Journal articles: 'Chemistry of bitter substances'

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Hoffmann, Krystyna, Józef Hoffmann, Marta Huculak-Mączka, and Jakub Skut. "Investigation of applying calcium oxide for the removal of bitter substances from hop wastes." Polish Journal of Chemical Technology 13, no. 1 (January 1, 2011): 35–40. http://dx.doi.org/10.2478/v10026-011-0007-8.

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Investigation of applying calcium oxide for the removal of bitter substances from hop wastes Utilization of brewery wastes is one of the solutions for the production of the fodder supplements containing biogenic nutrients. The condition of such application is to meet the requirements included in the regulations regarding animal feeding, particularly removing a bitter taste. The aim of the performed investigations was the removal of bitter acids from the post-extraction hop waste using the calcium oxide addition. For the examination hop wastes obtained as a by-product from the CO2 plant extraction in supercritical conditions, were applied. Physicochemical properties of the waste samples collected for the investigations were determined by applying the available standard analytical techniques. The analyses of the determination of bitter acids were carried out by the high performance liquid chromatography method. During the experiments very good effects of bitter acids removal from hop wastes, were obtained by using CaO suspensions in water. The investigations on the influence of the CaO concentration in suspension on the efficiency of bitter acids removal indicate the possibility of applying suspensions by 2 wt% for this purpose.

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Yoshimatsu, Jumpei, Kiyoshi Toko, Yusuke Tahara, Misaki Ishida, Masaaki Habara, Hidekazu Ikezaki, Honami Kojima, Saeri Ikegami, Miyako Yoshida, and Takahiro Uchida. "Development of Taste Sensor to Detect Non-Charged Bitter Substances." Sensors 20, no. 12 (June 18, 2020): 3455. http://dx.doi.org/10.3390/s20123455.

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A taste sensor with lipid/polymer membranes is one of the devices that can evaluate taste objectively. However, the conventional taste sensor cannot measure non-charged bitter substances, such as caffeine contained in coffee, because the taste sensor uses the potentiometric measurement based mainly on change in surface electric charge density of the membrane. In this study, we aimed at the detection of typical non-charged bitter substances such as caffeine, theophylline and theobromine included in beverages and pharmaceutical products. The developed sensor is designed to detect the change in the membrane potential by using a kind of allosteric mechanism of breaking an intramolecular hydrogen bond between the carboxy group and hydroxy group of aromatic carboxylic acid (i.e., hydroxy-, dihydroxy-, and trihydroxybenzoic acids) when non-charged bitter substances are bound to the hydroxy group. As a result of surface modification by immersing the sensor electrode in a modification solution in which 2,6-dihydroxybenzoic acid was dissolved, it was confirmed that the sensor response increased with the concentration of caffeine as well as allied substances. The threshold and increase tendency were consistent with those of human senses. The detection mechanism is discussed by taking into account intramolecular and intermolecular hydrogen bonds, which cause allostery. These findings suggest that it is possible to evaluate bitterness caused by non-charged bitter substances objectively by using the taste sensor with allosteric mechanism.

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Rhyu, Mee-Ra, Yiseul Kim, and Takumi Misaka. "Suppression of hTAS2R16 Signaling by Umami Substances." International Journal of Molecular Sciences 21, no. 19 (September 24, 2020): 7045. http://dx.doi.org/10.3390/ijms21197045.

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Interaction between umami and bitter taste has long been observed in human sensory studies and in neural responses in animal models, however, the molecular mechanism for their action has not been delineated. Humans detect diverse bitter compounds using 25-30 members of the type 2 taste receptor (TAS2R) family of G protein-coupled receptor. In this study, we investigated the putative mechanism of antagonism by umami substances using HEK293T cells expressing hTAS2R16 and two known probenecid-insensitive mutant receptors, hTAS2R16 N96T and P44T. In wild type receptor, Glu-Glu, inosine monophosphate (IMP), and l-theanine behave as partial insurmountable antagonists, and monosodium glutamate (MSG) acts as a surmountable antagonist in comparison with probenecid as a full insurmountable antagonist. The synergism with IMP of umami substances still stands in the suppression of hTAS2R16 signaling. In mutagenesis analysis, we found that Glu-Glu, MSG, and l-theanine share at least one critical binding site on N96 and P44 with probenecid. These results provide the first evidence for a direct binding of umami substances to the hTAS2R16 through the probenecid binding pocket on the receptor, resulting in the suppression of bitterness.

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Sincar, Cerasela Dorina, Camelia Ana Grigore, Silvia Martu, Liliana Lacramioara Pavel, Alina Calin, Alina Plesea Condratovici, and Bianca Ioana Chesaru. "Chemical Senses Taste Sensation and Chemical Composition." Materiale Plastice 54, no. 1 (March 30, 2017): 172–74. http://dx.doi.org/10.37358/mp.17.1.4810.

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Taste and smell are chemical senses, which means that the receptors (chemoreceptors) of these senses respond to chemical stimuli. In order for a substance to produce a taste sensation, it should be ingested in a solution or subsequently dissolved in saliva; a solid substance put in the mouth perfectly dry is tasteless. Therefore, taste receptors or taste buds occur only on wet surfaces, more precisely in the oral cavity in land vertebrates; however, in aquatic animals, these receptors are scattered all over the body. There are functionally different types of receptors for each of the primary tastes and the distribution of each type is not even on the surface of the tongue mucosa. The sweet and sour sensitive buds are located mainly on the tip of the tongue, those sensitive to acids are located on the sides of the tongue and those stimulated by the bitter taste are located towards the back of the tongue and in the epiglottis area. Taste may be generated by substances which touch the taste buds through the blood; thus, histamine injected intravenously causes a metallic taste, glucin a sweet taste, whereas jaundice may trigger a bitter taste due to the big concentration of gallbladder constituents in the blood.

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Khamidov, Arifjon Zhakhongirovich, Hakim Rakhmanovich Tukhtaev, Sabirjan Nigmatovich Aminov, and Bakhtigul Zhavli Kizi Azimova. "PROCESSING OF BITTER ALMOND KERNELS AND OBTAINING EXTRACTS BASED ON THEM." chemistry of plant raw material, no. 2 (June 10, 2021): 301–7. http://dx.doi.org/10.14258/jcprm.2021027775.

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Mountain almond kernels (seed) processing products are of practical interest as fungicidal, antimicrobial and antiviral substances, and also find application in medicine and cosmetics for various purposes. The composition and some technological properties of seeds of mountain almond seed (Amygdalus communis L. varietas amara DC.). Cultivated in the mountain zones (Bostanlyq) of Uzbekistan were studied. To obtain seeds from cold pressing, fatty oil was separated. The cake was degreased with organic solvents, the residues were dried and ground. Using gas-liquid chromatography, the presence of 3.24% amygdalin in the composition of crushed powder of bitter almonds was established. Spectral analysis of bitter almond powder showed the presence of Mg, P, Ca, K, Si, Sr, Fe, Mn, B, Cu and other elements. The nitrogen content of the powder determined by the Dume method was 5.72 (±0.2)%. Aqueous and ethanol extracts were obtained from bitter almond powder with a yield of 10.5 and 13.2%. Chromatographic analysis of the composition of the extracts showed the presence of 0.0029% amygdalin in aqueous and 27.2% in ethanol extracts. Protein with a yield of 35.25±0.2% was isolated from the studied powder of bitter almonds. The protein is purified by dialysis, centrifugation and identified by IR spectroscopy. The amino acid analysis of the composition of the hydrolyzate protein of bitter almonds showed the presence of glycine, aspartic acid, arginine, glutamine, alanine and other amino acids. Bitter almond seed powder, extracts and protein isolated from it are of practical interest for cosmetology practice.

