1-1-diphenyl-2-picrylhydrazyl and procyanidin

In this work, an efficient method for preparative separation of procyanidins from raw cacao bean extract by high-speed counter-current chromatography (HSCCC) was developed. Under the optimized solvent system of n-hexane-ethyl acetate-water (1:50:50, v/v/v) with a combination of head-tail and tail-head elution modes, various procyanidins fractions with different polymerization degrees were successfully separated. UPLC, QTOF-MS and

Topics: Antioxidants; Benzothiazoles; Biflavonoids; Biphenyl Compounds; Cacao; Catechin; Chromatography, High Pressure Liquid; Countercurrent Distribution; Picrates; Plant Extracts; Proanthocyanidins; Solvents; Sulfonic Acids

In this study, a crude polyphenol extract (CPE) from defatted grape seeds was evaluated for antioxidant and cytoprotective effects in PC12 cells. The CPE was then fractionated into a catechin and oligomeric procyanidin fraction (F(cat+olig)) and a polymeric procyanidin fraction (F(pol)), and the bioactivities of the fractions were evaluated individually. F(pol) was the richest in total polyphenol, total flavonoid, and polymeric procyanidin but contained less flavan-3-ol than F(cat+olig). Consistent with these results, F(pol) had the highest 2,2-diphenyl-β-picrylhydrazyl radical scavenging activity and reducing power. Both F(cat+olig) and F(pol) had higher 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic) acid radical scavenging activity than CPE. The resistance of PC12 cells against oxidative stress, after pretreatment with F(pol) (200 μg/mL) for 9 h, was 100.7±2.9% of that in the control. Moreover, pretreating these cells with F(cat+olig) and F(pol) significantly decreased reactive oxygen species generation. These results provide information on a potential new source of antioxidants in the form of a functional food derived from an agricultural by-product.

Topics: Animals; Antioxidants; Biflavonoids; Biphenyl Compounds; Catechin; Oxidative Stress; PC12 Cells; Picrates; Plant Extracts; Polyphenols; Proanthocyanidins; Rats; Reactive Oxygen Species; Seeds; Vitis

Eight antioxidants from five different polyphenolic classes (cinnamic acids, benzoic acids, flavonoids, proanthocyanidins and stilbenes), and the water-soluble vitamin E derivative trolox were examined for their antioxidant activity in-vitro. In addition, the compounds were tested for their cytotoxicity on growing fibroblasts and their inhibition of the classical pathway of the complement system. Procyanidin C1 was shown to be a good scavenger of both DPPH(*) and HO(*), and a strong inhibitor of lipid peroxidation and the classical pathway of the complement system. Consequently, procyanidin C1 was classified as the most promising antioxidant in-vitro of all compounds tested. In contrast, genistein exhibited a very low antioxidant activity in both the lipid peroxidation and the DPPH(*) scavenging assay, a high cytotoxicity and a low complement-inhibiting activity.

Topics: Antioxidants; Benzoates; Biflavonoids; Biphenyl Compounds; Catechin; Cell Survival; Cells, Cultured; Chromans; Cinnamates; Dose-Response Relationship, Drug; Fibroblasts; Flavonoids; Free Radicals; Genistein; Humans; Hydrazines; Hydroxyl Radical; Lipid Peroxidation; Phenols; Picrates; Polyphenols; Proanthocyanidins; Skin; Stilbenes

The extracts from white-, black-, and red-hulled rice were prepared by sequential extraction with six different polar solvents, and their radical-scavenging activities were measured by methods using 1,1-diphenyl-2-picrylhydrazyl radical (DPPH*) and tert-butyl hydroperoxyl radical (t-BuOO*). The extracts prepared with highly polar solvents, methanol and deionized water, exhibited higher DPPH* and t-BuOO* scavenging activities in all three cultivars. In addition, the acetone extract from red-hulled rice exhibited a high DPPH* and t-BuOO* scavenging activity, while no such activity was detected for the acetone extracts from white- and black-hulled rice. The major components responsible for the radical scavenging in the acetone extract from red-hulled rice were identified as procyanidins by acidic hydrolysis, vanillin assay, and Sephadex LH-20 chromatography. GPC analysis of the acetylated procyanidins revealed that the average molecular weight is about 5000, in a range of about 500-18,000.

Topics: Antioxidants; Biflavonoids; Biphenyl Compounds; Catechin; Chemical Fractionation; Chromatography, High Pressure Liquid; Color; Food Handling; Free Radical Scavengers; Hydrogen-Ion Concentration; Hydrolysis; Luminescent Measurements; Oryza; Picrates; Plant Extracts; Proanthocyanidins; Seeds; tert-Butylhydroperoxide

New bio-based antioxidant compounds have been obtained by depolymerisation of grape polymeric flavanols in the presence of cysteine. Their preparation and purification, as well as their antiradical/antioxidant and antiproliferative properties are reported. 4beta-(S-cysteinyl)epicatechin 5, 4beta-(S-cysteinyl)catechin 6 and 4beta-(S-cysteinyl)epicatechin 3-O-gallate 7 were efficiently purified from the crude depolymerised mixture by cation-exchange chromatography and preparative reversed-phase chromatography. The new compounds were more efficient than the underivatised (-)-epicatechin 1 as scavengers of the 1,1-diphenyl-2-picrylhydrazyl free radical (DPPH) and weak growth inhibitors of human colon carcinoma HT29 cells. The order of antiradical and antiproliferative efficiency was 7 >5 approximately 6 >1, the same for both assays.

Topics: Antineoplastic Agents; Antioxidants; Biflavonoids; Biphenyl Compounds; Catechin; Cell Division; Cysteine; Flavonoids; Free Radical Scavengers; Humans; Picrates; Proanthocyanidins; Structure-Activity Relationship; Tumor Cells, Cultured; Vitis

The effect of procyanidin solutions on superoxide anion radicals was studied with an enzymatic method and their EC(50) values were determined. A comparative study of the results suggested that the free radical scavenger potential of these phenolic compounds closely depends on their chemical and stereochemical structures. Oligomeric procyanidins were isolated in different fractions from grapes and wines by low- and high-pressure liquid chromatography. These compounds were found to be efficient free radical scavengers even for the weak concentrations in wines. Their activity in grapes or wines was much stronger than that of other commercially available natural antioxidants (such as ascorbic acid and gallic acid). The effect of tannins isolated from grapes on different radicals was analyzed according to three distinct methods: an enzymatic method for superoxide anion radicals (O(2)(*)(-)), a chemical method for the stable 1,1-diphenyl-2-picrylhydrazyl radical (DPPH(*)), and an immunochemical method to study the scavenging activity of seed procyanidins on DNA lesions induced by the radical HO(*).

Topics: Bepridil; Biflavonoids; Biphenyl Compounds; Catechin; DNA; Flavonoids; Free Radical Scavengers; Indicators and Reagents; Phenols; Picrates; Polymers; Proanthocyanidins; Rosales; Superoxides; Tannins; Wine; Xanthine Oxidase