Inhibition of phospholipase cgamma1 and cancer cell proliferation by triterpene esters from Uncaria rhynchophylla

Abstract

Investigation of the hooks of Uncaria rhynchophylla resulted in isolation of six phospholipase Cγ1 (PLCγ1) inhibitors (1-6). The structures of these compounds were elucidated as pentacyclic triterpene esters by spectroscopic and chemical analysis. Three of them, namely uncarinic acids C (1), D (2), and E (3), are newly reported as natural products. All the compounds showed dose-dependent inhibitory activities against PLCγ1 in vitro with IC50 values of 9.5-44.6 μM and inhibited the proliferation of human cancer cells with IC50 values of 0.5-6.5 μg/mL.