Betulinic acid [1] and platanic acid [2], isolated from the leaves of Syzigium claviforum, were found to be inhibitors of HIV replication in H9 lymphocyte cells. Evaluation of anti-HIV activity with eight derivatives of 1 revealed that dihydrobetulinic acid [3] was also a potent inhibitor of HIV replication. The C-3 hydroxy group and C-17 carboxylic acid group, as well as the C-19 substituents, contribute to enhanced anti-HIV activity. The inhibitory activity of these compounds against protein kinase C (PKC) was also examined, since a correlation between anti-HIV and anti-PKC activities has been suggested. However, there was no apparent correlation between anti-HIV activity and the inhibition of PKC among these compounds.
Bioassay-guided fractionation of roots of Beilschmiedia tsangii led to the isolation of six new endiandric acid analogues: tsangibeilin A (1), tsangibeilin B (2), endiandramide A (3), endiandric acid K (4), endiandric acid L (5), and endiandramide B (6). Also isolated were two new lignans, beilschminol A (7) and tsangin C (8), and six known compounds. The structures of 1-8 were determined by spectroscopic techniques. Compounds 3 and 6 exhibited potent iNOS inhibitory activity, with IC(50) values of 9.59 and 16.40 μM, respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.