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Margolskee, Robert F. "Molecular mechanisms of taste transduction." Pure and Applied Chemistry 74, no. 7 (January 1, 2002): 1125–33. http://dx.doi.org/10.1351/pac200274071125.

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Taste transduction is a specialized form of signal transduction by which taste receptor cells (TRCs) encode at the cellular level information about chemical substances encountered in the oral environment (so-called tastants). Bitter and sweet taste transduction pathways convert chemical information into a cellular second messenger code utilizing cyclic nucleotides, inositol trisphosphate, and/or diacyl glycerol. These messengers are components of signaling cascades that lead to TRC depolarization and Ca++ release. Bitter and sweet taste transduction pathways typically utilize taste-specific or taste-selective seven transmembrane-helix receptors, G proteins, effector enzymes, second messengers, and ion channels. The structural and chemical diversity of tastants has led to the need for multiple transduction mechanisms. Through molecular cloning and data mining, many of the receptors, G proteins, and effector enzymes involved in transducing responses to bitter and sweet compounds are now known. New insights into taste transduction and taste coding underlying sweet and bitter taste qualities have been gained from molecular cloning of the transduction elements, biochemical elucidation of the transduction pathways, electrophysiological analysis of the function of taste cell ion channels, and behavioral analysis of transgenic and knockout models.

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Jeruzal-Świątecka, Joanna, Wojciech Fendler, and Wioletta Pietruszewska. "Clinical Role of Extraoral Bitter Taste Receptors." International Journal of Molecular Sciences 21, no. 14 (July 21, 2020): 5156. http://dx.doi.org/10.3390/ijms21145156.

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Humans can recognise five basic tastes: sweet, sour, salty, bitter and umami. Sour and salty substances are linked to ion channels, while sweet, bitter and umami flavours are transmitted through receptors linked to the G protein (G protein-coupled receptors; GPCRs). There are two main types of GPCRs that transmit information about sweet, umami and bitter tastes—the Tas1r and TAS2R families. There are about 25 functional TAS2R genes coding bitter taste receptor proteins. They are found not only in the mouth and throat, but also in the intestines, brain, bladder and lower and upper respiratory tract. The determination of their purpose in these locations has become an inspiration for much research. Their presence has also been confirmed in breast cancer cells, ovarian cancer cells and neuroblastoma, revealing a promising new oncological marker. Polymorphisms of TAS2R38 have been proven to have an influence on the course of chronic rhinosinusitis and upper airway defensive mechanisms. TAS2R receptors mediate the bronchodilatory effect in human airway smooth muscle, which may lead to the creation of another medicine group used in asthma or chronic obstructive pulmonary disease. The discovery that functionally compromised TAS2R receptors negatively impact glucose homeostasis has produced a new area of diabetes research. In this article, we would like to focus on what facts have been already established in the matter of extraoral TAS2R receptors in humans.

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Wu, Xiao, Takeshi Shiino, Yusuke Tahara, Hidekazu Ikezaki, and Kiyoshi Toko. "Quantification of Pharmaceutical Bitterness Using a Membrane Electrode Based on a Hydrophobic Tetrakis [3,5-Bis (trifluoromethyl) phenyl] Borate." Chemosensors 9, no. 2 (January 31, 2021): 28. http://dx.doi.org/10.3390/chemosensors9020028.

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Technologies for quantifying bitterness are essential for classifying medicines. As previously reported, taste sensors with lipid polymer membranes can respond to bitter hydrochloride substances in pharmaceuticals. However, the acid hydrolysis reaction between the lipid phosphoric acid di-n-decyl ester (PADE) and the plasticizer tributyl o-acetylcitrate (TDAB) led to a deterioration in sensor responses during storage. Given the cost of transportation and preservation for commercialization, membrane components that maintain physical and chemical stability during long-term storage are needed. Here we present a membrane electrode based on hydrophobic tetrakis [3,5-bis (trifluoromethyl) phenyl] borate (TFPB) and a plasticizer 2-nitrophenyl octyl ether (NPOE) for the quantification of pharmaceutical bitterness; they maintain a stable response before and after accelerated deterioration, as well as high selectivity and sensitivity. It is a first attempt to use a completely dissociative substance to replace non-completely dissociative lipids. Our work offsets the long-term stability issue of a bitterness sensor with a negatively charged hydrophobic membrane. Meanwhile, we provide the opportunity to select surface charge modifiers for a membrane surface using ester plasticizers containing oppositely charged impurities.

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Sakurai, Takanobu, Takumi Misaka, Toshitada Nagai, Yoshiro Ishimaru, Shinji Matsuo, Tomiko Asakura, and Keiko Abe. "pH-Dependent Inhibition of the Human Bitter Taste Receptor hTAS2R16 by a Variety of Acidic Substances." Journal of Agricultural and Food Chemistry 57, no. 6 (March 25, 2009): 2508–14. http://dx.doi.org/10.1021/jf8040148.

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10

Gzyra-Jagieła, Karolina, Monika Owczarek, Monika Szkopiecka, Sylwia Jagodzińska, Marzena Dymel, Patrycja Kudra-Miros, and Michał Kudra. "BIODEGRADABLE NONWOVEN ACTIVATED POLYESTER WITH CHITOSAN: POTENTIAL APPLICATION IN THE COSMETIC INDUSTRY." Progress on Chemistry and Application of Chitin and its Derivatives XXV (September 30, 2020): 94–110. http://dx.doi.org/10.15259/pcacd.25.007.

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Textile products enriched with natural substances, e.g. hyaluronic acid, plant hydrolates, collagen and chitosan, may find wide application in cosmetics because of increasing consumer interest in natural products. Furthermore, in view of global environmental pollution, products that are produced through biochemical changes as a result of composting are sought. This makes it possible to enter such designed cosmetic products into the scheme of the currently desired circular economy. Compostable textiles are an ecological alternative to product backlogs and polluting the environment in the form of post-consumer waste. Therefore, this research work developed a technology for applying natural substances on a biodegradable polyester fibrous substrate. This study developed the optimal composition of a mixture consisting of natural substances with properties applicable to the cosmetic industry, for applications such as cosmetic masks to improve the appearance of the skin. The composition of active substances that have beneficial effects on the skin, e.g. moisturizing, regenerating, antibacterial and caring, was determined. The mixture was effectively applied on a spunbound nonwoven substrate of made from aliphatic-aromatic copolyester by impregnation. The employed polymer degraded in a compost environment and its modifiers additionally supported this process. The unique composition of the applied coating layer consisted of a mixture of sodium hyaluronate, collagen, bitter orange blossom hydrolate (Neroli) and chitosan lactate. The coated nonwoven fabric was subjected to physical, mechanical, microbiological as well as chemical purity and structural tests (Fourier transform infrared spectroscopy and scanning electron microscopy) and degree of degradation in a compost environment was assessed on the basis of its weight loss.

