Establishment of root suspension culture of Plumbago zeylanica and enhanced production of plumbagin

Plumbagin found in the roots of Plumbago zeylanica L. possesses various biological activities like anticancer, antibacterial, anti-inflammatory, etc. In this investigation, roots were initiated from P. zeylanica nodal explants, highest root number (24.1 +/- 0.73) was achieved in Murashige and Skoog MS media + 1 mg/L indole-3-butyric acid (IBA) whereas maximum root length (3.33 +/- 0.53 cm) was observed in MS media + 2 mg/L indole-3-acetic acid (IAA). MS liquid medium containing 1 mg/L IBA was used for establishing root suspension culture. Optimization of culture parameters reveals that half strength liquid MS media + 3% sucrose + 2 g/L inoculum density resulted in highest plumbagin production. Application of different concentrations of abiotic (yeast extract and malt extract) and biotic elicitors (methyl jasmonate and salicylic acid) enhanced plumbagin content significantly. Up to threefold increase in plumbagin concentration was achieved by treating the root suspension culture with 150 mg/L yeast extract. Results indicate that utilization of elicitor can enhance plumbagin production as well as other phytochemicals in P. zeylanica root culture.