Two New Flavones from Tridax procumbens Linn

Two new flavones, 8,3′-dihydroxy-3,7,4′-trimethoxy-6-O-β-D-glucopyranosyl flavone (1) and 6,8,3′-trihydroxy-3,7,4′-trimethoxyflavone (2) were isolated from Tridax procumbens Linn., together with the four known compounds puerarin (3), esculetin (4), oleanolic acid (5) and betulinic acid (6). The structures of the two new flavones were elucidated based on chemical analysis and spectral methods (IR, 1D and 2D NMR, ESI-MS, HR-ESI-MS). The antioxidant activity of the two new flavones were evaluated by two methods, the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and ferric reducing antioxidant power (FRAP) assays, and the data showed that compounds 1 and 2 have certain antioxidant activity, with the antioxidant activity of compound 2 being stronger than that of compound 1.