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Liu, Xiao, Hui-Ming Fan, Dong-He Liu, Jing Liu, Yan Shen, Jing Zhang, Jun Wei, and Chun-Lei Wang. "Transcriptome and Metabolome Analyses Provide Insights into the Watercore Disorder on “Akibae” Pear Fruit." International Journal of Molecular Sciences 22, no. 9 (May 6, 2021): 4911. http://dx.doi.org/10.3390/ijms22094911.

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Watercore is a physiological disorder that commonly occurs in sand pear cultivars. The typical symptom of watercore tissue is transparency, and it is often accompanied by browning, breakdown and a bitter taste during fruit ripening. To better understand the molecular mechanisms of watercore affecting fruit quality, this study performed transcriptome and metabolome analyses on watercore pulp from “Akibae” fruit 125 days after flowering. The present study found that the “Akibae” pear watercore pulp contained higher sorbitol and sucrose than healthy fruit. Moreover, the structure of the cell wall was destroyed, and the content of pectin, cellulose and hemicellulose was significantly decreased. In addition, the content of ethanol and acetaldehyde was significantly increased, and the content of polyphenol was significantly decreased. Watercore induced up-regulated expression levels of sorbitol synthesis-related (sorbitol-6-phosphate dehydrogenase, S6PDH) and sucrose synthesis-related genes (sucrose synthesis, SS), whereas it inhibited the expression of sorbitol decomposition-related genes (sorbitol dehydrogenase, SDH) and sorbitol transport genes (sorbitol transporter, SOT). Watercore also strongly induced increased expression levels of cell wall-degrading enzymes (polygalactosidase, PG; ellulase, CX; pectin methylesterase, PME), as well as ethanol synthesis-related (alcohol dehydrogenase, ADH), acetaldehyde synthesis-related (pyruvate decarboxylase, PDC) and polyphenol decomposition-related genes (polyphenol oxidase, PPO). Moreover, the genes that are involved in ethylene (1-aminocyclopropane- 1-carboxylate oxidase, ACO; 1-aminocyclopropane- 1-carboxylate synthase, ACS) and abscisic acid (short-chain alcohol dehydrogenase, SDR; aldehyde oxidase, AAO) synthesis were significantly up-regulated. In addition, the bitter tasting amino acids, alkaloids and polyphenols were significantly increased in watercore tissue. Above all, these findings suggested that the metabolic disorder of sorbitol and sucrose can lead to an increase in plant hormones (abscisic acid and ethylene) and anaerobic respiration, resulting in aggravated fruit rot and the formation of bitter substances.

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Chen, Zhongliang, Zhong-liang Chen, Ji-hui Shen, and Yi-sheng Gao. "Some Chemical Reactions of Taccalonoide A - a Bitter Substance from Tacca plantaginea." HETEROCYCLES 29, no. 11 (1989): 2103. http://dx.doi.org/10.3987/com-89-5101.

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Okahata, Yoshio, Genichiro Enna, and Hiroshi Ebato. "Synthetic chemoreceptive membranes. Sensing bitter or odorous substances on a synthetic lipid multibilayer film by using quartz-crystal microbalances and electric responses." Analytical Chemistry 62, no. 14 (July 15, 1990): 1431–38. http://dx.doi.org/10.1021/ac00213a017.

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Chuang, Lu-Te, Ya-Hsin Shih, Wen-Cheng Huang, Lie-Chwen Lin, Chin Hsu, Jong-Ho Chyuan, Tsung-Hsien Tsai, and Po-Jung Tsai. "In Vitro and In Vivo Screening of Wild Bitter Melon Leaf for Anti-Inflammatory Activity against Cutibacterium acnes." Molecules 25, no. 18 (September 18, 2020): 4277. http://dx.doi.org/10.3390/molecules25184277.

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Cutibacterium acnes (formerly Propionibacterium acnes) is a key pathogen involved in the development and progression of acne inflammation. The numerous bioactive properties of wild bitter melon (WBM) leaf extract and their medicinal applications have been recognized for many years. In this study, we examined the suppressive effect of a methanolic extract (ME) of WBM leaf and fractionated components thereof on live C. acnes-induced in vitro and in vivo inflammation. Following methanol extraction of WBM leaves, we confirmed anti-inflammatory properties of ME in C. acnes-treated human THP-1 monocyte and mouse ear edema models. Using a bioassay-monitored isolation approach and a combination of liquid–liquid extraction and column chromatography, the ME was then separated into n-hexane, ethyl acetate, n-butanol and water-soluble fractions. The hexane fraction exerted the most potent anti-inflammatory effect, suppressing C. acnes-induced interleukin-8 (IL-8) production by 36%. The ethanol-soluble fraction (ESF), which was separated from the n-hexane fraction, significantly inhibited C. acnes-induced activation of mitogen-activated protein kinase (MAPK)-mediated cellular IL-8 production. Similarly, the ESF protected against C. acnes-stimulated mouse ear swelling, as measured by ear thickness (20%) and biopsy weight (23%). Twenty-four compounds in the ESF were identified using gas chromatograph–mass spectrum (GC/MS) analysis. Using co-cultures of C. acnes and THP-1 cells, β-ionone, a compound of the ESF, reduced the production of IL-1β and IL-8 up to 40% and 18%, respectively. β-ionone also reduced epidermal microabscess, neutrophilic infiltration and IL-1β expression in mouse ear. We also found evidence of the presence of anti-inflammatory substances in an unfractionated phenolic extract of WBM leaf, and demonstrated that the ESF is a potential anti-inflammatory agent for modulating in vitro and in vivo C. acnes-induced inflammatory responses.

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Mazur, Monika, Anna Marietta Salejda, Kinga Maria Pilarska, Grażyna Krasnowska, Agnieszka Nawirska-Olszańska, Joanna Kolniak-Ostek, and Przemysław Bąbelewski. "The Influence of Viburnum opulus Fruits Addition on Some Quality Properties of Homogenized Meat Products." Applied Sciences 11, no. 7 (April 1, 2021): 3141. http://dx.doi.org/10.3390/app11073141.

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This review describes the effect of added freeze-dried guelder rose fruit powder (GRFP) on the quality parameter of homogenized meat products (HMP). In this study, the pH, cooking loss, instrumental color (L*, a* and b*), texture profile, TBARS (Thiobarbituric acid reactive substances), antimicrobial assay, polyphenol content and sensory evaluation of HMP were evaluated. Due to the antioxidant activity of guelder rose fruit (the chlorogenic acid dominated among the identified compounds of the fruit), it was observed that, in the samples with the highest amount of the extract, the amount of microorganisms responsible for food spoilage decreased after storage time (14 days, 4 °C). The addition of lyophilized fruits with a low pH value resulted in the highest cooking loss. The results of sensory evaluation show that, along with the increase of GRFP addition, the taste and smell of meat products become less acceptable. The bitter taste of guelder rose fruit can affect the sensory assessment of meat products. This study is of a pilot nature; further research attempts will be made to offset the problems and design certain solutions, e.g., the use of freeze-dried encapsulation and its addition to meat products.

