Antioxidant properties of a North American ginseng extract.
A North American ginseng extract (NAGE) containing known principle ginsenosides for Panax quinquefolius was assayed for metal chelation, affinity to scavenge DPPH-stable free radical, and peroxyl (LOO*) and hydroxyl (*OH) free radicals for the purpose of characterizing mechanisms of antioxidant activity. Dissociation constants (Kd) for NAGE to bind transition metals were in the order of Fe2+ > Cu2+ > Fe3+ and corresponded to the affinity to inhibit metal induced lipid peroxidation. In a metal-free linoleic acid emulsion, NAGE exhibited a significant (p < or = 0.05) concentration (0.01-10 mg/mL) dependent mitigation of lipid oxidation as assessed by the ammonium thiocyanate method. Similar results were obtained when NAGE was incubated in a methyl linoleate emulsion containing haemoglobin catalyst and assessed by an oxygen electrode. NAGE also showed strong DPPH radical scavenging activity up to a concentration of 1.6 mg/mL (r2 = 0.996). Similar results were obtained for scavenging of both site-specific and non site-specific *OH, using the deoxyribose assay method. Moreover, NAGE effectively inhibited the non site-specific DNA strand breakage caused by Fenton agents, and suppressed the Fenton induced oxidation of a 66 Kd soluble protein obtained from mouse brain over a concentration range of 2-40 mg/mL. These results indicate that NAGE exhibits effective antioxidant activity in both lipid and aqueous mediums by both chelation of metal ions and scavenging of free radicals.
Kitts
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Food, Nutrition and Health, Faculty of Agricultural Sciences, University of British Columbia, Vancouver, Canada.
Wijewickreme
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AN
Hu
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D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001921:Brain / Q000187:drug effects / Q000378:metabolism; D002384:Catalysis; D016166:Free Radical Scavengers / Q000494:pharmacology; D006454:Hemoglobins / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D008670:Metals / Q000378:metabolism; D051379:Mice; D005894:Panax / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal; D051381:Rats; D013861:Thiocyanates / Q000378:metabolism
D000975:Antioxidants; D016166:Free Radical Scavengers; D006454:Hemoglobins; D008670:Metals; D010936:Plant Extracts; D013861:Thiocyanates; C026976:thiocyanic acid