Comparative Study of the Antioxidant, Free Radical Scavenging Activity and Human LDL Oxidation Inhibition of Three Extracts From Seeds of a Cameroonian Spice, Xylopia parviflora (A. Rich.) Benth. (Annonaceae)

摘要

The antioxidant activity of water, ethanol and hydroethanolic extracts of the spice Xylopia parviflora (A. Rich.) Benth. (Annonaceae) from Cameroon, was evaluated using different antioxidant tests such as O~(-2), OHcentre dot, NO, DPPH, ABTSdcentre dot~+ scavenging activities, FRAP, as well as metal chelation and inhibition of copper-induced in vitro human low density lipoprotein (LDL) and a-linoleic acid oxidation. DPPH and ABTS were determined kinetically. Compared with two other extracts, the water extract exhibited the lowest phenolic content, AE_(ABTS) and AE_(DPPH) values while the ethanol extract had the highest phenolic content and reductive potential and the hydroethanolic extract the highest AE_(ABTS) and AE_(DPPH)values (P < 0.05). All extracts exhibited a dose dependent inhibition of O~(-2), OHcentre dot, NO, radicals, metal chelating activity and inhibition of a-linoleic acid and LDL oxidation (P < 0.05). Those various antioxidant activities were compared to standard antioxidants such as catechin and ascorbic acid. Compared with controls, each extract significantly decreased malondialdehyde and lipid hydroperoxide formation in LDL (P < 0.05). Contrary to other antioxidant methods where the ethanolic extract was the most potent, the hydroethanolic extract exhibited the highest inhibition of LDL oxidation, metal chelating and nitric oxide scavenging activities. Therefore, Xylopia parviflora could be a good source of natural antioxidant.