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Yata, Terumasa, and Kazuo Nomura. "Transient Membrane Potential in Response to a Bitter Substance in a Membrane Filter Impregnated with Phospholipid and 1-Octanol." Bulletin of the Chemical Society of Japan 71, no. 11 (November 1998): 2589–95. http://dx.doi.org/10.1246/bcsj.71.2589.

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Haddad, Moawiya A., Jafar El-Qudah, Saeid Abu-Romman, Maher Obeidat, Candela Iommi, and Da’san M. M. Jaradat. "Phenolics in Mediterranean and Middle East Important Fruits." Journal of AOAC INTERNATIONAL 103, no. 4 (May 3, 2020): 930–34. http://dx.doi.org/10.1093/jaocint/qsz027.

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Abstract Background Phenolic compounds (polyphenols) are common plant secondary metabolites playing different roles in plants, and some of these vegetables and correlated fruits—figs, grapes, pomegranates, olives, date palms, etc.—contain remarkable and diversified amounts of these substances. In addition, polyphenols are reported to show positive effects for human health, because of their antioxidant behavior. Figs are an excellent source of polyphenols with highest concentrations of proanthocyanidins. Actually, figs contain higher amounts of polyphenols than red wine and tea. Objective Antioxidant activity of several flavonoids (a group of polyphenols) in figs is higher than that of, vitamin C, glutathione, or vitamin E. Pomegranates contain very high levels of polyphenols as compared to other fruits and vegetables. It is used in folklore medicine for the treatment of various diseases, such as hepatic damage, snakebite, ulcer, etc. Method The health-positive potential of pomegranate fruit has been mainly attributed to ellagitannins, the predominant class of phenolics in pomegoxidation. Results The chief phenolic compound found in fresh olive is the bitter secoiridoid oleuropein.. Conclusions Processing of table olive decreases levels of oleuropein with correlated increases in the hydrolysis of hydroxytyrosol and tyrosol. Many of the health benefits reported for olives are thought to be associated with the levels of hydroxytyrosol. Date palm represents a staple food in most of the Arabian countries and is commonly consumed in several parts of the world. Highlights Numerous researches revealed the antibacterial, anti-hyperlipidemic, hepatoprotective, antimutagenic, and nephroprotective activity of date fruits, with reported anticancer and anti-fungal features.

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Horie, Masao, Mitsuo Oishi, Fusako Ishikawa, Tetsuya Shindo, Akiko Yasui, Shuzo Ogino, and Koichi Ito. "Liquid Chromatographic Analysis of Cinchona Alkaloids in Beverages." Journal of AOAC INTERNATIONAL 89, no. 4 (July 1, 2006): 1042–47. http://dx.doi.org/10.1093/jaoac/89.4.1042.

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Abstract A method for the determination of Cinchona extract (whose main components are the alkaloids cinchonine, cinchonidine, quinidine, and quinine) in beverages by liquid chromatography was developed. A beverage with an alcohol content of more than 10% was loaded onto an OASIS HLB solid-phase extraction cartridge, after it was adjusted to pH 10 with 28% ammonium hydroxide. Other beverages were centrifuged at 4000 rpm for 5 min, and the supernatant was loaded onto the cartridge. The cartridge was washed with water followed by 15% methanol, and the Cinchona alkaloids were eluted with methanol. The Cinchona alkaloids in the eluate were chromatographed on an L-column ODS (4.6 mm id × 150 mm) with methanol and 20 mmol/L potassium dihydrogen phosphate (3 + 7) as the mobile phase. Cinchona alkaloids were monitored with an ultraviolet (UV) detector at 230 nm, and with a fluorescence detector at 405 nm for cinchonine and cinchonidine and 450 nm for quinidine and quinine (excitation at 235 nm). The calibration curves for Cinchona alkaloids with the UV detector showed good linearity in the range of 2400 μg/mL. The detection limit of each Cinchona alkaloid, taken to be the concentration at which the absorption spectrum could be identified, was 2 μg/mL. The recovery of Cinchona alkaloids added at a level of 100 μg/g to various kinds of beverages was 87.6-96.5%, and the coefficients of variation were less than 3.3%. A number of beverage samples, some labeled to contain bitter substances, were analyzed by the proposed method. Quinine was detected in 2 samples of carbonated beverage.

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Feng, Shiling, Chunyan Zhang, Li Liu, Zhou Xu, Tao Chen, Lijun Zhou, Ming Yuan, Tian Li, and Chunbang Ding. "Comparison of Phenolic Compounds in Olive Leaves by Different Drying and Storage Methods." Separations 8, no. 9 (September 17, 2021): 156. http://dx.doi.org/10.3390/separations8090156.

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Oleuropein, a bitter substance that exists in olive leaves, can be hydrolyzed to hydroxytyrosol. These are the main phenolic compounds, and they have beneficial properties to human bodies. In this study, we established a simple and new method to determine oleuropein and hydroxytyrosol quickly by HPLC. HPLC conditions were set as follows: water (A) acetonitrile (B) as mobile phase, gradient elution orders: 90%A–10%B for 0–10 min, 80%A–20%B for 14–30 min, and then change to 90%A–10%B for 30–33 min; detection wavelength: 280 nm. Compared with other detection methods, the method simplified the elution procedure and shortened the time. Additionally, we provided a better drying method and preservation of olive leaves in tea drinking production that were air-dried at room temperature of 25 °C.

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Rhyu, Mee-Ra, Yiseul Kim, and Vijay Lyall. "Interactions between Chemesthesis and Taste: Role of TRPA1 and TRPV1." International Journal of Molecular Sciences 22, no. 7 (March 25, 2021): 3360. http://dx.doi.org/10.3390/ijms22073360.

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In addition to the sense of taste and olfaction, chemesthesis, the sensation of irritation, pungency, cooling, warmth, or burning elicited by spices and herbs, plays a central role in food consumption. Many plant-derived molecules demonstrate their chemesthetic properties via the opening of transient receptor potential ankyrin 1 (TRPA1) and transient receptor potential vanilloid 1 (TRPV1) channels. TRPA1 and TRPV1 are structurally related thermosensitive cation channels and are often co-expressed in sensory nerve endings. TRPA1 and TRPV1 can also indirectly influence some, but not all, primary taste qualities via the release of substance P and calcitonin gene-related peptide (CGRP) from trigeminal neurons and their subsequent effects on CGRP receptor expressed in Type III taste receptor cells. Here, we will review the effect of some chemesthetic agonists of TRPA1 and TRPV1 and their influence on bitter, sour, and salt taste qualities.

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IBRAKOVA, Nurgiza F., Galiya G. KUTLUGILDINA, and Yuriy S. ZIMIN. "COMPLEXATION OF PRAZIQUANTEL WITH α-, β- AND y-CYCLODEXTRINS IN AQUEOUS-ALCOHOLIC SOLUTIONS." Periódico Tchê Química 17, no. 36 (December 20, 2020): 302–14. http://dx.doi.org/10.52571/ptq.v17.n36.2020.317_periodico36_pgs_302_314.pdf.

