Inhibition of Fungal Endophytes by Camptothecine Produced by their Host Plant, Nothapodytes nimmoniana (Grahm) Mabb. (Icacinaceae)

Camptothecine (CPT), a monoterpene indole alkaloid, is a potent inhibitor of eukaryotic topoisomerase I. It is produced by a number of plants, including Notha-podytes nimmoniana (Grahm) Mabb. (Icacinaceae), occurring naturally in the Western Ghats, India. The plant is inhabited by a number of endophytic fungi, many of which have been isolated and shown to pro-duce CPT, in culture, independent of the host. In this article, we examine the sensitivity of endophytic fungi isolated from N. nimmoniana to CPT. Contrary to our hypothesis that these fungi should be resistant to CPT (as they are exposed to host CPT as well as that pro-duced by themselves), we report that these fungi are sensitive and thus inhibited by CPT. We discuss these results in the context of the role of CPT in limiting endophytic fungal growth.