Effect of seaweed elicitation and culture conditions on biomass and metabolite production in in vitro shoots of Withania somnifera

Abstract

Withania somnifera is an important medicinal plant used in various herbal preparations due the presence of its key metabolites-withanolides. The present study focuses on the effect of seaweed extract and different in vitro culture conditions on the biomass and key metabolite content in in vitro shoot cultures of Withania somnifera . The commercially available seaweed extract powder of Kappaphycus alverizii with the trade name ’Magic vita - P’ was examined for its effect on solid, suspension and bioreactor cultures of Withania somnifera. The standardisation of elicitation conditions showed the exposure of shoot cultures to 0.25% seaweed extract for 7 days resulted in maximum biomass and withaferin A content which were 1.91 fold and 3.05 fold higher than that of untreated shoots. Further among the three culture conditions studied, the bioreactor cultures exhibited maximum growth index compared to the solid and suspension cultures thus producing maximum biomass which in turn resulted in higher accumulation of withanolides per batch of culture. Thus the seaweed treated shoots in bioreactor yielded 18.56, 8.96, and 7.29 fold increase in withaferin A, withanolide A and withanone content compared to control shoots in solid media. Further the effect of this elicitation and culture conditions on the accumulation pattern of the primary metabolites were studied using GC-MS. The Principal Component Analysis (PCA) of the GC-MS data exhibited a clear distinction between the control and seaweed treated samples. Thus our findings indicate a clear protocol for scaling up of withanolide production from in vitro shoot cultures of Withania somnifera . Withania somnifera being a traditional medicinal plant with wide array of medicinal properties poses a great demand in the international market. Hence there arises a need for alternate culture techniques to meet its rising demands which is still increasing past the COVID-19 pandemic. Thus this paper focuses on in vitro technique for mass production of Withania somnifera shoots. This main highlights of the paper includes: • Effect of a seaweed (organic fertilizer) on biomass and withanolides production in in vitro shoots of Withania somnifera. • The influence of various culture techniques on the biomass and metabolite production in in vitro shoots of Withania somnifera. • Correlation among the primary metabolites as obtained from the GC-MS analysis with that of withanolide content obtained using HPTLC technique.