Isolation and structural identification of C-glycosylflavones from Corallodiscus flabellata

AimTo study the chemical constituents of Corallodiscus flabellata. MethodsFresh plant of Corallodiscus flabellata was extracted twice with boiling water, concentrated to small volume under reduced pressure at 55 ℃. The concentrated material was partitioned with ether, ethyl acetate, and n-butanol. The fraction of ethyl acetate extract was chromatographed over macroporous adsorption resin (Diaion HP-20) eluted with a mixture of H₂O and MeOH in increasing MeOH content. Their fractions from resin were repeatedly chromatographed over Sephadex LH-20, silica gel column chromatography. The compounds were identified on the basis of their physiochemical and spectral data. ResultsSeven compounds were obtained and identified as 5,3′,4′-trihydroxyl-6,7-dimethoxyl-8-C-［β-D-xylocopyranosyl-(1→2)］-β-D-glucopyranosyl flavone (1), 5,4′-dihydroxyl-6,7-dimethoxyl-8-C-［β-D-xylopyranosyl-(1→2)］-β-D-glucopyranosyl flavone (2), 5,4′-dihydroxyl-6,7-dimethoxyl-8-C-β-D-glucopyranosyl flavone (3), 5,4′-dihydroxyl-6,7-dimethoxyl-8-C-［β-D-apiofuranosyl-(1→2)］-β-D-glucopyranosyl flavone (4), 3,4-dihydroxyl benzoyl acetic acid glycol ester (5), hydroxytyrosol (6), apocynin (7). ConclusionCompound 1 and 2 are new compounds, the others were isolated from Corallodiscus flabellata for the first time.