Triterpenes from Isodon xerophilus

AIM: To investigate the chemical constituents of Isodon xerophilus. METHODS: The constituents were isolated by various chromatographic methods, and the chemical structures were elucidated on the basis of spectral analyses. Their cytotoxicity was evaluated by the MTT method in 96-well microplates. RESULTS: Ten triterpenes were isolated and identified as oleanolic acid (1), ursolic acid (2), maslinic acid (3), 2 alpha-hydroxyursolic acid (4), hederagenin (5), 3 beta, 23-dihydroxy-urs-12-en-28-oic acid (6), arjunolic acid (7), asiatic acid (8), 2 alpha, 3 alpha, 24-trihydroxyolean-12-en-28-oic acid (9), and 2 alpha, 3 alpha, 24-trihydroxyurs-12-en-28-oic acid (10). All compounds were tested against three human tumor cell lines, K562, MKN45, and HepG2. CONCLUSION: All of the compounds were isolated from this plant for the first time. The proposed biosynthetic pathway of these triterpenes was discussed. All of the triterpenes showed noncytotoxic activity against the above-mentioned three human tumor cell lines.