Influence of macro elements and nitrogen source on adventitious root growth and withanolide-A production in Withania somnifera (L.) Dunal

Withania somnifera (L.) Dunal. (Indian ginseng) is an important medicinal plant which yields pharmaceutically active compounds, namely with-anolides. This study deals with the optimisation of the adventitious root suspension culture of W. somnifera for the production of biomass and withanolide-A. We investigated the effects of macro elements (NH4NO3, KNO3, CaCl2, MgSO4 and KH2PO4) and nitrogen source [NH4+ = NO3-] of Murashige and Skoog (MS) medium on the accumulation of biomass and withanolide-A content. The highest accumulation of fresh and dry biomass (127.52 and 12.45 g L-1) was recorded in the medium with 0.5 x concentration of NH4NO3 and the highest production of withanolide-A was recorded in the medium with 2.0 x KNO3 (14.00 mg g(-1) DW). The adventitious root growth was greater when the NO3- concentration was higher than that of NH4+ and the withanolide-A production was highest in the absence of NH4+. Maximum biomass growth was achieved at NH4+ : NO3- ratio of 14.38 : 37.60, while withanolide-A production was greatest (11.76 mg g(-)1 DW) when the NH4+ : NO3- ratio was 0.00 : 18.80mM. The results of this study are useful for scale-up processes.