cruentum microalgae." Biodiversitas, Journal of Biological Diversity 8, no. 1 (January 1, 2007): 48–53. http://dx.doi.org/10.13057/biodiv/d080110.

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Wanandy, Stephanus, Nynke Brouwer, Qian Liu, Andrew Mahon, Stephen Cork, Peter Karuso, Subramanyam Vemulpad, and Joanne Jamie. "Optimisation of the fluorescein diacetate antibacterial assay." Journal of Microbiological Methods 60, no. 1 (January 2005): 21–30. http://dx.doi.org/10.1016/j.mimet.2004.08.010.

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Khatri, Savita, Neetu Phougat, Mehak Dangi, and Anil Kumar Chhillar. "ANTIBACTERIAL, ANTIOXIDANT, CHEMICAL CONSTITUENTS, AND CYTOTOXICITY EVALUATION OF TERMINALIA ARJUNA (ROXB. EX DC.) WIGHT AND ARN." Asian Journal of Pharmaceutical and Clinical Research 10, no. 3 (March 1, 2017): 412. http://dx.doi.org/10.22159/ajpcr.2017.v10i3.16408.

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ABSTRACTObjective: The objective of this study is to evaluate the in vitro antibacterial and antioxidant prospective of Terminalia arjuna (leaves). The most activeextracts were examined for their chemical composition and cytotoxicity.Methods: The antibacterial activity of five different extracts were examined against 8 bacterial strains (5 Gram-positive and 3 Gram-negative) usingresazurin-based microtiter dilution assay (RMDA) and disk-diffusion assay. The antioxidant potential of five extracts was demonstrated using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay and superoxide radical scavenging assay. Chemical composition and cytotoxicity were assessed using gaschromatography-mass spectrometry (GC-MS) and hemolytic assay, respectively.Results: According to RMDA, the acetone extract (AE) exhibited highest antibacterial activity. The AE showed highest activity against Salmonellaenterica ser. typhi and Bacillus cereus with minimum inhibitory concentration, i.e., 195.31 μg/ml. In DPPH assay, AE showed the highest radicalscavenging activity with inhibition concentration50 23.09 μg/ml. In GC-MS analysis, the principal compound in AE was celidoniol (8.72 %). Accordingto the results of hemolytic assay, the AE showed non-toxic behavior upto 500 μg/ml.Conclusion: The present investigation represents T. arjuna as an incredible herb. The AE was found to possess promising antibacterial and antioxidantproperties.Keywords: Antibacterial, Antioxidant, Terminalia arjuna, Chemical composition, Cytotoxicity.

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Feridoz, Jannathul, and Anitha Roy. "ANTIBACTERIAL ACTIVITY OF AQUEOUS ALCOHOLIC EXTRACT OF ABUTILON INDICUM AERIAL PARTS AGAINST E .FAECALIS – AN INVITRO STUDY." Asian Journal of Pharmaceutical and Clinical Research 10, no. 5 (May 1, 2017): 80. http://dx.doi.org/10.22159/ajpcr.2017.v10i5.15636.

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Objective: To evaluate the antibacterial activity of the aqueous alcoholic extracts of Abutilon indicum aerial parts against Enterococcus faecalis.Methods: Agar well diffusion assay, as well as microbroth dilution assays, were used for determination of antibacterial activity. The assay was done intriplicate, and chlorhexidine 0.2% was used as the control.Results: Different concentrations (200, 400, and 800 mg/mL) of the ethyl acetate extract of A. indicum aerial parts showed dose-dependantantibacterial activity. The maximum zone of inhibition was 30 mm at the maximum concentration used (800 mg/mL), and the minimum inhibitoryconcentration/minimum bactericidal concentration was found to be 200 mg/mL.Conclusion: This study suggests that the aqueous alcoholic extract of A. indicum aerial parts contains promising antibacterial substances which arehaving activity against E. faecalis. E. faecalis being one of the major threats for root canal failure during endodontic treatment; plants with antibacterialactivity against E. faecalis will be promising.Keywords: Abutilon indicum, Enterococcus faecalis, Antibacterial activity, Root canal failure.

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KIM, MI-KYEONG, HYUN PARK, and TAE-JIN OH. "Antibacterial and Antioxidant Capacity of Polar Microorganisms Isolated from Arctic Lichen Ochrolechia sp." Polish Journal of Microbiology 63, no. 3 (2014): 317–22. http://dx.doi.org/10.33073/pjm-2014-042.

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Although many scientists have been studying lichens, the bacterial communities among lichens have not been fully explored. In this study, the biological activities of bacterial isolates from Arctic lichen Ochrolechia sp. were screened. Cell cultures were extracted using ethyl acetate, and these cultures were tested for antibacterial and antioxidant activities. To evaluate the antibacterial activities, we carried out a disk diffusion test and minimum inhibitory concentration assay. The inhibition zone diameter (mm) was 8 to 12, and its MIC value ranged from 222.0 to > 1000 μg/ml (control antibiotic ampicillin ranged from 0.31 to 0.58 μg/ml). PAMC26625 (Sphingomonas sp., sequence similarity: 99.108%) showed a high amount of total phenolic and total flavonoid contents within 5 extracts and also exhibited 77.23% and 80.02% in the 1,1-diphenyl-2-picryl-hydrazyl assay and the 2,2'-azino-bis(3-ethyl benzothiazoline-6-sulphonic acid) assay, respectively. In the ferric reducing antioxidant power assay, it was determined that PAMC26625 contained a higher amount of ferrous ion [8.72 mM Fe(II)/mg extract] than control ascorbic acid [6.21 mM Fe(II)/mg extract]. Our data indicated that they had potential to be novel sources of antibacterials and antioxidants.

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Moreno, Andréia De Haro, and Hérida Regina Nunes Salgado. "Microbiological Assay for Ceftazidime Injection." Journal of AOAC INTERNATIONAL 90, no. 5 (September 1, 2007): 1379–82. http://dx.doi.org/10.1093/jaoac/90.5.1379.

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Abstract A simple, sensitive, and specific biodiffusion assay for the antibacterial ceftazidime was developed using a strain of Staphylococcus epidermidis (ATCC 12228) as the test organism. Ceftazidime was measured in powder for injection at concentrations ranging from 100 to 400 g/mL. The calibration graph for ceftazidime was linear (r2 = 1), and the method validation showed that it was precise (relative standard deviation = 0.415) and accurate. The results obtained by biodiffusion assay were statistically calculated by linear parallel model and by means of regression analysis and were verified using analysis of variance. It was concluded that the microbiological assay is satisfactory for in vitro quantification of the antibacterial activity of ceftazidime in pharmaceuticals.

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Kang, Namyoung, Le Thi Thuy, Viet Dongquoc, and Joon Sig Choi. "Conjugation of Short Oligopeptides to a Second-Generation Polyamidoamine Dendrimer Shows Antibacterial Activity." Pharmaceutics 15, no. 3 (March 21, 2023): 1005. http://dx.doi.org/10.3390/pharmaceutics15031005.

