Seaweed extract as a novel elicitor and medium for mass propagation and picroside-I production in an endangered medicinal herb Picrorhiza kurroa

Abstract

Picrorhiza kurroa is an endangered medicinal herb, used in the preparation of herbal drugs,mainly due to the presence of two iridoid glycosides, picroside-I (P-I) and picroside- II (P-II). Its over exploitation necessitates the development of conservation strategies and enhanced production of secondary metabolites. In present study, effect of seaweed extract (SWE) with and without growth hormones was studied for in vitro propagation and production of P-I in P. kurroa. Murashige and Skoog (MS) media supplemented with SWE (MSS) showed 3.23, 1.55, 2.42, 2.52 and 2.41 folds enhancement in total plant biomass, total plant length, number of shoots, root length and number of roots, respectively after 1 month as compared to control C1(MS ? sucrose ? agar). MSS with growth hormones showed increment of 1.92, 1.14, 1.47, 1.43 and 3.53 folds in total plant biomass, total plant length, number of shoots, root length and number of roots, respectively as compared to control CM (MS ? sucrose ? growth hormones ? agar) after 1 month. SWE media (SWM) showed comparable results and proved to be an economic alternative to MS media. Both MSS and SWM increased P-I accumulation by 3–4 folds and 2–3 folds at 25 ± 2 and 15 ± 2 C, respectively. Expression of 1-deoxy-D-xylulose 5-phosphate synthase and 3-hydroxy-3-methylglutaryl- CoA reductase, key enzymes of non-mevalonate and mevalonate pathways were up regulated vis-a´-vis metabolite content. This is the first report demonstrating the potential of SWE as an elicitor for enhanced growth and P-I production besides being an alternative to MS media for large scale micropropagation of P. kurroa.