Biosynthesis of Camptothecin from Callus and Cell Suspension Cultures of Ophiorrhiza mungos L. var. angustifolia (Thw.) Hook. f

Ophiorrhiza mungos var. angustifolia is a herbaceous plant distributed in the southern western ghats of India. The species is extensively uprooted for the extraction of high-value anticancer alkaloid camptothecin (CPT), resulting in the eradication of natural population. The present work aims to develop an in vitro protocol for the sustainable production of CPT from callus and cell suspension cultures of the species to conserve the natural resource. Leaf explant excised from in vitro shoot cultures was inoculated onto solid half-strength Murashige and Skoog medium, fortified with auxins like Indole acetic acid (5.71–26.83 µM), Indole butyric acid (4.92–24.6 µM), Naphthalene acetic acid (5.71–28.54 µM), 2,4 Dichlorophenoxyacetic acid (4.52–22.62 µM) and Picloram (4.14–20.70 µM); either individually or in combination with Benzyl adenine, to raise the callus. Of the different combinations of auxins, 10.74 µM Naphthalene acetic acid + 4.44 µM Benzyladenine was selected as the best combination to produce maximum fresh weight of callus. The CPT content of callus was estimated as 0.23 ± 0.03 mg/g DW. Friable calli produced were used to raise cell suspension cultures in half strength MS liquid medium, fortified with different concentrations of auxins. Maximum fresh weight was yielded by a medium supplemented with 16.12 µM Naphthalene acetic acid (14.64 ± 2.03 g). Highest CPT content was estimated in a medium supplemented with 10.74 µM Naphthalene acetic acid as 0.31 ± 0.01 mg/g DW. When compared with the CPT content of field plants, it was found to be higher.