Establishment of adventitious root cultures from leaf explants of Plumbago rosea and enhanced plumbagin production through elicitation

Adventitious root cultures of medicinal plants are considered as a source of raw material for pharmaceutical industries. The roots of Plumbago rosea are used in various ayurvedic preparations for treating several diseases. Plumbagin is the major bioactive compound in the roots and it possesses activities against HIV and different types of cancers. Direct adventitious root initials were initiated on leaf explants of P. rosea, in Murashige and Skoog semisolid media supplemented with 1.5 mg L-1 indole-3-acetic acid (IAA) and 1 mg L-1 indole-3-butyric acid (IBA) and was used to establish root suspension cultures. Culture parameter optimization experiments showed that 3/4th strength MS liquid media with 30% sucrose and 2 g L-1 (FW) root inoculum was optimum for maximum biomass production. Without elicitation, maximum plumbagin production was obtained in media containing 0.5 mg L-1 IBA and 0.1 mg L-1 GM. The study suggests that fast growing and high yielding adventitious roots could be established from leaf explants by optimizing the culture conditions for root induction and growth. Elicitation with different concentrations of elicitors such as jasmonic acid, yeast extract and sodium salicylate showed that 50 mu M jasmonic acid for three days significantly increased plumbagin content in roots to 1.23% DW. The results reveal that elicitation is a good strategy for enhancing the plumbagin content in adventitious root cultures. (C) 2015 Elsevier B.V. All rights reserved.