Добірка наукової літератури з теми "TLC-DPPH"

AbstractThere is limited literature on the antioxidative properties of food of animal origin. Measurements of antioxidative properties are usually performed using the reaction of reduction of colored 2,2-diphenyl-1-picrylhydrazyl (DPPH) radials. Changes of the DPPH color are tracked photometrically. These measurements are interfered by both, the tested samples and reduced DPPH. This study aims to demonstrate the ability to separate different forms of DPPH (DPPH• and DPPH-H) by thin-layer chromatography (TLC). Further, it has been practically applied in the study of the determination of antioxidative properties of the meat samples. It was found that TLC can be used for the separation of different forms of DPPH as well as for measurement of TAP (total antioxidant potential) values related to the DPPH•. The strongest antioxidant properties were observed for pork neck extracted in buffer pH 2 and for smoked salmon fish extracted in acetone, the lowest for veal and turkey fillet extracted in methanol.

Introdução: As substâncias antioxidantes ocupam um lugar de destaque dentro das diferentes áreas da indústria, sendo importante a realização de pesquisa sistematizada desses compostos e de suas capacidades de neutralizar agentes nocivos, como por exemplo, os radicais livres. A espécie Morinda citrifolia, conhecida por noni, possui uma longa história de uso como remédio popular. Objetivo: buscar substâncias com capacidade antioxidante em diferentes extratos de M. citrifolia. Metodologia: A semente, raiz, caule e folha foram seca em estufa de ar circulante e trituradas em moinho de facas do tipo Willy, com exceção da polpa. Os extratos foram obtidos através de extração sequencial com solventes de polaridade crescente (hexano, acetato de etila e metanol) por maceração em mariotte. As análises da capacidade antioxidante foram realizadas pela técnica TLC-DPPH• em duas etapas. A primeira etapa realizou-se varredura para determinar quais dos extratos obtidos possuem capacidade antioxidante por TLC-DPPH•. A segunda etapa avaliou-se os extratos ativos, e através do perfil cromatográfico identificou o Rf com atividade antioxidante. Resultados: A avaliação antioxidante por TLC-DPPH• na primeira etapa observou-se que somente o spot do extrato em acetato de etila da semente demonstrou melhor atividade antioxidante quando comparando aos padrões utilizados. Na segunda etapa somente o Rf=0,7 do extrato em acetato de etila apresentaram a atividade antioxidante, comparado com os padrões. Conclusão: O método TLC-DPPH• demonstrou ser um procedimento rápido e preciso na separação de diferentes extratos e na identificação de compostos ativos, sendo que abordagem mostrou perspectivas de isolamento de substâncias com propriedades antioxidantes.

The free radical is an unstable molecule because contains one or two unpaired electrons. The antioxidant substance is a simple way to decrease the illness caused by free radicals. Cawat hanoman (Bauhinia aculeata L.) was known to contain tannin components one of the benefits as an antioxidant. This research aims to determine the antioxidant activity of the B. aculeata stem tested by qualitatively used thin-layer chromatography (TLC) and quantitatively using the DPPH method. Bauhinia aculeata stem was extracted using a maceration extract method with 96% ethanol. Antioxidant activity test was done qualitatively by eluent of ethyl acetate : methanol : purified water (6 : 2 : 1) using TLC and quantitatively using the DPPH method. The result of antioxidant activity from 96% ethanol extract of B. aculeata stem qualitatively showed the presence of yellow spots on a purple background at TLC after syringed DPPH 0.5 mM and quantitative test that resulted in an IC50 of 21.862 �g/mL. These results indicate that 96% ethanol extract of B. aculeata has very strong antioxidant activity.

