Novel caffeoylquinic acid derivatives from Lonicera japonica Thunb. flower buds exert pronounced anti-HBV activities.

Lonicera japonica Thunb., possesses antiviral and hepatoprotective activities, and is widely used as a health food and in cosmetics. However, its major constituents, caffeoylquinic acid derivatives, and their anti-HBV activity were lacking systematic research. In this study, four novel caffeoylquinic acids, five simple caffeic acids and fourteen known caffeoylquinic acids are isolated and identified from L. japonica . Most caffeoylquinic acids inhibited HBsAg and HBeAg secretion, and HBV DNA replication. In particular, 100 μg ml -1 monocaffeoylquinic acid 9 inhibits HBsAg and HBeAg secretion, and HBV DNA replication by 83.82, 70.76 and 39.36% compared to the control. Unfortunately, 50 μg ml -1 tricaffeoylquinic acid 23 promotes HBsAg and HBeAg secretion, and HBV DNA replication by 172.39, 9.92 and 55.40%. Finally, structure-activity relationships reveal that caffeoylquinic acids containing a caffeoyl group have better inhibitory activities. The results indicate that caffeoylquinic acids from L. japonica could serve as anti-HBV agents for functional food or medicinal use.