Bioactive Triterpenoids from the Leaves and Twigs of Lithocarpus litseifolius and L. corneus

Abstract

Phytochemical investigation of the leaves and twigs of <i>Lithocarpus litseifolius</i> and <i>Lithocarpus corneus</i> resulted in the isolation of four new triterpenoids (1: -4: ), three triterpenoids (5: -7: ) isolated from a natural source for the first time, and six known compounds (8: -13: ). In addition, four known triterpenoids (14: -17: ) were isolated from <i>L. corneus</i>. Compound 1: is a 3,4-<i>seco</i>-lupane-type triterpenoid, and compounds 2: -4: are lupane-type triterpenoids in different oxidation states. The structures of all isolated compounds were identified by spectroscopic methods, especially NMR and mass spectrometry data. The absolute configuration of 2: and 3: was confirmed by X-ray single crystallographic analysis. The anti-inflammatory activities of 1: -17: and anti-HIV activities of 2: -17: were evaluated. Among them, 3-<i>epi</i>-betulinic acid (8: ) showed a strong anti-HIV activity comparable to abacavir, a drug used for treating HIV/AIDS. 3,4-<i>seco</i>-4(23),20(29)-lupadiene-3,28-dioic acid (5: ) exhibited potent inhibition of superoxide-anion generation with 86.9 ± 2.8% inhibition at 1 µM.