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Currently, the percentage of infections with invasive (parasitic) diseases is quite large; therefore, the treatment of helminthiases is an urgent problem in veterinary medicine. Parasitic worms inflict significant damage on animal husbandry, leading to the death of animals, shortage of meat, dairy products, and wool. The most common active ingredient in antihelmintics is praziquantel, which is well known as an effective broad-spectrum anthelmintic. At the same time, praziquantel has low solubility in water and a pronounced bitter taste, which represents a significant obstacle in developing liquid forms of drugs that are convenient for administration to animals. One way to solve these problems is the complexation of medicinal substances with various (natural and synthetic) compounds. In this regard, this paper aims to study the complexation of praziquantel with α-, β-, and -cyclodextrins in aqueous-alcoholic solutions. The studies were carried out by the method of ultraviolet spectroscopy. It was found that the addition of cyclodextrins to aqueous-alcoholic solutions of praziquantel leads to spectral changes indicating the presence of intermolecular interactions and complexation. The isomolar series method showed that in dilute solutions, praziquantel forms complex compounds with cyclodextrins 1:1, that is, one molecule of praziquantel falls on one molecule of α-, β- or y-cyclodextrin. The stability constants of the resulting complexes were calculated using the molar ratio method. It is shown that in the range of 296-316 K, the composition of complex compounds remains unchanged (1:1), and their stability decreases with increasing temperature. The study of the temperature dependences of the stability constants made it possible to determine the standard values of changes in the Gibbs energy, enthalpy, and complexation entropy.

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Issaoui, Manel, Amélia Martins Delgado, Giorgia Caruso, Maria Micali, Marcella Barbera, Hager Atrous, Amira Ouslati, and Nadia Chammem. "Phenols, Flavors, and the Mediterranean Diet." Journal of AOAC INTERNATIONAL 103, no. 4 (June 4, 2020): 915–24. http://dx.doi.org/10.1093/jaocint/qsz018.

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Abstract Phenols or phenolics are a class of compounds that have one or more hydroxyl groups attached to a 6-carbon aromatic ring, they occur as plant secondary metabolites, having in common the antioxidant activity. Their average daily intake varies widely around the world. Many researchers consider coffee, tea, wine, cocoa products, fruits and vegetables as the main sources of polyphenols in different diets. However, spices and culinary herbs have been referred to as the foods richest in polyphenols. Despite spices and culinary herbs are used in small amounts as seasonings, their contribution to the dietary supply of phytonutrients should not be disregarded. A diet rich in a variety of polyphenols (and other phytonutrients) has potential health benefits, namely in the prevention of chronic diseases and cancer. In addition, flavor and color are the most important factors for the selection of food by consumers. A multitude of endogenous food compounds, including phenolics, are involved in food flavor. The presence of phenolic compounds in the food matrix has been mainly associated with the perception of bitter taste and tactile sensation of astringency. However, these compounds can also impact the color and aroma notes of fruits and vegetables. Thus, understanding the sensory impact of these substances and relationships with consumers’ approaches towards phenolic-rich fruits and vegetables may help find strategies to increase the consumption of such foods. A well-known example of a tasty, healthy and sustainable dietary model is the Mediterranean Diet. In this study, we summarize the dietary intake of some polyphenols from different dietary patterns around the world and the contribution of natural phenolic compounds to the flavor of food and beverages, in particularly those associated to the Mediterranean Diet.

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Dyakova, Nina Alekseyevna, Aleksey Ivanovich Slivkin, Yelena Yevgen'yevna Chupandina, and Sergey Petrovich Gaponov. "IDENTIFICATION OF PERMISSIBLE AREAS OF PREPARATION OF MEDICINAL VEGETABLE RAW MATERIALS NEAR TRANSPORT LINES." chemistry of plant raw material, no. 4 (December 21, 2020): 179–86. http://dx.doi.org/10.14258/jcprm.2020047609.

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The purpose of the work is to study the permissible distance for the collection of medicinal plant raw materials near transport highways of different degrees of loading. The study was carried out in the Voronezh region on the example of eight different types of medicinal vegetable raw materials (Herring grass bitter, avian mountain grass, five-foot desert grass, plain thousand-year-old grass, double-ground nettle leaves, large planter leaves, common pajma flowers, core lip flowers) Collected in time of procurement along and at different distance from roads and railways of different degree of load in different natural zones, regulated by normative documentation. In the analyzed samples, the content of standardized biologically active substances, as well as heavy metals, pesticides, radionuclides, was previously estimated and full compliance with pharmacopoeia requirements was shown. In this work, the analysis was carried out on the level of ash insoluble in hydrochloric acid in the medicinal plant raw material, which makes it possible to estimate contamination of the raw material with dust particles. On the basis of the obtained data using the mathematical simulation method, the permissible distances from the transport lines, which can be recommended for the collection of safe medicinal plant raw materials, have been identified: Distance from major roads and highways loaded by road in forest natural zone conditions – at least 230 m, in forest steppe zone conditions – at least 300 m, in steppe zone conditions devoid of wood and shrub vegetation, – Not less than 660 m, near non-high-speed roads characterized by low traffic load – not less than 160 m, near railway lines – not less than 130 m. The obtained results can be recommended for safe collection of medicinal vegetable raw materials.

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David, Sofia, Anton Knieling, Simona Irina Damian, Madalina Diac, Ion Sandu, and Tatiana Iov. "Study on Forms of Intoxication with Cocaine and Evolutionary Aspects." Revista de Chimie 69, no. 5 (June 15, 2018): 1216–19. http://dx.doi.org/10.37358/rc.18.5.6292.

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Cocaine is an alkaloid obtained from the leaves of the coca plant, Erythroxylum coca. Cocaine sulfate, a brown paste, is obtained from coca leaves and from this, cocaine hydrochloride, a white substance, soluble in water and with a bitter taste that may be in the form of white crystals or powder. From cocaine hydrochloride crack is obtained by heating, a more purified form and with greater power of intoxication and addiction. Once in the organism, cocaine behaves like an indirect sympathomimetic amine and produces a blockade of the presynaptic reuptake of dopamine, adrenaline, noradrenaline and serotonin, thus increasing their levels. At the cardiovascular level cocaine is responsible for malignant arrhythmias, sometimes responsible for sudden death. Other symptoms that can occur are aortic dissection, arterial hypertension and coronary vasoconstriction able to trigger an acute myocardial infarction. The authors present a case of sudden cardiac death due to cocaine intoxication in a young male without any cardiac risk factors. The autopsy, together with the results of the complementary tests, indicate that the most probable death mechanism has been a cardiogenic shock secondary to extensive myocardial necrosis due to cocaine intoxication.

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Kurihara, Kenzo, Yoshihisa Katsuragi, Ichiro Matsuoka, Makoto Kashiwayanagi, Takashi Kumazawa, and Takayuki Shoji. "Receptor mechanisms of bitter substances." Physiology & Behavior 56, no. 6 (December 1994): 1125–32. http://dx.doi.org/10.1016/0031-9384(94)90356-5.

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TANIMURA, SHUYA, and RICHARD D. MATTES. "RELATIONSHIPS BETWEEN BITTER TASTE SENSITIVITY AND CONSUMPTION OF BITTER SUBSTANCES." Journal of Sensory Studies 8, no. 1 (March 1993): 31–41. http://dx.doi.org/10.1111/j.1745-459x.1993.tb00200.x.

