Siphonodon celastrineus Griff. (Celastraceae) is a tree that grows up to 25 m. in height and is found in the northern and central parts of Thailand. In Thai traditional medicine, its roots are used for the treatment of inflammation, abscesses, skin diseases, and as a bone tonic [1]. Recently, an ethanolic extract of the leaves of S. celastrineus showed cytotoxic activity against the MCF-7 cancer cell line with an IC 50 value of 17.1 µg/mL [2]. Subsequent chemical investigations of the root bark of this plant revealed the presence of the oleanane triterpene and the quinone methide triterpene from the methanolic extract [3] . Preliminary screening of dichloromethane extract of the stem of this plant in our laboratory showed cytotoxic activity against the MOLT-3 cancer cell line (86% cytotoxicity at 10 µg/mL). The chemical and biological properties of this plant were thus further investigated. In this presentation, the isolation and structure elucidation of forty-one new triterpenes consisting of a lupine, two friedelane, two oleanane, and thirty-six ursane - type triterpenoids, together with nine known compounds were isolated from the stem of S. celastrineus. The structures were characterized by various spectroscopic techniques, comparison with literature data, and chemical transformation. Several compounds were evaluated for their cytotoxic activity against six human cancer cell lines (MOLT-3, HuCCA-1, A549, HeLa, HepG2, and MDA-MB-231).
References
- Chayamarit K. Thai medicinal plants Part 4. Bangkok: Chutima Publishing; 1985: 330 - 332.
- Itharat A, Houghton PJ, Eno-Amooquaye E, Burke PJ, Sampson JH, Raman A. J Ethnopharmacol 2004; 90: 33 - 38.
- Niampoka C, Suttisri R, Bavovada R, Takayama H, Aimi N. Arch Pharm Res 2005; 28: 546 - 549.