Seaweeds are important sources of carotenoids, and numerous studies have shown the beneficial effects of these pigments on human health. In the present study,Himanthalia elongatabrown seaweed was extracted with a mixture of low polarity solvents, and the crude extract was separated using analytical thin-layer chromatography (TLC). The separated compounds were tested for their potential antioxidant capacity and antimicrobial activity againstListeria monocytogenesbacteria using TLC bioautography approach. For bio-autography, the coloured band on TLC chromatogram was visualized after spraying with DPPH and triphenyl-tetrazolium chloride reagents which screen antioxidant and antimicrobial compounds, respectively, and only one active compound was screened on the TLC plate. Preliminary identification of this active compound was done by comparing its colour andRf(retention factor) value with the authentic fucoxanthin standard. Further, the active compound was purified using preparative TLC. This purified compound showed a strong antioxidant (EC50:14.8±1.27 µg/mL) and antimicrobial (inhibition zone: 10.27 mm, 25 µg compound/disc) activities, which were examined by DPPH scavenging and agar disc-diffusion bioassay, respectively. The bioactivity shown by the purified compound was almost similar to the fucoxanthin standard. The characteristic UV-visible and FT-IR spectra of the purified active compound completely matched with the standard. Hence, the main active compound inH. elongatawas identified as fucoxanthin.

Phytochemical profile is an important aspect as it will give an over view of possible pharmacological properties of the plant. Justicia neesii is a plant belongs to Acanthaceae family, on which no significant phytochemical and pharmacological was done. The objective of the present study is to elucidate the phytochemical profile and analysis of antioxidant properties by TLC method. The phytochemical analysis was done for screening the maximum number of phytochemicals using standard methods. The TLC plates were developed with a solvent system containing methanol: chloroform: hexane at a ratio of 7:2:1. Ascorbic acid was used as positive control and a blank TLC plate was used as negative control in the experiment. The diluted DPPH in methanol was sprayed on the developed plates and observed under UV light. The preliminary phytochemical analysis shows the presence of flavonoids, glycosides, lactones, lignins, phenols, phytosterols, quinins, reducing sugars, saponins and terpinoids. The TLC analysis has shown the higher intensity of yellow color for the test spots which indicating the higher antioxidant potential of plant extract compared to standard ascorbic acid after treatment with DPPH solution. The plant is having good antioxidant potential. The plant was also composed of many significant phytochemicals.

Abstract This paper reviews a selection of the most important studies on antioxidants in foods (including beverages), food ingredients, and dietary supplements by effect-directed analysis using TLC with DPPH*, ABTS*+, and β-carotene direct bioautography. Total antioxidant activity by visible mode spectrometry (colorimetry) with TLC used offline to obtain additional analytical results, mostly for identification and quantification of phenolic compounds in samples, is also discussed. Finally, dot-blot assay for total antioxidant activity, carried out on a TLC plate without mobile-phase development, is reviewed as an alternative with possible advantages compared with spectrometry.

In order to screen natural antioxidant, the research about antioxidant of some Euphobiaceae herbs, have been conducted. The air-dried herbs of Euphorbia heterophylla L, Phyllanthus acidus (L.) Skeels, and Phyllanthus buxifolius Muell Arg were extracted with metanol. The obtained extract was concentrated and then suspended to produce n-hexane, ethyl acetat and aqueous fractions. Free radical scavenger activity against DPPH (1,1-diphenyl-2-pycrylhydrazyl) measured by spectrophotometric method and the IC50 value was determined. The compounds of active fraction had been identified by TLC method. All of the herbs showed activity as DPPH scavenger. Among these herbs, Euphorbia heterophylla L. and Phyllanthus buxifolius Muell, Arg. exhibited a strong free radical scavenging of ethyl acetat fraction with IC50 value 5,88 µg/ml and 4,64 µg/ml. The result of TLC by mobile phase n-buthanol-acetic acid-water (4:1:5) and acetic acid 15% showed flavonoid compound.Keywords: Euphorbiaceae herbs, antioxidant, DPPH, flavonoid

