Leoidin is a depsidone originally isolated from L. gangaleoides that has antibacterial and enzyme inhibitory activities.1,2,3 It is active against the bacteria E. faecalis, H. influenzae, M. catarrhalis, S. aureus, and S. pneumoniae (MICs = 8, 32, 1, 128, and 64 μg ml, respectively).2 Leoidin inhibits phenylalanyl-tRNA synthetase (PheRS) isolated from P. aeruginosa (IC50 = 42 μM). It also inhibits organic anion-transporting polypeptide 1B1 (OATP1B1) and OATP1B3 with Ki values of 0.08 and 1.84 μM, respectively, in CHO cells expressing the human transporters.3
Euphol acetate, a triterpene found in Euphorbia broteri, has demonstrated inhibitory effects on the hepatic transport proteins known as organic anion-transporting polypeptide 1/3 (OATP1B1/3).