Antioxidant activities of flavidin in different in vitro model systems.

Flavidin was isolated from Orchidaceae species and purified by silica gel column chromatography. The structure was identified using physical and spectral ((1)H, (13)C NMR, and mass) data. Antioxidant potency of flavidin was investigated employing various established in vitro model systems viz., beta-carotene-linoleate, 1,1-diphenyl-2-picryl hydrazyl (DPPH), phosphomolybdenum method, and scavenging of hydrogen peroxide methods. Flavidin showed very good antioxidant activity (90.2%) and almost equivalent to that of BHA at 50ppm level by beta-carotene-linoleate method. Radical scavenging activity of flavidin was compared with BHA at 5, 10, 20, and 40ppm concentration and flavidin showed more radical scavenging activity than BHA at all the tested concentrations. Furthermore, flavidin showed very good antioxidant capacity by the formation of phosphomolybdenum complex method. Besides this, flavidin showed effective hydrogen peroxide scavenging activity. The data obtained in the in vitro models clearly establish the antioxidant potency of flavidin. However, comprehensive studies need to be conducted to ascertain the in vivo safety of flavidin in experimental animal models. This is the first report on antioxidant activity of 9,10-dihydro-5H-phenanthro-(4,5 bcd)-pyrans/flavidin type of compounds.