Shamimin: a new flavonol C-glycoside from leaves of Bombax ceiba.

Shamimin a new flavonol C-glycoside has been isolated as a pale yellow powder from the ethanolic extract of fresh, undried leaves of Bombax ceiba. Its structure has been elucidated as 2-(2,4,5-trihydroxyphenyl)-3,5,7-trihydroxy-6-C- glucopyranosyloxy-4H-1-benzopyran-4-one through extensive spectroscopic methods (IR, mass, 1H- and 13C-NMR), and 2D-NMR experiments. Shamimin showed antimicrobial activity against a few bacteria and fungi.