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The growing evolution of bacterial resistance to antibiotics represents a global issue that not only impacts healthcare systems but also political and economic processes. This necessitates the development of novel antibacterial agents. Antimicrobial peptides have shown promise in this regard. Thus, in this study, a new functional polymer was synthesized by joining a short oligopeptide sequence (Phe-Lys-Phe-Leu, FKFL) to the surface of a second-generation polyamidoamine (G2 PAMAM) dendrimer as an antibacterial component. This method of synthesis proved simple and resulted in a high conjugation yield of the product FKFL-G2. To determine its antibacterial potential, FKFL-G2 was subsequently analyzed via mass spectrometry, a cytotoxicity assay, bacterial growth assay, colony-forming unit assay, membrane permeabilization assay, transmission electron microscopy, and biofilm formation assay. FKFL-G2 was found to exhibit low toxicity to noncancerous NIH3T3 cells. Additionally, FKFL-G2 had an antibacterial effect on Escherichia coli and Staphylococcus aureus strains by interacting with and disrupting the bacterial cell membrane. Based on these findings, FKFL-G2 shows promise as a potential antibacterial agent.

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Vasconcelos, Mayron Alves, Francisco Vassiliepe Sousa Arruda, Daniel Barroso de Alencar, Silvana Saker-Sampaio, Maria Rose Jane Ribeiro Albuquerque, Hélcio Silva dos Santos, Paulo Nogueira Bandeira, et al. "Antibacterial and Antioxidant Activities of Derriobtusone A Isolated fromLonchocarpus obtusus." BioMed Research International 2014 (2014): 1–9. http://dx.doi.org/10.1155/2014/248656.

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This study evaluated the effect of derriobtusone A, a flavonoid isolated fromLonchocarpus obtusus, on two important pathogenic bacteria,Staphylococcus aureusandEscherichia coli, as well as its antioxidant activity and toxicity. Planktonic growth assays were performed, and the inhibition of biofilm formation was evaluated. In addition, antioxidant activity was assessed by DPPH radical scavenging assay, ferrous ion chelating assay, ferric-reducing antioxidant power assay, andβ-carotene bleaching assay. Toxicity was evaluated by the brine shrimp lethality test. Results showed that derriobtusone A completely inhibited the planktonic growth ofS. aureusat 250 and 500 μg/mL; however, it did not have the same activity onE. coli. Derriobtusone A reduced the biomass and colony-forming unit (cfu) ofS. aureusbiofilm at concentrations of 250 and 500 μg/mL. In various concentrations, it reduced the biofilm biomass ofE. coli, and, in all concentrations, it weakly reduced the cfu. Derriobtusone A showed highly efficient antioxidant ability in scavenging DPPH radical and inhibitingβ-carotene oxidation. The compound showed no lethality toArtemiasp. nauplii. In conclusion, derriobtusone A may be an effective molecule againstS. aureusand its biofilm, as well as a potential antioxidant compound with no toxicity.

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Zulkamal, Liana Mohd, Nurul Afifah Ainna Zolhalim, Farizan Aris, Nurul Aili Zakaria, Farida Zuraina Mohd Yusof, Darah Ibrahim, and Mohd Taufiq Mat Jalil. "Bioactivity of Clitoria ternatea Crude Extracts Against Pathogenic Bacteria." Malaysian Applied Biology 52, no. 2 (June 30, 2023): 41–49. http://dx.doi.org/10.55230/mabjournal.v52i2.2542.

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Clitoria ternatea, sometimes referred to as the Asian pigeon wings blue pea, the butterfly pea, or the Darwin pea, is a Fabaceae plant species that has been shown to possess antibacterial effects against several pathogenic microbes. Hence, the present study has been carried out to access the antibacterial activity of C. ternatea flower extracted with water and methanol against pathogenic bacteria. The well and disk diffusion assays were performed to determine the antibacterial activity of C. ternatea flower extracts. The efficacy of the extracts was then evaluated via broth microdilution assay to obtain MIC and MBC values and the growth reduction assay. Meanwhile, the DPPH scavenging test was used to assess the antioxidant activity of the crude extracts. The results of the well and disc diffusion assays showed that Gram-positive bacteria were more sensitive to both extracts compared to Gram-negative bacteria. Meanwhile, the methanolic extract showed higher antibacterial activity on both Gram-positive and Gram-negative bacteria compared to the aqueous extract. The results of the MIC and MBC tests showed that the methanolic extract was bactericidal to both Gram-positive and Gram-negative bacteria. The aqueous extract, however, demonstrated bacteriostatic activity against Gram-negative bacteria and bactericidal activity solely against Gram-positive bacteria. After a 24-h exposure period, a growth reduction assay showed that the methanolic extract could suppress both Gram-positive and Gram-negative bacteria by up to 99%. Meanwhile, the aqueous extract showed an inhibition percentage value ranging from 75% to 96% after an incubation period. The aqueous extract had the lowest antioxidant activity, with an EC50 value of 87.78 µg/mL, whereas the methanolic extract had a fair amount of antioxidant activity when compared to the control (quercetin), according to the DPPH scavenging assay. The present study suggests that C. ternatea extracts as a potential antibacterial agent against pathogenic bacteria with significant antioxidant activity and this activity may be due to the presence of anthocyanin and its derivatives.

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Jamaludin, Nur Amira, Kamariah Bakar, and Jasnizat Saidin. "In Vitro Biological Activity of Three Marine Sponges From Theonella and Haliclona Genera Collected From Bidong Island, Terengganu, Malaysia." Malaysian Applied Biology 52, no. 2 (June 30, 2023): 51–59. http://dx.doi.org/10.55230/mabjournal.v52i2.2559.

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Marine sponges are primitive sessile animals that are rich sources of biologically active compounds. This paper aimed to assess the in-vitro biological activity of marine sponges from Theonella and Haliclona genera collected from Bidong Island, Terengganu, Malaysia. Biological activities such as antibacterial (discs diffusion assay), antioxidant (DPPH free-radical scavenging assay), and cytotoxicity activity (against cancerous HeLa, MCF-7, HepG-2 cell lines and the normal cell line Vero) were evaluated using MTT cytotoxicity assay. The bioassays were done on methanol extracts at different concentrations. Results indicate that T. swinhoei, and T. cf cupola showed low antibacterial capabilities ranging from 0 to 50 mg/mL and exhibited medium antioxidant activity with the IC50 value of 23.25 ± 1.57 and 18.52 ± 0.86 mg/mL, respectively. Cytotoxicity activities indicate that both species of T. swinhoei and T. cf cupola possesses toxic capabilities to inhibit the proliferation of all cancer cell lines used and demonstrated no significant toxicity for the normal cell line used in this study. Haliclona fascigera showed medium antibacterial activity against all Gram-positive bacteria and low activity against Gram-negative bacteria used. Haliclona fascigera exhibited antioxidant activity with an IC50 value of 1.80 ± 0.08 mg/mL and outcomes of the cytotoxicity activity assay against all cancer cells showed IC50 below 30 µg/mL. Marine sponges evaluated in this study indicate promising bioactive compounds that can be an excellent candidate for drug discovery in prospecting novel antibiotics and anticancer. Despite showing low antibacterial and medium antioxidant activity, species from both Theonella can be further studied in other assays to explore other biological activities whilst marine sponge H. fascigera possesses excellent capabilities in antibacterial, antioxidant, and cytotoxicity activities that can be further studied its chemical compositions for future research.