Abstract Background: Interest in the antioxidant and antidiabetic activity of natural products are growing vastly in the modern world. Thin layer chromatography-bioautography-mass spectroscopy (TLC-bioautography-MS) plays an important role in chemico-biological screening of natural sources. TLC combined with 2, 2-Diphenyl-1-picrylhydrazyl (DPPH) free radical, α-amylase and α-glucosidase bioassay were used to evaluate antioxidant and antidiabetic activities, respectively, in different extracts of Citrullus colocynthis (Hanzal), a well-known traditional Indian Unani medicinal plant. Objective: To develop a TLC-bioautographic-MS method for DPPH, α-amylase, and glucosidase inhibitors in different extract of C. colocynthis fruits. Method: Fruits of C. colocynthis were successively extracted with toluene, dichloromethane, ethyl acetate, methanol, and water. TLC solvents were developed, and bioautographic-MS analysis was carried out to identify the antioxidant and antidiabetic compounds. Results: HPTLC fingerprinting analysis showed maximum numbers of band separated in dichloromethane and ethyl acetate extracts of C. colocynthis, fourteen and thirteen at 254 and 366 nm, respectively. Whereas six and five separated bands were observed in toluene extract at 254 and 366 nm, respectively showed minimum numbers of metabolites. Based on TLC-bioautography-MS, maximum number of antioxidant compounds were identified in dichloromethane extract. Except aqueous extract of C. colocynthis, all the extracts have shown antidiabetic activity. On the other hand, there were no antioxidant compounds in methanolic extract of C. colocynthis. Conclusions: The results of this study reveal that TLC-bioautography-MS–guided strategy used to identify antioxidant and antidiabetic compounds of C. colocynthis is very useful technique for high-throughput screening of bioactive compounds. Highlights: TLC-MS bioautography is a simple and fast to enables bioactive compounds present in extracts.

La recherche de nouveaux composés pour prévenir ou atténuer le vieillissement de la peau est une priorité des recherches actuelles dans les cosmétiques. Dans ce contexte, le venin de frelon asiatique (Vespa velutina nigrithorax) a été étudié comme une source particulière de molécules potentiellement bioactives d’intérêt dermacosmétique. La première étude a tout d’abord porté sur la mise en œuvre d’un protocole fiable d’extraction et récupération du venin. Puis, la fraction peptidique et petites molécules a été sélectionnée afin d’évaluer, en comparaison avec le venin brut, la présence de molécules actives vis-à-vis d’une activité antioxydante, anti-microbienne (C. acnes) et inhibitrice enzymatique (tyrosinase, élastase, collagénase) in-tubo et in-cellulo. Ces études ont conduit à identifier par UHPLC-ESI-QTOF-HRMS/MS, dans le venin brut, une molécule responsable de l’activité anti-oxydante sur kératinocytes HaCaT. Dans une seconde étude, une approche peptidomique basée sur une méthode UHPLC-QTOF-HRMS et MS/MS suivie par un traitement statistique (PCA, PLS-DA) a été appliquée sur l’étude différentielle de profil peptidique du venin, en fonction de la période de collecte, des castes et du comportement. Ces derniers ont pour but d’évaluer l’influence de différents facteurs sur le patrimoine moléculaire de ces venins. Parallèlement, en troisième étude, une approche de criblage d’interaction Ligand/enzyme par spectrométrie de masse sur les enzymes élastase et tyrosinase immobilisées a été développée. Cette méthode a pour objectif de mettre en évidence la présence d’inhibiteurs ou de substrats dans des fractions plus ou moins complexes. On a montré que deux peptides présents dans le venin de frelon étaient capables d’interagir avec l’enzyme élastase en tant que substrat. La séquence peptidique de ces peptides a été partiellement obtenue par séquençage de novo
The search for new compounds to prevent or attenuate skin aging is a priority in current research in cosmetics. In this context, Asian Hornet venom (Vespa velutina nigrithorax) has been studied as a particular source of potentially bioactive molecules for dermacosmetic interest.The first study focused on the implementation of a reliable venom extraction and sampling protocol. Then, the peptide - small molecules fraction was selected to evaluate, in comparison with crude venom, the presence of active molecules with respect to antioxidant, anti-microbial (C. acnes) and enzyme inhibition (tyrosinase, elastase, collagenase) activity in-tubo and in-cellulo. These studies led to the identification in crude venom, by UHPLC-ESI-QTOF-HRMS/MS, of one molecule responsible for antioxidant activity on HaCaT keratinocytes.In a second study, a peptidomic approach based on UHPLC-ESI-QTOF-HRMS/MS followed by statistical processing (PCA, PLS-DA) was applied to the differential study of venom, according to the collection period, castes and behavior. The latter aims at evaluating the influence of these different factors on the venom molecular heritage. At the same time, in a third study, a ligand/enzyme interaction screening approach by mass spectrometry on solid-supported elastase enzymes was developed. The aim of this method is to detect the presence of inhibitors or substrates in more or less complex fractions. Two hornet venom peptides presenting in the hornet venom were identified to be capable of interacting with the enzyme elastase. Their peptide sequences were then partially obtained by de novo sequencing