In Vitro Seedlings as Dynamic Explants for Establishment of Root Cultures of Pyrenacantha volubilis Hook. for Camptothecin Production

Abstract

Pyrenacantha volubilis, an important medicinal plant, is reported to contain camptothecin (CPT), a high value anticancer compound with a global demand of USD 2.2 billion in 2008. Isolated root cultures of P. volubilis could be established using radicle-developed roots from the seeds cultured in 0.3 mg L−1 kinetin. The tap roots isolated from the germinated seeds were transferred to half-strength MS liquid media supplemented with 0.3 mg L−1 indole-3-acetic acid and 0.2 mg L−1 indole-3-butyric acid to establish isolated root cultures and were further subcultured into the same media to study the growth and CPT production over a period of 60 days at an interval of 10 days. Maximum biomass (3.34 ± 0.19 g) was obtained from roots cultured in MS liquid media augmented with 0.3 mg L−1 IAA and 0.2 mg L−1 IBA with alternating salt strength over a period of 45 (17 + 28) days. The concentration of CPT in the in vitro root-derived culture sample was estimated through HPLC and recorded as 0.135% (on g DW basis, 30th day) which is comparable to that of field grown roots (0.13%). The overall results obtained with the present experiment demonstrated the use of in vitro seedlings as a dynamic explant source for root culture establishment and the feasibility of the system for further use in the production of CPT.