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Vaghela, Hiral, Rahul Shah, and Kokila A. Parmar. "Plant Mixture Mediated Biogenic Copper Nanoparticles: Antibacterial Assay." Current Nanomaterials 3, no. 2 (November 15, 2018): 86–94. http://dx.doi.org/10.2174/2405461503666180803152152.

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Ys, Hardi, Susan Semple, and Hans J. Griesser. "XPS Analysis and Antibacterial Assay of Novobiocin Coating." Procedia Chemistry 16 (2015): 592–99. http://dx.doi.org/10.1016/j.proche.2015.12.097.

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Kumarasamy, Yashodharan, Philip J. Cox, Marcel Jaspars, Lutfun Nahar, and Satyajit D. Sarker. "Bioactivity of Hirsutanolol, Oregonin and Genkwanin, Isolated from the Seeds of Alnus Glutinosa (Betulaceae)." Natural Product Communications 1, no. 8 (August 2006): 1934578X0600100. http://dx.doi.org/10.1177/1934578x0600100808.

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The antibacterial and free radical scavenging activity, and the general toxicity of two diarylheptanoids, hirsutanolol (1) and oregonin (2), and a flavonoid, genkwanin (3), isolated from the methanol extract of the seeds of Alnus glutinosa, were assessed by the 96 well-based serial dilution antibacterial assay using resazurin as an indicator of cell growth, the DPPH assay, and the brine shrimp lethality assay, respectively.

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Yuen, Hawk Leong, Szn Yi Chan, Yi En Ding, Suxing Lim, Gim Cheong Tan, and Chiew Ling Kho. "Development of a Novel Antibacterial Peptide, PAM-5, via Combination of Phage Display Selection and Computer-Assisted Modification." Biomolecules 13, no. 3 (March 2, 2023): 466. http://dx.doi.org/10.3390/biom13030466.

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Antibacterial peptides (ABPs) have been proposed as potential candidates for alternative antibacterial agents due to the extensive dissemination of antibiotic resistance. However, ABP isolation from natural resources can be tedious without consistent yield. Moreover, many natural ABPs are not developed for clinical application due to potential toxicity to mammalian cells. Therefore, the objective of this study was to develop a potent ABP with minimal toxicity via phage display selection followed by computer-assisted modification. Briefly, a 12-mer phage-displayed peptide library was used to isolate peptides that bound to the cell surface of Pseudomonas aeruginosa with high affinity. The affinity-selected peptide with the highest selection frequency was modified to PAM-5 (KWKWRPLKRKLVLRM) with enhanced antibacterial features by using an online peptide database. Using in vitro microbroth dilution assay, PAM-5 was shown to be active against a panel of Gram-negative bacteria and selected Gram-positive bacteria. Interestingly, the peptide was stable in human plasma by exhibiting a similar bactericidal effect via ex vivo assay. Scanning electron microscopy and SYTOX Green uptake assay revealed that PAM-5 was able to cause membrane disruption and permeabilization of the bacteria. Additionally, the peptide was also able to bind to bacterial DNA as demonstrated by gel retardation assay. In the time-kill assay, PAM-5 was shown to kill the bacteria rapidly in 10 min. More importantly, PAM-5 was non-cytotoxic to Vero cells and non-haemolytic to human erythrocytes at all concentrations tested for the antibacterial assays. Thus, this study showed that the combination of phage display screening and computer-assisted modification could be used to develop potent novel ABPs, and PAM-5 derived from these approaches is worth to be further elucidated for its potential clinical use.

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Tolentino, Jarel Elgin M., Arby Denise Nera, Mary Rose Roco, Nikko Beltran, and Else Dapat. "Qualitative phytochemical screening, antibacterial, antioxidant and cytotoxicity activities of the leaf extracts of Diospyros philippinensis A.DC. (Ebenaceae)." Research Journal of Chemistry and Environment 25, no. 10 (September 25, 2021): 84–89. http://dx.doi.org/10.25303/2510rjce8489.

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The use of medicinal plants for disease prevention and treatment is gaining recognition due to the various biologically active phytochemicals they produce. This study was conducted to assess the ability of the leaf extracts of Diospyros philippinensis A.DC., an endemic tree species in the Philippines for the presence of phytochemical constituents and was examined for potential bioactivities by employing several assays like Kirby-Bauer disc diffusion method, DPPH Assay and MTT assay for antibacterial, antioxidant and cytotoxicity activities of the extracts respectively. Phytochemical test results revealed the presence of alkaloids, flavonoids, saponins, phenols, quinones, cardiac glycosides, phlobatannins, carbohydrate, cardenolides and proteins. The leaf extracts were found to exhibit antibacterial activity against gram-positive bacteria and high antioxidant activity (99.22% ± 0.005) but no cytotoxicity effect was found against the selected cancer cell line. The study therefore concludes that D. philippinensis leaf extract can be a source of antibacterial and chemo preventive agents. This claim may be used as a basis for future investigation.

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Andriani, Yosie, Nurhamidah Nurhamidah, Lutfi Lutfi, and Suryati Suryati. "Antibacterial activity of secondary metabolites isolated from Ficus aurata (Miq.) fruits." Current Research in Biosciences and Biotechnology 3, no. 1 (August 31, 2021): 157–64. http://dx.doi.org/10.5614/crbb.2021.3.1/a2f9imf6.

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This research aimed to isolate chemical constituents from ethyl acetate and n-hexane fractions of Ficus aurata (Miq.) fruits and investigated their antibacterial activities. Chemical constituents were separated by using vacuum column chromatography, gravity column chromatography, and thin layer chromatography. The structures of the isolated compounds 3,4-dihydroxybenzoic acid (1) and β-sitosterol (2) were elucidated using various spectroscopic methods, including UV, IR, and NMR (1H-NMR, 13C-NMR, and DEPT). While, antibacterial activity was done by assay using Resazurin Microtiter Assay method. These 2 compounds reported as new constituents from F. aurata fruit. In addition, analysis of the bioassay showed that compound 1 had a notable antibacterial activity against gram negative (Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATTC 27853), and gram-positive bacteria (Staphylococcus aureusATCC 23235) with the Minimum Inhibitory Concentration (MIC) value of 0.1563 µg/mL, and it indicated the same MIC as cefadroxil (positive control). Compound 2 has weak antibacterial activity compared to cefadroxil (positive control). The results found that Ficus aurata (Miq.) fruits metabolites have antibacterial activity and show potency as antibacterial agent. Different kinds of bacteria and assay could be needed to investigate and support its antibacterial activity in the future.

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Hemmatian, Tahmineh, Kwon Ho Seo, Meltem Yanilmaz, and Juran Kim. "The Bacterial Control of Poly (Lactic Acid) Nanofibers Loaded with Plant-Derived Monoterpenoids via Emulsion Electrospinning." Polymers 13, no. 19 (October 3, 2021): 3405. http://dx.doi.org/10.3390/polym13193405.

