RESUMO
Camptothecine, a potent eukaryotic topoisomerase inhibitor, is an important anticancer compound. The global demand for this compound was estimated to be $1 billion in 2003 and is only further expected to increase. Partly to meet the expected increase in demand, in the recent past, several efforts have been made to discover newer and alternative plant and fungal sources of camptothecine. In this study we report a rich source of camptothecine and its natural derivatives, Pyrenacantha volubilis (Icacinaceae) from the eastern coast of peninsular India. Camptothecine and its derivatives were analyzed using high performance liquid chromatography (HPLC) coupled with electrospray mass spectrometry (ESI-MS) in all plant parts such as twigs, leaves, roots, seedling, ripened whole fruit, fruit coat, seed coat and cotyledons. Cotyledons and ripened whole fruits contained the highest amount of camptothecine (1.35% and 0.60% dry weight respectively). LC-MS and ESI-MS/MS analyses revealed besides camptothecine, other derivatives and precursors such as 10-hydroxycamptothecine, 9-methoxycamptothecine, 20-deoxycamptothecine, deoxypumiloside, strictosidine and strictosamide. Pure camptothecine was isolated from fruits and structurally confirmed using NMR. Seed extracts were found to be effective against breast cancer, ovarian, colon and carcinoma cell lines (with IC50 values of 4.0 µg/mL, 6.5 µg/mL, 25.0 µg/mL and 25.0 µg/mL respectively). We discuss the results in the context of exploring alternative sources of camptothecine.
