Synthesis of withanolide A depends on carbon source and medium pH in hairy root cultures of Withania somnifera

Abstract

Withania somnifera (L.) Dunal. (Indian ginseng) is an important medicinal plant which yields pharmaceutically active compounds called withanolides. The present work deals with optimization of parameters of hairy root culture of W. somnifera for the production of biomass and withanolide A. We also investigated the effects of carbon source [sucrose, glucose, fructose, maltose, glucose + fructose (1:1), fructose + sucrose (1:1) and sucrose + glucose (1:1)], sucrose concentration (1%, 2%, 3%, 4%, 6% and 8%) and the initial medium pH (4.0, 4.5, 5.0, 5.5, 5.8, 6.0 and 6.5) on growth and production of withanolide A in hairy root cultures of W. somnifera. We found that biomass accumulation and production of withanolide A was highest when sucrose was used as the carbon source (11.92 g l −1 DW and 11.96 mg g −1 DW of withanolide A). Further 3% sucrose concentration was found to be optimal for biomass accumulation (11.92 g l −1 DW) and 4% sucrose favoured the production of withanolide A (13.28 mg g −1 DW) in the tested range of concentrations (1–8%). The biomass of hairy roots was optimal when the initial medium pH was 5.8 (12.1 g l −1 DW) and the withanolide A production was highest in the medium pH set at 6.0 (13.84 mg g −1 DW).