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Plant-derived monoterpenoids have been shown to possess various biological effects, providing a scientific basis for their potential usage as antibacterial agents. Therefore, considering problems surrounding bacteria′s antibacterial resistance, the utilization of natural antimicrobial compounds such as monoterpenoids in different industries has gained much attention. The aim of this study was to fabricate and characterize various concentrations of plant-derived monoterpenoids, geraniol (G) and carvacrol (C), loaded into poly(lactic acid) (PLA) nanofibers via emulsion electrospinning. The antibacterial activities of the fabricated nanofibers were evaluated using three types of antibacterial assays (inhibition zone tests, live/dead bacterial cell assays, and antibacterial kinetic growth assays). Among the samples, 10 wt% carvacrol-loaded PLA nanofibers (C10) had the most bactericidal activity, with the widest inhibition zone of 5.26 cm and the highest visible dead bacteria using the inhibition zone test and live/dead bacterial cell assay. In order to quantitatively analyze the antibacterial activities of 5 wt% carvacrol-loaded PLA nanofibers (C5), C10, 5 wt% geraniol-loaded PLA nanofibers (G5), and 10 wt% geraniol-loaded PLA nanofibers (G10) against E. coli and S.epidermidis, growth kinetic curves were analyzed using OD600. For the results, we found that the antibacterial performance was as follows: C10 > C5 > G10 > G5. Overall, carvacrol or geraniol-loaded PLA nanofibers are promising antibacterial materials for improving fiber functionality.

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Dar, Umair Ikram, Farooq Saleem, and Saad Touqeer. "Antimicrobial and antioxidant activity of Embelia robusta: a common adulterant in black pepper." Pakistan Journal of Pharmaceutical Research 2, no. 2 (July 15, 2016): 136. http://dx.doi.org/10.22200/pjpr.20162136-141.

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The present study was aimed to investigate the phytochemistry as well as the antibacterial, antifungal, antioxidant and irritant activities of fruit of Embelia robusta. Agar-well diffusion method was used for antimicrobial study whereas for antioxidant activity three tests namely, DPPH assay, β-Carotene assay and ascorbic acid content were performed. The results from antibacterial assay showed presence of antibacterial activity in all the three plant extracts (methanol, chloroform and n-hexane). Significant antioxidant activity was also found to be present and plant extracts showed no irritant effect. Alkaloids, glycosides, phenolics, tannins and flavonoids were also detected in the plant. The study shows that the plant possesses significant medicinal value.

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Sarker, Satyajit, Lutfun Nahar, Srikanth Gujja, Shazi Begum, and Sezgin Celik. "Bioactivity of Centaurea persica boiss. (Asteraceae)." Archives of Biological Sciences 64, no. 2 (2012): 517–23. http://dx.doi.org/10.2298/abs1202517s.

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The free-radical-scavenging property, antibacterial activity and brine shrimp toxicity of petroleum ether (PE), dichloromethane (DCM) and methanol (MeOH) extracts of Centaurea persica, a Turkish medicinal plant, were assessed using the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) assay, the resazurin microtiter plate based assay, and the brine shrimp lethality assay, respectively. Additionally, the disc diffusion assay was also used to assess antibacterial activity. Only the MeOH extract of C. persica exhibited a significant free-radical-scavenging property in the DPPH assay, with an RC50 value of 0.025 mg/mL. However, in the TLC-based qualitative assay, petroleum ether and DCM extracts showed an extremely low level of free-radical-scavenging property. Among the solid-phase extraction fractions of the MeOH extract, the fractions eluted with 60% and 80% MeOH in water exhibited the highest level of free-radicalscavenging activity (RC50 = 0.010 and 0.015 mg/mL, respectively). While DCM extract showed reasonable antibacterial activity against five out of the nine test strains both in the disc diffusion assay and in the resazurin assay, the MeOH extract was highly active against both Escherichia coli and ampicillin-resistant E. coli strains. Among the solid-phase extraction fractions of the MeOH extract, fractions eluted with 80% MeOH in water and 100% MeOH displayed significant antibacterial potencies against both E. coli species. None of the extracts showed any significant toxicity towards brine shrimps (LD50 = >1.00 mg/mL).

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Zaman, Gaffar Sarwar, Mohammad Y. Alshahrani, Pranab Barua, Alanoud Aladel, Forhad Akhtar Zaman, Irfan Ahmad, Mohammad Idreesh Khan, Mejdi Snoussi, and Mohd Saeed. "Screening of the antioxidant and antibacterial effects of extracted essential oils from Thunbergia coccinea, Acacia polyacantha, Polygonum micrpcephallum, Abies spectabilis and Clerodendrum colebrookianum." Cellular and Molecular Biology 67, no. 4 (January 2, 2022): 56–67. http://dx.doi.org/10.14715/cmb/2021.67.4.7.

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During the previous few decades, it has been seen that there is a rapid emergence of pathogens resistant to multiple antibiotics. This has now become a global crisis. Some unexplored or less explored plants also provide some antibacterial, bactericidal and antioxidant properties. The antibacterial, bactericidal effects of extracted essential oils (EEOs) of Thunbergia coccinea, Acacia polyacantha, Polygonum micrpcephallum, Abies spectabilis and Clerodendrum colebrookianum was tested in comparison with standard antibiotics. The methods chosen were disc diffusion and deduction of minimum inhibitory concentration (MIC) by microbroth dilution assays of the EEOs against the bacterial strains.The antioxidant activity was found out utilizing DPPH free radical scavenging assay, MDA, Hydrogen peroxide radical inhibition assay and Superoxide radical inhibition assay (O 2 -). Some commonly used standard antibiotics (metronidazole, amoxicillin, clarithromycin, rifampicin, clindamycin and oxacillin,) were utilized to compare the EEO antibacterial action. Clerodendrum colebrookianum (85.17 ± 3.06 µg MDA/g extract) had a reasonable MDA. Acacia polyacantha in MIC had values of 3.86 ± 0.25 to 6.20 ± 0.16. Polygonum micrpcephallum had excessive H2O2 (48.27 ± 2.4 5%). The antibacterial actions determined by the paper disc‑diffusion technique of the EEO extracted from these plants showed that most had some antibacterial actions. Also, it was seen that the bactericidal action of the EEO extracted from E. alba was most potent against S. pyogenes (4.06 ± 0.15). The extract of the plant at varying concentrations (20, 40, 60, 80 and100 mg/mL) demonstrated noteworthy (P< 0.001) anthelmintic action in an effective change when the dose was adjusted. In conclusion, most of the tested plants contain a medicinal value, which can be utilized in the future to supplement artificial medicines and cure emerging diseases that create havoc for mankind.

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Houdkova, Marketa, Aishwarya Chaure, Ivo Doskocil, Jaroslav Havlik, and Ladislav Kokoska. "New Broth Macrodilution Volatilization Method for Antibacterial Susceptibility Testing of Volatile Agents and Evaluation of Their Toxicity Using Modified MTT Assay In Vitro." Molecules 26, no. 14 (July 9, 2021): 4179. http://dx.doi.org/10.3390/molecules26144179.

