Chemical profiling of Nothapodytes nimmoniana populations in the Western Ghats, India for anti-cancer compound, camptothecin?

Camptothecin (CPT) is a potent anti-tumour isoquinoline alkaloid used extensively in the treatment of several cancers. Among several plant species known to contain the compound, by far the highest concentration of about 0.3% (w/w) has been reported from Nothapodytes nimmoniana, a small tree distributed in the Western Ghats, South India. With no synthetic sources of this alkaloid and with an increasing global demand, there has been a heavy dependence on naturally existing populations of N. nimmoniana. Prospecting for populations and or individuals of the species for higher yields of the alkaloid could potentially help in establishing high-yielding clonal orchards and in developing in vitro production systems and thereby relieving the pressure on natural populations. Towards this end, we have chemically profiled 148 individuals from 11 populations of N. nimmoniana in the Western Ghats, a mega-diversity hotspot in South India. CPT was estimated in stem and root bark of individual trees. There was significant variation in CPT content, both in stem and root bark samples, among the populations. Differences in CPT content among individuals did not seem to be related to either their size (age) or their geographical origin. Of the 148 individuals assayed, 23 yielded more than 1% CPT. These estimates are nearly three to eight-fold more than what has been reported hitherto in the literature. Subject to further confirmation, these ‘elite’ trees could be focused for conservation and judicious utilization through clonal multiplication, as also for deriving tissue material for in vitro production systems.