Leoligin, the major lignan from Edelweiss, activates cholesteryl ester transfer protein

OBJECTIVE: Cholesteryl ester transfer protein (CETP) plays a central role in the metabolism of high-density lipoprotein particles. Therefore, we searched for new drugs that bind to CETP and modulate its activity. METHODS: A preliminary pharmacophore-based parallel screening approach indicated that leoligin, a major lignan of Edelweiss (Leontopodium alpinum Cass.), might bind to CETP. Therefore we incubated leoligin ex vivo at different concentrations with human (n=20) and rabbit plasma (n=3), and quantified the CETP activity by fluorimeter. Probucol served as positive control. Furthermore, we dosed CETP transgenic mice with leoligin and vehicle control by oral gavage for 7 days and measured subsequently the in vivo modulation of CETP activity (n=5 for each treatment group). RESULTS: In vitro, leoligin significantly activated CETP in human plasma at 100 pM (p=0.023) and 1 nM (p=0.042), respectively, whereas leoligin concentrations of 1 mM inhibited CETP activity (p=0.012). The observed CETP activation was not species specific, as it was similar in magnitude for rabbit CETP. In vivo, there was also a higher CETP activity after oral dosage of CETP transgenic mice with leoligin (p=0.015). There was no short-term toxicity apparent in mice treated with leoligin. CONCLUSION: CETP agonism by leoligin appears to be safe and effective, and may prove to be a useful modality to alter high-density lipoprotein metabolism.