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In this study, a new broth macrodilution volatilization method for the simple and rapid determination of the antibacterial effect of volatile agents simultaneously in the liquid and vapor phase was designed with the aim to assess their therapeutic potential for the development of new inhalation preparations. The antibacterial activity of plant volatiles (β-thujaplicin, thymohydroquinone, thymoquinone) was evaluated against bacteria associated with respiratory infections (Haemophilus influenzae, Staphylococcus aureus, Streptococcus pneumoniae, Streptococcus pyogenes) and their cytotoxicity was determined using a modified thiazolyl blue tetrazolium bromide assay against normal lung fibroblasts. Thymohydroquinone and thymoquinone possessed the highest antibacterial activity against H. influenzae, with minimum inhibitory concentrations of 4 and 8 µg/mL in the liquid and vapor phases, respectively. Although all compounds exhibited cytotoxic effects on lung cells, therapeutic indices (TIs) suggested their potential use in the treatment of respiratory infections, which was especially evident for thymohydroquinone (TI > 34.13). The results demonstrate the applicability of the broth macrodilution volatilization assay, which combines the principles of broth microdilution volatilization and standard broth macrodilution methods. This assay enables rapid, simple, cost- and labor-effective screening of volatile compounds and overcomes the limitations of assays currently used for screening of antimicrobial activity in the vapor phase.

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Keekan, Kishor Kumar, and Sunil Rao Padmaraj. "Improved mass screening of medicinal plants for antibacterial activity by Leaf Disc antibacterial assay." Bangladesh Journal of Pharmacology 14, no. 4 (December 16, 2019): 198–201. http://dx.doi.org/10.3329/bjp.v14i4.42657.

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Ivanenkov, Yan A., Renat S. Yamidanov, Ilya A. Osterman, Petr V. Sergiev, Andrey A. Ayginin, Vladimir A. Aladinskiy, Anastasia V. Aladinskaya, et al. "Substituted Furanocoumarins as Novel Class of Antibacterial Translation Inhibitors." Combinatorial Chemistry & High Throughput Screening 22, no. 6 (September 5, 2019): 400–410. http://dx.doi.org/10.2174/1386207322666190723110539.

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Introduction: A variety of organic compounds has been reported to have antibacterial activity. However, antimicrobial resistance is one of the main problems of current anti-infective therapy, and the development of novel antibacterials is one of the main challenges of current drug discovery. Methods: Using our previously developed dual-reporter High-Throughput Screening (HTS) platform, we identified a series of furanocoumarins as having high antibacterial activity. The construction of the reporter system allows us to differentiate three mechanisms of action for the active compounds: inhibition of protein synthesis (induction of Katushka2S), DNA damaging (induction of RFP) or other (inhibition of bacterial growth without reporter induction). Results: Two primary hit-molecules of furanocoumarin series demonstrated relatively low MIC values comparable to that observed for Erythromycin (Ery) against E. coli and weakly induced both reporters. Dose-dependent translation inhibition was shown using in vitro luciferase assay, however it was not confirmed using C14-test. A series of close structure analogs of the identified hits was obtained and investigated using the same screening platform. Compound 19 was found to have slightly lower MIC value (15.18 µM) and higher induction of Katushka2S reporter in contrast to the parent structures. Moreover, translation blockage was clearly identified using both in vitro luciferase assay and C14 test. The standard cytotoxicity test revealed a relatively low cytotoxicity of the most active molecules. Conclusion: High antibacterial activity in combination with low cytotoxicity was demonstrated for a series of furanocoumarins. Further optimization of the described structures may result in novel and attractive lead compounds with promising antibacterial efficiency.

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Amran, Siti Sarah Diyana, Mohd Taufiq Mat Jalil, Aziyah Abdul Aziz, and Mohd Fakharul Zaman Raja Yahya. "Methanolic Extract Of Swietenia macrophylla Exhibits Antibacterial And Antibiofilm Efficacy Against Gram-Positive Pathogens." Malaysian Applied Biology 52, no. 2 (June 30, 2023): 129–38. http://dx.doi.org/10.55230/mabjournal.v52i2.2642.

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Gram-positive pathogens cause infections such as pneumonia, skin infections, anthrax, and sinusitis. The objective of this study was to determine the phytochemical profile, antibacterial and antibiofilm efficacy of Swietenia macrophylla methanolic extract (SMME) against Gram-positive pathogens. The secondary metabolites of SMME were analyzed using GC-MS while the antibacterial efficacy of SMME against Staphylococcus aureus ATCC 33862, Bacillus cereus ATCC 11778, Streptococcus pneumonia ATCC 19615, and Clostridium sporogenes ATCC 13124 was assessed using MIC and MBC assays. Biofilm biomass assay and time-kill assay were performed to determine the antibiofilm activity of SMME against the pathogens. Results demonstrated that six common antibacterial secondary metabolites were present in the SMME. The major compound was found to be β-amyrin (22.8%). The SMME showed the lowest MIC values against B. cereus (31.25 µg/mL) and C. sporogenes (31.25 µg/mL) and the lowest MBC value against S. aureus (1000 µg/mL). The SMME also significantly (p<0.05) inhibited all the biofilms. It started to inhibit S. pneumonia and C. sporogenes biofilms after 12 h of exposure. On the other hand, the BIC50 value showed that the SMME was most effective against B. cereus. In conclusion, the secondary metabolites in the SMME may contribute to the antibacterial and antibiofilm efficacy against Gram-positive pathogens.

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Laubscher, Wikus Ernst, and Marina Rautenbach. "Direct Detection of Antibacterial-Producing Soil Isolates Utilizing a Novel High-Throughput Screening Assay." Microorganisms 10, no. 11 (November 11, 2022): 2235. http://dx.doi.org/10.3390/microorganisms10112235.

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The ever-increasing global threat of common infections developing resistance to current therapeutics is rapidly accelerating the onset of a primitive post-antibiotic era in medicine. The prevention of further antimicrobial resistance development is unlikely due to the continued misuse of antibiotics, augmented by the lack of discovery of novel antibiotics. Screening large libraries of synthetic compounds have yet to offer effective replacements for current antibiotics. Due to historical successes, discovery from large and diverse natural sources and, more specifically, environmental bacteria, may still yield novel alternative antibiotics. However, the process of antibiotic discovery from natural sources is laborious and time-consuming as a result of outdated methodologies. Therefore, we have developed a simple and rapid preliminary screening assay to identify antibacterial-producing bacteria from natural sources. In brief, the assay utilizes the presence or absence of luminescence in bioluminescent reporter bacteria and test bacterium co-cultures in a 96-well plate format to determine the absence or presence of antibacterial compound production. Our assay, called the bioluminescent simultaneous antagonism (BSLA) assay, can accurately distinguish between known antibacterial-producing and non-producing test bacteria. The BSLA assay was validated by screening 264 unknown soil isolates which resulted in the identification of 10 antibacterial-producing isolates, effectively decreasing the pool of isolates for downstream analysis by 96%. By design, the assay is simple and requires only general laboratory equipment; however, we have shown that the assay can be scaled to automated high-throughput screening systems. Taken together, the BSLA assay allows for the rapid pre-screening of unknown bacterial isolates which, when coupled with innovative downstream dereplication and identification technologies, can effectively fast-track antimicrobial discovery.

