Antioxidant potentials of five flavonoids compounds isolated from Varthemia iphionoids

Abstract

Purpose: To evaluate the in vitro antioxidant activity of some flavonoids isolated from Varthemia iphionoids aqueous methanol extract. Methods: A portion (330 g) of the aqueous methanol extract of Varthemia iphionoids was adsorbed onto 200 g of S silica gel (70 - 230 mesh) and then loaded onto a column of S silica gel (70 - 230 mesh, 100 g). The column was packed with chloroform and eluted with chloroform-methanol mixtures of increasing polarity. Column chromatography purification (silica gel, 400 mesh) and thin-layer chromatography (TLC) or recrystallization yielded 5 compounds subsequently identified by nuclear magnetic resonance (NMR) and mass spectroscopy (MS). Results: The antioxidant activities of five identified flavonoids: Kumatakillin (1), Penduletin (2), Jeceidine (3), 6-Methoxy isokaemfride (4), and 3,3'-Di-O-methyl quercetin (5) were determined. The results indicated that compound 3 exhibited the best scavenging activity against DPPH radical and H2O2 comparable to that of quercetin as standard. All compounds had the ability to prevent the oxidation of β- carotene. In anti-hemolytic assay, the five compounds gave HT50 higher than vitamin C. The best protection activity of erythrocytes membrane was recorded with compound 2 (HT50 = 60.14 ± 0.72 min). Moreover, all compounds had significantly increased blood clotting time, and among them, compounds 1, 2, and 3 exhibited significantly increased thrombolytic activity compared to the control (***p < 0.001). Conclusion: These results indicate that Varthemia iphionoids has good antioxidant activities but further studies on the plant extract are required.