Triterpenes from the stem bark of Mitragyna diversifolia and their cytotoxic activity

To study the chemical constituents and bioactivity of the stem bark of Mitragyna diversifolia.

Compounds were isolated by various chromatographic methods. Their structures were elucidated on the basis of spectroscopic techniques (IR, UV, MS, and NMR), and they were evaluated for their cytotoxic activities by the MTT method.

Eight triterpenes were isolated and identified as 3α, 6β, 19α-trihydroxy-urs-12-en-28-oic acid (1), 3β, 6β, 19α-trihydroxy-urs-12-en-28-oic acid (2), 3-oxo-6β-19α-dihydroxy-urs-12-en-28-oic acid (3), 3β, 6β, 19α-trihydroxy-urs-12-en-24, 28-dioic acid 24-methyl ester (4), 3β, 6β, 19α, 24-tetrahydroxy-urs-12-en-28-oic acid (5), rotundic acid (6), 23-nor-24-exomethylene- 3β, 6β, 19α-trihydroxy-urs-12-en-28-oic acid (7), and pololic acid (8), respectively. All of the isolates were tested against two human tumor cell lines, MCF-7 (breast) and HT-29 (colon).

Compound 1 was a new triterpene. Compounds 5 - 7 exhibited potent inhibitory effects on the growth of MCF-7 and HT-29 cells, and the others showed no cytotoxicity.