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Prastiyanto, Muhammad Evy, Fandhi Adi Wardoyo, Wildiani Wilson, and Sri Darmawati. "Antibacterial Activity of Various Extracts of Averrhoa bilimbi against Multidrug Resistant Bacteria." Biosaintifika: Journal of Biology & Biology Education 12, no. 2 (August 1, 2020): 163–68. http://dx.doi.org/10.15294/biosaintifika.v12i2.23600.

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The multi-drug resistance (MDR) bacteria is a global health problem that causes high mortality every year. Therefore, novel antibacterial agents are needed from natural biological sources. This research aimed to investigate the antibacterial activities of various crude extracts of Averrhoa bilimbi against MDR bacteria. The antibacterial activity was calculated based on the use agar well diffusion assay and the minimum bactericidal concentration (MBC) using Mueller–Hinton broth in a microdilution method. Bacteria from wells were subcultured using inoculating loop onto a 5% sheep BAP. The best antibacterial activity, calculated as the most widely inhibitory zone and the smallest MBC values. The ethanolic extract showed antibacterial activity against the all MDR bacterial test in the agar well diffusion assay (10-14.5 mm inhibition diameter). The MBC of water extract against ESβL + CR Pseudomonas aeruginosa showed the best antibacterial activity (12.5 mg/mL). The fruit of bilimbi was shown to be potentially developed as antibacterial agents, especially for MDR strains. Further in vivo research and discovery of action mode are needed to shed light on their antibacterial effects. This study can provide new information about the benefits of bilimbi as a source of natural antibacterial againts MDR-bacteria

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Rattanasuk, Surachai, Rujirek Boongapim, and Tannatorn Phiwthong. "Antibacterial activity of Cathormion umbellatum." Bangladesh Journal of Pharmacology 16, no. 3 (July 13, 2021): 91–95. http://dx.doi.org/10.3329/bjp.v16i3.53420.

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The aim of this study was to determine the antibacterial activity of Cathormion umbellatum extracts against seven antibiotic-resistant bacteria. The pods, leaves and branches of C. umbellatum were extracted with ethanol and methanol. The disc diffusion assay was used to screen the antibacterial activity and broth microdilution and colorimetric assay were used to measure the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) values. The result indicated that the highest inhibition zone (11 mm) was presented in ethanolic pods extract against multidrug resistance Klebsiella pneumoniae. The lowest MIC value of 0.05 mg/mL was obtained from branch extracted with ethanol against colistin resistant Pseudomonas aeruginosa. The lowest MBC values of 1.56 mg/mL were obtained when using C. umbellatum leaves extracted with methanol against all test antibiotic-resistant bacteria. This is the first report presented C. umbellatum extracts have the potential to eliminate antibiotic-resistant bacteria in patients. These findings show the antibacterial effect of C. umbellatum.

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Ravi, Lokesh, Manasvi V, and Praveena Lakshmi B. "ANTIBACTERIAL AND ANTIOXIDANT ACTIVITY OF SAPONIN FROM ABUTILON INDICUM LEAVES." Asian Journal of Pharmaceutical and Clinical Research 9, no. 9 (December 1, 2016): 344. http://dx.doi.org/10.22159/ajpcr.2016.v9s3.15064.

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ABSTRACTObjective: Aim of this study is to analyze the antibacterial and antioxidant potential of crude saponin extract (CSE) from Abutilon indicum leaves.Methods: CSE was subjected for gas chromatography-mass spectrometry (GC-MS) analysis to identify its components. Antibacterial potentialwas analyzed using agar well diffusion method and minimum inhibitory concentration (MIC) was detected using 96-well plate method, againstStaphylococcus aureus (MTCC: 3160) and Escherichia coli (MTCC: 443). DNA damage study was performed using comet assay. Antioxidant capabilitywas studied using 2,2-diphenyl-1-picrylhydrazyl scavenging assay.Results: GC-MS analysis suggested a library match to benzene-1-4-bis(phenylmethyl), with a molecular weight of 258 g/mol to be the majorcomponent in the CSE at 21.25 RT. CSE demonstrated 96.16% free radical scavenging activity at 2.5 mg/ml concentration. CSE demonstrateda significant antibacterial activity in the well diffusion assay, S. aureus 17 mm and E. coli 15 mm, with a MIC value of 1.11 mg/ml. Comet assaydemonstrated no DNA damage.Conclusion: These results conclude that CSE of A. indicum leaves possesses promising antibacterial and antioxidant potential.Keywords: Abutilon indicum, Saponin, Escherichia coli, Staphylococcus aureus, 2,2-diphenyl-1-picrylhydrazyl, Antibacterial assay.

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Fuentes, Rolly Garnace, Gio Martin A. Ocfemia, and Galileo Gregory Abrasaldo. "Antibacterial and Zebrafish-based Screening for Wnt Signal Inhibitory Activities of Syzygium polycephaloides (C.B. Robb. Merr.) Bark Extracts." ASM Science Journal 15 (May 17, 2021): 1–6. http://dx.doi.org/10.32802/asmscj.2021.438.

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Syzygium polycephaloides, a plant native to Southeast Asia, is used to cure common illnesses. In this study, the methanolic bark extracts of S. polycephaloides was evaluated for their antibacterial activity and screened for their Wnt signal inhibitory activity using zebrafish-based assay. In the antibacterial assay, the extracts were tested against Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeroginosa, and Escherichia coli using disk diffusion assay. On the other hand, zebrafish-based screening was used to determine the inhibitory potential of S. polycephaloides against the Wnt signal. Zebrafish embryos were treated with LiCl to upregulate the Wnt signal which produces eyeless phenotype. The methanolic extracts had antibacterial activity against the test microorganisms except P. aeruginosa. After fractionation, ethyl acetate (EtOAc) and aqueous fractions exhibited wide-spectrum antibacterial activity. For the Wnt signal inhibitory activity screening, the LiCl-treated embryos were rescued to their normal eye development after treatment with the S. polycephaloides bark extracts (100 g/mL). The results suggest that the extracts may have inhibited the Wnt signal. This study shows that the S. polycephaloides is a potent source of antibacterial compounds and Wnt inhibitors.

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Young, Katherine, Hiranthi Jayasuriya, John G. Ondeyka, Kithsiri Herath, Chaowei Zhang, Srinivas Kodali, Andrew Galgoci, et al. "Discovery of FabH/FabF Inhibitors from Natural Products." Antimicrobial Agents and Chemotherapy 50, no. 2 (February 2006): 519–26. http://dx.doi.org/10.1128/aac.50.2.519-526.2006.

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ABSTRACT Condensing enzymes are essential in type II fatty acid synthesis and are promising targets for antibacterial drug discovery. Recently, a new approach using a xylose-inducible plasmid to express antisense RNA in Staphylococcus aureus has been described; however, the actual mechanism was not delineated. In this paper, the mechanism of decreased target protein production by expression of antisense RNA was investigated using Northern blotting. This revealed that the antisense RNA acts posttranscriptionally by targeting mRNA, leading to 5′ mRNA degradation. Using this technology, a two-plate assay was developed in order to identify FabF/FabH target-specific cell-permeable inhibitors by screening of natural product extracts. Over 250,000 natural product fermentation broths were screened and then confirmed in biochemical assays, yielding a hit rate of 0.1%. All known natural product FabH and FabF inhibitors, including cerulenin, thiolactomycin, thiotetromycin, and Tü3010, were discovered using this whole-cell mechanism-based screening approach. Phomallenic acids, which are new inhibitors of FabF, were also discovered. These new inhibitors exhibited target selectivity in the gel elongation assay and in the whole-cell-based two-plate assay. Phomallenic acid C showed good antibacterial activity, about 20-fold better than that of thiolactomycin and cerulenin, against S. aureus. It exhibited a spectrum of antibacterial activity against clinically important pathogens including methicillin-resistant Staphylococcus aureus, Bacillus subtilis, and Haemophilus influenzae.