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Liashenko, M., L. Protsenko, R. Rudyk, and O. Svirchevska. "Bitter Substances in the Hop Lupulin." Agricultural Science and Practice 1, no. 1 (April 15, 2014): 20–25. http://dx.doi.org/10.15407/agrisp1.01.020.

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Aim. To investigate the quantity and structure of α-, β-acids and xanthohumol in lupulin grains of different hop varieties that essentially differ in these biochemical indexes, and also the presence of the substances both in staminate racemes and in the leaves. Methods. High performance liquid chromatography (HPLC), up-to- date physical-chemical methods of hop quality indicators’ defi nition, special and standard in the hop-growing branch, were applied. Results. It was stated that lupulin of aroma and bitter varieties contains various quantity of α- and β-acids. Therefore, the ratio of α- to β-acids in aroma hop varieties is above one (1), whereas in varieties of bitter type this ratio is much lower than one (1). No correlation between the quantity of lupulin and the contents of α- and β-acids was found. It was noted that the color of lupulin depends upon the quantity of xanthohumol. Conclusions. The performed tests give evidences on lupulin glands are located on anthers of staminate racemes and on the leaves as well, though in much less quantity and less educed. It was found that the quantity and structure of bitter substances in lupulin grains from selection varieties does not depend upon lupulin content in hop cones, but it is a grading factor. Lupulin from the staminate racemes received from various plants essentially differs in quantity of α- and β-acids. This fact is of key importance for pair selection. In petal glands on the leaves of a hop plant bitter substances are represented only by β-acids, mainly lupulone and adlupulone.

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Rezaie, Peyman, Vida Bitarafan, Michael Horowitz, and Christine Feinle-Bisset. "Effects of Bitter Substances on GI Function, Energy Intake and Glycaemia-Do Preclinical Findings Translate to Outcomes in Humans?" Nutrients 13, no. 4 (April 16, 2021): 1317. http://dx.doi.org/10.3390/nu13041317.

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Bitter substances are contained in many plants, are often toxic and can be present in spoiled food. Thus, the capacity to detect bitter taste has classically been viewed to have evolved primarily to signal the presence of toxins and thereby avoid their consumption. The recognition, based on preclinical studies (i.e., studies in cell cultures or experimental animals), that bitter substances may have potent effects to stimulate the secretion of gastrointestinal (GI) hormones and modulate gut motility, via activation of bitter taste receptors located in the GI tract, reduce food intake and lower postprandial blood glucose, has sparked considerable interest in their potential use in the management or prevention of obesity and/or type 2 diabetes. However, it remains to be established whether findings from preclinical studies can be translated to health outcomes, including weight loss and improved long-term glycaemic control. This review examines information relating to the effects of bitter substances on the secretion of key gut hormones, gastric motility, food intake and blood glucose in preclinical studies, as well as the evidence from clinical studies, as to whether findings from animal studies translate to humans. Finally, the evidence that bitter substances have the capacity to reduce body weight and/or improve glycaemic control in obesity and/or type 2 diabetes, and potentially represent a novel strategy for the management, or prevention, of obesity and type 2 diabetes, is explored.

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Popoviciu, Dan Razvan, Ticuta Negreanu-Pirjol, Ludmila Motelica, and Bogdan-Stefan Negreanu-Pirjol. "Carotenoids, Flavonoids, Total Phenolic Compounds Content and Antioxidant Activity of Indigenous Pyracantha coccinea M. Roem. Fruits." Revista de Chimie 71, no. 4 (May 5, 2020): 258–66. http://dx.doi.org/10.37358/rc.20.4.8064.

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Scarlet/red firethorn, Pyracantha coccinea M. Roem., is a common ornamental shrub, commonly cultivated nowadays in Romania and many other countries, in gardens or hedges. The tree has small white flowers and it produces small bright colored berries. The fruit is bitter and astringent, making it inedible when raw. The fruit can be cooked to make jellies, jams, sauces and marmalade. In this study, the Pyracantha coccinea M. Roem fruits from three common cultivars named �Orange Glow�, �Red Column� and �Soleil d�Or�, were collected from different individuals in Constanta city, Romania. Both frozen and dried (80�C) fruits were analyzed for the active principles content such as, carotenoids, flavonoids and total phenolic compounds correlated with antioxidant activity. Carotenoids were determined by acetone extraction and UV-Vis spectrophotometry, flavonoids, by methanol extraction and UV-Vis spectrophotometry and total phenolic, by methanol extraction, Folin-Ciocalteu reaction and UV-Vis spectrophotometry. The total antioxidant capacity was quantified through photochemiluminescence method by comparison with the standard substance used for calibration, Trolox� as tocopherol analogue (ACL procedure) using Photochem apparatus, Analytik Jena AG, Germany. The average carotenoid content in fresh frozen fruits ranged between 278-545 mg/kg (dry weight equivalent), while in dry material 133-203 mg/kg. Total flavonoids averaged 1415-4953 mg/kg in fresh fruits, increasing after heat-drying to 2981-5759 mg/kg. Fresh fruits contained a total amount of phenolic compounds of 11501-21107 mg/kg DW gallic acid equivalent, while dry fruits averaged 5749-8261 mg/kg GAE. Pyracantha coccinea M. Roem. fruits emphasized an increased antioxidant activity correlated with a high content of potentially bioactive compounds, especially of phenolic compounds, both in frozen and heat-dried state. �Red Column� and �Orange Glow� are the most promising varieties of the three cultivars, for potential pharmaceutical applications.

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Yokomukai, Yoshiko, Beverly J. Cowart, and Gary K. Beauchamp. "Individual differences in sensitivity to bitter-tasting substances." Chemical Senses 18, no. 6 (1993): 669–81. http://dx.doi.org/10.1093/chemse/18.6.669.

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Frijters, Jan E. R., and Hendrik N. J. Schifferstein. "Perceptual interactions in mixtures containing bitter tasting substances." Physiology & Behavior 56, no. 6 (December 1994): 1243–49. http://dx.doi.org/10.1016/0031-9384(94)90372-7.

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WU, CHUNSHENG, LIPING DU, LIHUI MAO, and PING WANG. "A NOVEL BITTER DETECTION BIOSENSOR BASED ON LIGHT ADDRESSABLE POTENTIOMETRIC SENSOR." Journal of Innovative Optical Health Sciences 05, no. 02 (April 2012): 1250008. http://dx.doi.org/10.1142/s1793545812500083.

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This paper presents a novel biosensor for bitter substance detection on the basis of light addressable potentiometric sensor (LAPS). Taste receptor cells (TRCs) were used as sensitive elements, which can respond to different bitter stimuli with extreme high sensitivity and specificity. TRCs were isolated from the taste buds of rats and cultured on the surface of LAPS chip. Due to the unique advantages such as single-cell recording, light addressable capability, and noninvasiveness, LAPS chip was used as secondary transducer to monitor the responses of TRCs by recording extracelluar potential changes. The results indicate LAPS chip can effectively record the responses of TRCs to different bitter substances used in this study in a real-time manner for a long-term. In addition, by performing principal component analysis on the LAPS recording data, different bitter substances tested can be successfully discriminated. It is suggested this TRCs–LAPS hybrid biosensor could be a valuable tool for bitter substance detection. With further improvement and novel design, it has great potentials to be applied in both basic research and practical applications related to bitter taste detection.

