Effects of forsythia fruit extracts and lignan on lipid metabolism.

A primary methanol extract (F-ME), secondary butanol-soluble fraction (F-BU), and lignans were prepared from forsythia fruit (Forsythia viridissima L.) and added to 0.5% (w/w) cholesterol diets for male Sprague-Dawley rats weighing 121 +/- 12 g. There were six experimental groups: a control group, 0.2%, 0.4% F-ME supplemented groups, 0.1%, 0.02% F-BU groups and 0.02% lignan group. After 3 weeks of feeding, body weight gains, serum GOT and GPT levels were not different among the groups. HDL-/total cholesterol ratios increased in the 0.2% F-BU and lignan groups compared with the control groups. Liver triglyceride level lowered in most of forsythia groups. Fecal cholesterol excretions increased in the lignan group. Arctiin isolated from the forsythia fruit reduced cholesterol and triglyceride contents in cultured HepG2 cells at 0.01-0.1 microM. These results indicated that the forsythia lignan, arctiin is effective on improving blood lipid status without a significant hepatotoxicity and is to be utilized for the functional foods for lipid-lowering action.