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Wirasisya, Dyke Gita, Yohanes Juliantoni, and Wahida Hajrin. "Pengaruh Dua Metode Pengeringan Pada Aktivitas Antibakteri Ashitaba (Angelica keiskei ) Terhadap Streptococcus mutans." Jurnal Farmasi Galenika (Galenika Journal of Pharmacy) (e-Journal) 4, no. 1 (April 11, 2018): 18–25. http://dx.doi.org/10.22487/j24428744.2018.v4.i1.9629.

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The aim of this study was to determine a change that occurs in total phenolic content (TPC) and antibacterial activity of ashitaba (Angelica keiskei) after dried using two different methods : sun and oven drying. The effectiveness of the drying methods was evaluated in term of total phenolic content (TPC) by using spectrophotometric assay with Folin-Ciocalteu reagent and antibacterial activity againts Streptococcus mutans by in vitro macrodilution assay. Oven drying at 60oC possessed high TPC (2,98 ± 0,0935 g EAG/100g) compared to sun drying method (1,72 ± 0,0142 g EAG/100g). Simillar pattern was also observed in antibacterial activity. Oven drying have higher antibacterial activity with the MBC (minimal bactericidal concentration) value of 0,5 mg/mL againts Streptococcus mutans. Therefore, sun drying is not suggested for drying method of ashitaba in terms of total phenolic content and antibacterial activity compared with oven drying methods.

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Septama, Abdi Wira, and Pharkphoom Panichayupakaranant. "Antibacterial assay-guided isolation of active compounds fromArtocarpus heterophyllusheartwoods." Pharmaceutical Biology 53, no. 11 (May 5, 2015): 1608–13. http://dx.doi.org/10.3109/13880209.2014.996819.

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Falk, Shaun P., Andrew T. Ulijasz, and Bernard Weisblum. "Differential Assay for High-Throughput Screening of Antibacterial Compounds." Journal of Biomolecular Screening 12, no. 8 (December 2007): 1102–8. http://dx.doi.org/10.1177/1087057107308161.

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The previously described Bacillus subtilis reporter strain BAU-102 is capable of detecting cell wall synthesis inhibitors that act at all stages of the cell wall synthesis pathway. In addition, this strain is capable of detecting compounds with hydrophobic/ surfactant activity and alternative mechanisms of cell wall disruption. BAU-102 sequesters preformed β-gal in the periplasm, suggesting leakage of β-gal as the means by which this assay detects compound activities. A model is proposed according to which β-gal release by BAU-102 reflects activation of pathways leading to autolysis. The authors also report a simplified high-throughput assay using BAU-102 combined with the fluorogenic substrate N-methylumbelliferyl-β-D-galactoside as a single reagent. Cell wall inhibitors release β-gal consistently only after 60 min of incubation, whereas compounds with surfactant activity show an almost immediate release. A high-throughput screen of a 480-compound library of known bioactives yielded 8 compounds that cause β-gal release. These results validate the BAU-102 assay as an effective tool in antimicrobial drug discovery. ( Journal of Biomolecular Screening 2007:1102-1108)

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Ivanenkov, Yan A., Renat S. Yamidanov, Ilya A. Osterman, Petr V. Sergiev, Vladimir A. Aladinskiy, Anastasia V. Aladinskaya, Victor A. Terentiev, et al. "Large-scale High-throughput Screening Revealed 5'-(carbonylamino)-2,3'- bithiophene-4'-carboxylate as Novel Template for Antibacterial Agents." Current Drug Discovery Technologies 17, no. 5 (December 23, 2020): 716–24. http://dx.doi.org/10.2174/1570163816666190603095521.

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Background: The key issue in the development of novel antimicrobials is a rapid expansion of new bacterial strains resistant to current antibiotics. Indeed, World Health Organization has reported that bacteria commonly causing infections in hospitals and in the community, e.g. E. Coli, K. pneumoniae and S. aureus, have high resistance vs the last generations of cephalosporins, carbapenems and fluoroquinolones. During the past decades, only few successful efforts to develop and launch new antibacterial medications have been performed. This study aims to identify new class of antibacterial agents using novel high-throughput screening technique. Methods: We have designed library containing 125K compounds not similar in structure (Tanimoto coeff.< 0.7) to that published previously as antibiotics. The HTS platform based on double reporter system pDualrep2 was used to distinguish between molecules able to block translational machinery or induce SOS-response in a model E. coli system. MICs for most active chemicals in LB and M9 medium were determined using broth microdilution assay. Results: In an attempt to discover novel classes of antibacterials, we performed HTS of a large-scale small molecule library using our unique screening platform. This approach permitted us to quickly and robustly evaluate a lot of compounds as well as to determine the mechanism of action in the case of compounds being either translational machinery inhibitors or DNA-damaging agents/replication blockers. HTS has resulted in several new structural classes of molecules exhibiting an attractive antibacterial activity. Herein, we report as promising antibacterials. Two most active compounds from this series showed MIC value of 1.2 (5) and 1.8 μg/mL (6) and good selectivity index. Compound 6 caused RFP induction and low SOS response. In vitro luciferase assay has revealed that it is able to slightly inhibit protein biosynthesis. Compound 5 was tested on several archival strains and exhibited slight activity against gram-negative bacteria and outstanding activity against S. aureus. The key structural requirements for antibacterial potency were also explored. We found, that the unsubstituted carboxylic group is crucial for antibacterial activity as well as the presence of bulky hydrophobic substituents at phenyl fragment. Conclusion: The obtained results provide a solid background for further characterization of the 5'- (carbonylamino)-2,3'-bithiophene-4'-carboxylate derivatives discussed herein as new class of antibacterials and their optimization campaign.

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Moussa, Shaaban H., Ahmed A. Tayel, Ahmed A. Al-Hassan, and A. Farouk. "Tetrazolium/Formazan Test as an Efficient Method to Determine Fungal Chitosan Antimicrobial Activity." Journal of Mycology 2013 (June 3, 2013): 1–7. http://dx.doi.org/10.1155/2013/753692.

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Fungal chitosan was extracted from Aspergillus niger mycelia. The produced chitosan was characterized with deacetylation degree of 89.2%, a molecular weight of 2.4 × 104 Da, and 96.0% solubility in 1% acetic acid solution. The antibacterial activity of fungal chitosan was evaluated against two foodborne pathogens, that is, Salmonella typhimurium and Staphylococcus aureus, using the established antibacterial assays, for example, zone of growth inhibition and agar plat count tests, and using 2,3,5,-triphenyltetrazolium chloride (TTC) as chromogenic marker for qualitative and quantitative determining of antibacterial potentiality. The TTC (0.5% w/v) was added, at concentration of 10%, to cultured broth, containing chitosan with different concentrations then the formed formazan was separated. The formation of red formazan could be considered as a qualitative indication for antibacterial activity, whereas the measurement of color intensity for the resuspended red formazan, using spectrophotometer at 480 nm, provided a quantitative evidence for the strength of the used antibacterial agent. Regarding the rapidity, technical simplicity, and cost-effectiveness, TTC assay could be recommended as an efficient alternative method for qualitative and quantitative determination of chitosan antibacterial activity and could be suggested for general evaluation of antibacterial agents.

