Isolation of flavonoids, a biscoumarin and an amide from the flower buds of Daphne genkwa and the evaluation of their anti‐complement activity

Abstract As part of an ongoing study aimed at identifying the anti‐complement active compound from the flower buds of Daphne genkwa , ten flavonoids, one biscoumarin and one amide were isolated. Their structures were identified from spectroscopic and physicochemical data as genkwanin 5‐ O‐β ‐ d ‐primveroside (1), apigenin 7‐ O‐β ‐ d ‐glucuronide (2), genkwanin 5‐ O‐β ‐ d ‐glucopyranoside (3), apigenin 5‐ O‐β ‐ d ‐glucopyranoside (4), genkwanin (5), apigenin (6), luteolin 7‐methyl ether (7), luteolin (8), daphnoretin (9), velutin (10), 7‐methoxyacacetin (11) and aurantiamide acetate (12). Among them, compounds 9, 10 and 12 were isolated from this plant for the first time. The anti‐complement activity of these compounds was tested against the classical pathway of the complement system. Among the compounds, daphnoretin (9) exhibited significant anti‐complement activity with an IC 50 value of 11.4 µ m , whereas the other compounds were not active in the assay. Copyright © 2006 John Wiley & Sons, Ltd.