Peroxidation inhibition DPPH radicals

Japanese scientists believe that the anti-oketsu effects of rhubarb are brought about by the inhibition of the production of nitric oxide, inhibition of platelet aggregation, antiallergic effects, and its antiinflammatory properties. Matsuda et al. (2001) studied and reported that the methanolic extracts from five kinds of rhubarb were found to show scavenging activity for l,l-diphenyl-2-picrylhy-drazyl (DPPH) radical and superoxide anion radical (02 ) generated by the xanthine/xanthine oxidase system and/or on lipid peroxidation by terf-butyl hydroperoxide (f-BuOOH) in the erythrocyte membrane ghost system. 

Fungus Epicoccum sp. was isolated from the marine brown alga Fucus vesiculosus. From the cultivated fungus, a new secondary metabolite 4,5,6-trihydroxy-7-methylphthalide 336 (epicoccone) was found. 336 was found to be potently active, showing 95% DPPH radical scavenging effects at 25 pg mL. It also inhibited the peroxidation of linolenic acid in the TEARS assay (62 % inhibition at 37 pg mL ). 

Compounds Super oxide scavenging actmty[lC >(uM)l Lipid peroxide inhibition activityriCsn(uM)l DPPH radical [SC, (pM)]... 

IC50 is the concentration required for 50% inhibition of lipid peroxidation or scavenging of DPPH radical. TEAC is the trolox equivalent antioxidant capacity, which is defined as the mM concentration of a trolox solution having the antioxidant capacity equivalent to a 1.0 mM solution of the substance under investigation. 

In our own study on H. diffusa using chemical-based assays such as the ferric thiocyanate (FTC), thiobarbituric acid (TBA), and diphenylpicrylhydrazyl (DPPH) radical-scavenging methods [31], we found that both quercetin 3-0-/ -glucopyranoside (21) and quercetin 3-O- -rutinoside (22) inhibited linoleic acid peroxidation and also exhibited good DPPH radical-scavenging properties (87-88%) which was comparable to vitamin C (93%). We also found asperuloside to be inactive in both assays. 

SPs not only function as dietary fiber, but they also contribute to the antioxidant activity of marine algae. It has been demonstrated that SPs have potential antioxidant activity and various classes of SPs including fucoidan, laminaran, and alginic acid have been shown as potent antioxidants (Rocha de Souza et ah, 2007 Ruperez et ah, 2002 Wang et ah, 2008). Antioxidant activity of SPs have been determined by various methods such as l,l-diphenyl-2-picryl hydrazil (DPPH) radical scavenging, lipid peroxidation inhibition, ferric reducing antioxidant power (FRAP), nitric... 

Allspice oleoresin gave a positive result in the DNA-repair test but not in the Ames Salmonella reversion assay or the Bacillus subtilis rec assay (Sekizawa and Shibamoto 1982). Antimutagenicity via antioxidant activity of allspice was observed in the DPPH radical reduction assay and lipid peroxidation inhibition testing (Ramos et al. 2003). 

Rat liver mitochondria Inhibition of lipid peroxidation induced by ADP/Fe and scavenging of DPPH radicals by capsaicin [127]... 

ETWl and ETW2 (mannans) Edwardsiella tarda scavenging capacities on DPPH and hydroxyl radicals, and lipid peroxidation inhibition in-vitro [110]... 

Atalay et al. (2011) determined the lipid peroxidation inhibition potential for nine lichen compounds in two lipid peroxidation test systems (liposome and emulsion systems). They found that isidiophorin, rhizonaldehyde, rhizonyl alcohol and pulmonarianin retarded lipid peroxidation at in both test systems. However, stictic acid and ergosterol peroxide exhibited antioxidant activity in only the liposome test system. Usnic acid and diffractaic acid were not antioxidants in either system, while stictic acid was not lipid peroxidation inhibitor in the emulsion test system. All compounds, which inhibited lipid peroxidation in both test systems, were also DPPH radical scavengers. 

Alcoholic extracts of the roots and leaves of E. angustifolia, E. pallida, and E. purpurea exhibited comparable in vitro antioxidant activities in ABTS free radical scavenging assay, and the root extracts were also active in the lipid peroxidation inhibition assay.Methanolic extracts of freeze-dried roots of the three species act as in vitro antioxidants through the scavenging of DPPH and ABTS radicals, as well as by chelation of the copper ion (Cu Copper-catalyzed oxidation of human LDL was further demonstrated in vitro by different preparations from E. purpurea root containing alkamides, caffeoyl derivatives, and polysaccharides, as well as by pure caffeoyl derivatives. The antioxidant effect was synergistic and dose dependent. ... 

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