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Balázs, Viktória Lilla, Lilla Nagy-Radványi, Rita Filep, Erika Kerekes, Béla Kocsis, Marianna Kocsis, and Ágnes Farkas. "In Vitro Antibacterial and Antibiofilm Activity of Hungarian Honeys against Respiratory Tract Bacteria." Foods 10, no. 7 (July 14, 2021): 1632. http://dx.doi.org/10.3390/foods10071632.

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Honey is a rich source of carbohydrates, while minor compounds such as amino acids and polyphenols contribute to its health-promoting effects. Honey is one of the oldest traditional remedies applied for microbial infections, due to its antibacterial, anti-inflammatory, and antioxidant properties. The aim of this study was to investigate the antibacterial and antibiofilm effects of Hungarian black locust, linden, and sunflower honeys against the most common biofilm-forming respiratory tract pathogens Haemophilus spp., Pseudomonas aeruginosa, and Streptococcus pneumoniae. The unifloral character of all three honey types was confirmed by melissopalynological analysis. The antibacterial activity of each honey sample against each bacterium strain was proven with agar well diffusion assay and thin layer chromatography—direct bioautography. Kinetics and mechanisms of antibacterial action were clarified with time-kill assay and membrane degradation study. The anti-biofilm activity was evidenced using crystal violet assay. In each assay, linden honey was the most effective, followed by sunflower and black locust honey. In addition, each honey sample had greater potential to suppress respiratory tract bacteria, compared to major sugar components. In conclusion, honey in general and linden honey in particular, can have a role in the treatment of respiratory tract infections caused by biofilm-forming bacteria.

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48

Limban, Carmen, Diana Camelia Nuta, Alexandru Vasile Missir, Roxana Roman, Miron Teodor Caproiu, Florea Dumitrascu, Lucia Pintilie, et al. "Synthesis and Characterization of New Fluoro/Trifluoromethyl-Substituted Acylthiourea Derivatives with Promising Activity against Planktonic and Biofilm-Embedded Microbial Cells." Processes 8, no. 5 (April 26, 2020): 503. http://dx.doi.org/10.3390/pr8050503.

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The aim of this study was preparation of new derivatives based on 2-((4-chlorophenoxy)methyl)-N-(arylcarbamothioyl)benzamide structure; the new compounds were characterized by IR, NMR (1H, 13C) spectroscopy, and elemental analysis. The obtained compounds were evaluated for their in vitro antimicrobial activity against planktonic and biofilm-embedded microbial cells (Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa, Candida albicans), by qualitative and quantitative assays. Some of the compounds revealed promising antibacterial and antifungal activities, with low minimum inhibitory concentration values between 0.15 and 2.5 mg/mL and minimal biofilm eradication concentrations of 0.019–2.5 mg/mL. To investigate the potential target of their antibacterial activity, in silico drug-likeness and molecular docking screenings on Staphylococcus aureus DNA gyrase were performed. The compound with the best antibacterial activity (1g) was docked into topoisomerase II DNA gyrase enzymes (PDB ID: 2XCS) and showed valuable interactions with the target protein along with good docking scores, suggesting that it can act by the inhibition of DNA replication. The tested compounds exhibited only a poor antioxidant activity, as revealed by the in vitro assay using 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay.

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Ambrosio, Carmen M. S., Severino M. de Alencar, Andrea M. Moreno, and Eduardo M. Da Gloria. "Evaluation of the selective antibacterial activity of Eucalyptus globulus and Pimenta pseudocaryophyllus essential oils individually and in combination on Enterococcus faecalis and Lactobacillus rhamnosus." Canadian Journal of Microbiology 64, no. 11 (November 2018): 844–55. http://dx.doi.org/10.1139/cjm-2018-0021.

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Essential oils (EOs), as substitutes for antibiotics in animal diets, should have selective antibacterial activity between pathogenic and beneficial bacteria from the animal gut. Thus, this study evaluated the selective antibacterial activity of Eucalyptus globulus (EG) and Pimenta pseudocaryophyllus (PP) EOs on Enterococcus faecalis as a surrogate model of pathogenic bacterium and on Lactobacillus rhamnosus as a beneficial bacterium model. The EOs antibacterial activity was evaluated by determination of minimal inhibitory concentrations (MICs), minimal bactericidal concentration (MBCs), and fractional inhibitory concentration (FIC) indices. The time-kill and sequential exposure assays were also performed, but using only the EG oil, which was the best selective EO, since it had a MIC lower on E. faecalis (7.4 mg/mL) than on L. rhamnosus (14.8 mg/mL). FIC index values showed that the combination of the two EOs had an indifferent effect (1.25 and 2.03) on E. faecalis and an additive effect (1.00) on L. rhamnosus. The time-kill assay showed that EG oil was able to kill E. faecalis within 15 min of treatment (∼5 log reduction) and caused a reduction ∼3 log of L. rhamnosus viability. The sequential exposure assay showed that EG oil (at MIC/2) produced higher reduction on E. faecalis viability (∼3 log) than on L. rhamnosus (∼2 log) as well. Therefore, L. rhamnosus presented higher tolerance to the antibacterial activity of EG oil than E. faecalis did.

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Yang, Jun, Wei-Dan Zhang, Jia-Mei Song, Hui-Tao Wang, and Saeed Rohani. "Drug-Eluting Nanofibrous Polymeric Tubes for Urethra Reconstruction and Prevention of Its Infection: An In Vitro Study." Journal of Biomedical Nanotechnology 18, no. 11 (November 1, 2022): 2651–60. http://dx.doi.org/10.1166/jbn.2022.3465.

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In the current study, nanofibrous polymeric tubes were fabricated to develop a drug-delivering artificial urethra. Scaffolds were produced via electrospinning of collagen and polycaprolacton solution loaded with trimethoprim and curcumin and then rolled up to produce urethra-resembling tubes. Various In Vitro experiments such as scanning electron microscopy imaging, cell attachment studies, cytocompatiblity test, cell protection assay, antibacterial tests, biodegradation analysis, antiinflammatory assay, and gene expression analysis were utilized for the characterization of the scaffolds. In Vitro experiments showed that the electrospun tubes were biocompatible with human urothelial cells and promoted their adhesion and proliferation. Antibacterial assay showed that drug-delivering scaffolds showed a strong antibacterial activity against Escherichia coli Staphylococcus aureus bacteria. Meantime, the developed scaffolds downregulated fibrosis-associated genes. This study suggests potential applicability of polycaprolacton/collagen/curcumin/ trimethoprim tubes for urethra reconstruction surgeries and prevention of its bacterial infection.

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Journal articles on the topic 'Antibacterial Assay'

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