Uncinataflavone, a new flavonoid with a methyl benzoate substituent from Selaginella uncinata

Uncinataflavone (1), a new flavonoid, together with four known compounds (2-5), was isolated from Selaginella uncinata (Desv.) Spring. Compounds 2 and 3 were isolated from the genus selaginella for the first time. The structure of the new compound was determined as methyl 3-(5,7-dihydroxy-2-(4-hydroxyphenyl)-4-oxo-4H-chromen-6-yl)-4-methoxybenzoate by means of spectroscopic evidence, including UV, IR, 1D and 2D NMR analyses as well as HR-ESI-MS. These compounds (1-5) were evaluated for the antioxidant activity in 1,1-diphenyl-2-picrylhydrazyl assay system.