Cytotoxic agents from Michelia champaca and Talauma ovata: parthenolide and costunolide.

The ethanol extract of Michelia champaca and the petroleum ether extract of Talauma ovata showed activity toward the human epidermoid carcinoma of the nasopharynx test system. The active constituents were sesquiterpene lactones, identified as parthenolide (C15H20O3) and costunolide (C15H20O2). Their identities were proven by elemental analyses, PMR, IR, and mass spectral data, melting-point and mixed melting-point determinations, and comparisons with authentic samples and spectra.