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Protsenko, L., M. Liashenko, A. Vlasenko, T. Hryniuk, and O. Dobrovolny. "Investigation of properties of biologically active substances and their content in cones of ukrainian hop varieties." Agricultural Science and Practice 5, no. 2 (July 15, 2018): 52–63. http://dx.doi.org/10.15407/agrisp5.02.052.

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Introduction. According to the data of foreign studies, prenyl fl avonoids and bitter substances of hop have signifi cant antioxidant, antiviral, antimicrobial, anti-infl ammatory and anti-carcinogenic properties. Methods. A complex of the following methods was used: a monographic method, analysis, synthesis and comparison, mathematical-statistical and modern physical-chemical methods of determining qualitative indices of hop, special and common in hop-growing industry, which allowed obtaining scientifi cally valid results. Results. The modern level of knowledge about biologically active compounds of hop and their properties was analyzed, in particular, bitter substances and xanthohumol. The quantitative and qualitative content of bitter substances, essential oil and xanthohumol in hop varieties of Ukrainian, European and American breeding was studied. Among the Ukrainian varieties, the highest amount of xanthohumol was found in Ruslan and Xanthus varie- ties – 1.16 % and 1.06 % against dry substances respectively, and its minimal amount was detected in the cones of the bitter Alta variety. Among the European varieties, the highest amount of this substance is contained in the German variety HallertauerTaurus – 0.9–1.0 %, up to 1 % in the Czech variety Agnus and the English va- riety Admiral, with the content of 0.95 %–1.09 %. There is a strong correlation between the accumulation of xanthohumol and alpha acids in the formation and ripening of the cones. The maximal amount of xanthohumol is formed in the hop cones in the phase of complete technical ripeness. The content of this substance in hop cones depends on the breeding variety and is a varietal trait, genetically fi xed for each variety. The quantitative amount of xanthohumol may be one of biochemical criteria of identifying the variety. Conclusions. By their characteristics, the Ukrainian hop varieties correspond to the world’s analogues, namely, according to their bio- chemical and technological indices, hop varieties Klon-18 and Zlato Polissia correspond to the characteristics of the hop of the Czech Saaz variety, the biochemical indices of the bitter Alta variety correspond to the Ger- man variety Magnum, and such varieties as Slovianka and Zahrava exceed the world’s analogues considerably in the composition and quality of bitter substances and essential oils and are unique.

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Oami, K. "Membrane potential responses of paramecium caudatum to bitter substances: existence of multiple pathways for bitter responses." Journal of Experimental Biology 201, no. 1 (January 1, 1998): 13–20. http://dx.doi.org/10.1242/jeb.201.1.13.

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The membrane potential responses of Paramecium caudatum to the external application of bitter substances were examined by employing conventional electrophysiological techniques. Mutant cells defective in voltage-gated Ca2+ channels were used to record the potential responses in the absence of contamination by Ca2+ action potentials. The cells produced a transient depolarization followed by a transient hyperpolarization in response to a rapid whole-cell application of chloroquine, strychnine nitrate or brucine. Of these chemicals, chloroquine was the most potent. Cells produced a simple depolarization in response to a localized application of test chemicals to the anterior region, whereas they produced a transient hyperpolarization in response to an application to the posterior region. Membrane potential responses to an application of chloroquine declined with repeated application. The presence of chloroquine in the external bathing solution strongly inhibited the membrane potential responses to an application of brucine or strychnine. However, the presence of chloroquine did not affect the membrane potential responses to an application of quinine. It is suggested that chloroquine, strychnine and brucine share a common component of their transduction pathways, but that the transduction pathway for quinine is different.

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Procházka, Pavel, Přemysl Štranc, Kateřina Pazderů, Jan Vostřel, and Jan Řehoř. "Use of biologically active substances in hops." Plant, Soil and Environment 64, No. 12 (November 30, 2018): 626–32. http://dx.doi.org/10.17221/655/2018-pse.

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In four-year experiments, hop was treated with 7 biologically active substances in two terms during vegetation: Lignohumate max (a mixture of humic acids and fulvic acids), Lexin (a mixture of humic acids and fulvic acids enriched with auxins), Lexenzym (a mixture of humic acids and fulvic acids enriched with auxins, phytohormones and enzymes precursors), Ascophyllum nodosum seaweed extract, synthetic auxin, humic acids and fulvic acids alone. The chlorophyll content was monitored after the application both in the vine leaves and in the branch leaves. After harvesting of the hops from the individual treatments, the yield of dry hops was determined and the cones were analysed for the content of alpha bitter acids. The results show that the most effective hop treatment was the application of Lexin and Lexenzym. The Lexenzym treatment provided a yield of dry hops of 1.86 t/ha, i.e. 0.47 t/ha higher compared with untreated control. The Lexin treatment provided yield higher by 0.41 t/ha of dry hops compared with the untreated control, while the harvested cones contained the most alpha-bitter acids (4.57%).

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Katsuragi, Yoshihisa, Takeshi Yasumasu, and Kenzo Kurihara. "Lipoprotein that selectively inhibits taste nerve responses to bitter substances." Brain Research 713, no. 1-2 (March 1996): 240–45. http://dx.doi.org/10.1016/0006-8993(95)01541-8.

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Sambu, Sammy. "The determinants of chemoreception as evidenced by gradient boosting machines in broad molecular fingerprint spaces." PeerJ Organic Chemistry 1 (December 3, 2019): e2. http://dx.doi.org/10.7717/peerj-ochem.2.

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The ability to identify and reject bitter molecules may determine evolutionary fitness. These molecules might be in potentially toxic or contaminated food. Surprisingly, the ability to identify but tolerate or even enjoy bitter foods and medicines may be beneficial. For example, the tolerance of bitterness as a spice or as a medicine may lead to better nutritional, immunological and health outcomes. More recently the ability of intensely bitter compounds to induce innate immune responses to counter infection has inspired the screening of new drugs and the repurposing of safe, known drugs to new uses. These avenues of study may also help to address long-standing questions regarding unexpected side-effects and placebo/nocebo effects. Therefore, to distinguish all these effects ranging from desire to aversion, there is a need to quantitatively determine the concentration thresholds and to position these bitter substances on a unified taste threshold spectrum. Such an understanding may help elucidate the concentration-based molecular drivers for the chemoreceptive response to bitter substances. This article reports the development of a gradient boosting machine (GBM) that enables a direct interrogation of molecular structure with no intermediary chemical properties. Using molecularly engineered simulations, it is shown that potassium acesulfame has a hidden bitterness motif that is centered on the chemoreceptive spectrum uniting bitterness and sweetness molecular motifs. The resultant shifted perception from a touchstone bitterness sensation to a bitter after-taste is attributable to this cached molecular motif.

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Behrens, Maik, Ming Gu, Shengjie Fan, Cheng Huang, and Wolfgang Meyerhof. "Bitter substances from plants used in traditional Chinese medicine exert biased activation of human bitter taste receptors." Chemical Biology & Drug Design 91, no. 2 (September 14, 2017): 422–33. http://dx.doi.org/10.1111/cbdd.13089.

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Naim, M., R. Seifert, B. Nürnberg, L. Grünbaum, and G. Schultz. "Some taste substances are direct activators of G-proteins." Biochemical Journal 297, no. 3 (February 1, 1994): 451–54. http://dx.doi.org/10.1042/bj2970451.

