Exogenous methyl jasmonate acts as a signal transducer in the enhancement of camptothecin (CPT) production from in vitro cultures of Ophiorrhiza mungos L. var. angustifolia (Thw.) Hook. f.

Abstract

Ophiorrhiza mungos var. angustifolia is a member of Rubiaceae family can be a gold standard for the in vitro production of high-value anticancer compound camptothecin to meet the increasing market demand for medicine. Multiple shoot cultures of Ophiorrhiza mungos var. angustifolia was induced in the nodal explant using half-strength Murashige and Skoog solid media supplemented with different concentrations of cytokinins (4.44–22.19 μM Benzyl adenine and 4.65–23.23 μM Kinetin either individually or in combination) and auxins (4.92–24.6 μM Indole butyric acid, 5.37–24.6 μM Indole acetic acid and 5.71–28.54 μM in combination with Benzyl adenine) for three weeks. Among the plant growth regulators treated, benzyl adenine (8.88 μM) was found to be the most effective in multiple shoot induction (22 ± 3.90 shoots/explant), thus further shoot multiplication is achieved in fresh media with the same composition. Increased camptothecin production is achieved by the elicitation of multiple shoots using methyl jasmonate (50, 100, 150 and 200 μM), salicylic acid (50, 100, 150 and 200 μM) and chitosan (10, 50,100 and 150 mg/l) separately under a different period of incubation. The results showed 7 fold increase in the production of camptothecin (0.74 ± 0.05 mg/g dry weight of shoots) in shoots elicited with 150 μM methyl jasmonate for 72 h compared to the control. (0.14 ± 0.01 mg/g dry weight of shoots). Additional shoot bud formations were not observed irrespective of elicitor used. Camptothecin was estimated using high-performance liquid chromatography. The results obtained in the present experiment clearly demonstrate and strongly endorse the suitability of using Methyl jasmonate as a promising and reliable elicitor for enhanced production of camptothecin in Ophiorrhiza mungos var. angustifolia.