Herpetolide C: one new 7H-dibenzoc,eoxepin-5-one from Herpetospermum caudigerum

The chemical constituents of Herpetospermum caudigerum were investigated using chromatographic methods, including silica gel column chromatography, Sephadex LH-20 and semi-preparative HPLC. Four compounds were isolated and their structures were elucidated by spectral data and physicochemical properties, which were identified as 2,11-dimethoxy-3,9-dihydroxy-7H-dibenzoc,eoxepin-5-one (1), 7,8'-didehydroherpetotriol (2), herpetotriol (3) and kaempferitrin (4). Among those, compound 1 is one new 7H-dibenzoc,e oxepin-5-one, named as herpetolide C.