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Amphiphilic substances may stimulate cellular events through direct activation of G-proteins. The present experiments indicate that several amphiphilic sweeteners and the bitter tastant, quinine, activate transducin and Gi/Go-proteins. Concentrations of taste substances required to activate G-proteins in vitro correlated with those used to elicit taste. These data support the hypothesis that amphiphilic taste substances may elicit taste through direct activation of G-proteins.

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OLESIŃSKA, KATARZYNA. "Sesquiterpene lactones – occurrence and biological properties. A review." Agronomy Science 73, no. 3 (November 29, 2018): 83–95. http://dx.doi.org/10.24326/asx.2018.3.7.

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Sesquiterpene lactones are secondary metabolites commonly found in higher plants as well as mosses, lichens, and fungi. Currently, over 5000 of such compounds have been identified with a majority isolated from Asteraceae plants. They are characterised by different chemical structures associated with the presence of various carbon pathways and functional groups, which exert an impact on their pharmacological activity. These colourless substances are soluble in fats, alcohols, or water. They are often bitter ingredients regarded as bitter compounds. They are accumulated mainly in leaves, flower parts and seeds; less frequently, they are present in roots. Sesquiterpene lactones exhibit multidirectional biological activity: some of them have anticancer, anti-inflammatory, antidiabetic, analgesic, antiparasitic, antifungal, and bacteriostatic effects. Therefore, high hopes are placed on the medical and pharmaceutical use of these substances. Lactone compounds are also regarded as a potential source of new active substances used in agriculture to combat plant pathogens

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Spielman, A. I., H. Nagai, G. Sunavala, M. Dasso, H. Breer, I. Boekhoff, T. Huque, G. Whitney, and J. G. Brand. "Rapid kinetics of second messenger production in bitter taste." American Journal of Physiology-Cell Physiology 270, no. 3 (March 1, 1996): C926—C931. http://dx.doi.org/10.1152/ajpcell.1996.270.3.c926.

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The tasting of bitter compounds may have evolved as a protective mechanism against ingestion of potentially harmful substances. We have identified second messengers involved in bitter taste and show here for the first time that they are rapid and transient. Using a quench-flow system, we have studied bitter taste signal transduction in a pair of mouse strains that differ in their ability to taste the bitter stimulus sucrose octaacetate (SOA); however, both strains taste the bitter agent denatonium. In both strains of mice, denatonium (10 mM) induced a transient and rapid increase in levels of the second messenger inositol 1,4,5-trisphosphate (IP3) with a maximal production near 75-100 ms after stimulation. In contrast, SOA (100 microM) brought about a similar increase in IP3 only in SOA-taster mice. The response to SOA was potentiated in the presence of GTP (1 microM). The GTP-enhanced SOA-response supports a G protein-mediated response for this bitter compound. The rapid kinetics, transient nature, and specificity of the bitter taste stimulus-induced IP3 formation are consistent with the role of IP3 as a second messenger in the chemoelectrical transduction of bitter taste.

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Sakurai, Hidetoshi, Hidenori Koga, Gaku Ishikawa, Tatsuo Endo, Chinami Matsuyama, Tomohiro Yano, Naoko Ohta, Hitomi Kumagai, Huong Thi Thu Nguyen, and Jan Pokorny. "Formation of bitter substances in solutions containing vitamin C and aspartame." International Congress Series 1245 (November 2002): 383–85. http://dx.doi.org/10.1016/s0531-5131(02)01014-2.

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Naito, M., N. Sasaki, and T. Kambara. "Mechanism of the electric response of lipid bilayers to bitter substances." Biophysical Journal 65, no. 3 (September 1993): 1219–30. http://dx.doi.org/10.1016/s0006-3495(93)81159-7.

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KROFTA, K., A. RÍGR, F. KROUPA, and F. BERÁNEK. "Bitter substances and essential oils analyses of hop hybrid new selections." Kvasny Prumysl 42, no. 7 (July 1, 1996): 237–340. http://dx.doi.org/10.18832/kp1996016.

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Okahata, Yoshio, Hiroshi Ebato, and Kazuhiro Taguchi. "Specific adsorption of bitter substances on lipid bilayer-coated piezoelectric crystals." Journal of the Chemical Society, Chemical Communications, no. 18 (1987): 1363. http://dx.doi.org/10.1039/c39870001363.

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Guinard, J. "Does consumption of beer, alcohol, and bitter substances affect bitterness perception?" Physiology & Behavior 59, no. 4-5 (May 1996): 625–31. http://dx.doi.org/10.1016/0031-9384(95)02124-8.

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Geran, Laura C., and Susan P. Travers. "Single Neurons in the Nucleus of the Solitary Tract Respond Selectively to Bitter Taste Stimuli." Journal of Neurophysiology 96, no. 5 (November 2006): 2513–27. http://dx.doi.org/10.1152/jn.00607.2006.

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Molecular data suggest that receptors for all bitter ligands are coexpressed in the same taste receptor cells (TRCs), whereas physiological results indicate that individual TRCs respond to only a subset of bitter stimuli. It is also unclear to what extent bitter-responsive neurons are stimulated by nonbitter stimuli. To explore these issues, single neuron responses were recorded from the rat nucleus of the solitary tract (NST) during whole mouth stimulation with a variety of bitter compounds: 10 μM cycloheximide, 7 mM propylthiouracil, 10 mM denatonium benzoate, and 3 mM quinine hydrochloride at intensities matched for behavioral effectiveness. Stimuli representing the remaining putative taste qualities were also tested. Particular emphasis was given to activating taste receptors in the foliate papillae innervated by the quinine-sensitive glossopharyngeal nerve. This method revealed a novel population of bitter-best (B-best) cells with foliate receptive fields and significant selectivity for bitter tastants. Across all neurons, multidimensional scaling depicted bitter stimuli as loosely clustered yet clearly distinct from nonbitter tastants. When neurons with posterior receptive fields were analyzed alone, bitter stimuli formed a tighter cluster. Nevertheless, responses to bitter stimuli were variable across B-best neurons, with cycloheximide the most, and quinine the least frequent optimal stimulus. These results indicate heterogeneity for the processing of ionic and nonionic bitter tastants, which is dependent on receptive field. Further, they suggest that neurons selective for bitter substances could contribute to taste coding.

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IIYAMA, Satoru, Kiyoshi TOKO, and Kaoru YAMAFUJI. "Effect of bitter substances on a model membrane system of taste reception." Agricultural and Biological Chemistry 50, no. 11 (1986): 2709–14. http://dx.doi.org/10.1271/bbb1961.50.2709.

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KUBÍČEK, J. "Higher yields of bitter substances from hop using kieselguhr during hop boiling." Kvasny Prumysl 33, no. 8 (August 1, 1987): 254–59. http://dx.doi.org/10.18832/kp1987051.

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ŠROGL, J., J. ČEPIČKA, and P. PRŮCHA. "The changes of bitter substances contents during fermentation in cylindro-conical vessels." Kvasny Prumysl 40, no. 10 (October 1, 1994): 296–300. http://dx.doi.org/10.18832/kp1994019.

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Journal articles on the topic 'Chemistry of bitter substances'

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