摘要
A new tetracyclic triterpenoid compound named as mastichinoic acid A (1) was isolated from Mastich. The structure was established as 3,7-dioxo-11-hydroxy-5-tirucalla-8,24(Z)-dien-26-oic acid by various spectroscopic techniques including MS, 1D, and 2D NMR and HRTOFMS.