Bioactivity-guided fractionation of the CHCl3 extract from hooks of Uncaria
rhynchophylla led to the isolation of two triterpene esters, namely uncari
nic acids A (1) and B (2). Their structures were established by spectroscop
ic and chemical methods. These compounds inhibited phospholipase C gamma l
with IC50 values of 35.66 and 44.55 mu M, respectively. (C) 1999 Elsevier S
cience Ltd. All rights reserved.