HPLC analysis of Withania somnifera (Linn.) Dunal reveals two chemotypes in Indian germplasm and seasonal and genetic variability in Withaferin A -Content

HPLC methods for profiling and estimation of withanolide in Withania have been developed to study seasonal, geographical and genetic variation in Withaferin-A content and identify chemotypes. Highest withanolide content was observed during the vegetative phase and slight decrease was observed during reproductive phase. However, the content drastically reduced at the maturity. No significant effect of location was observed on the withanolide content when same genotypes were grown at two diverse locations. Withaferin-A content in Indian population of Withania somnifera varied from 0.22 to 3.38 % with a mean value of 1.099 in the leaves during vegetative stage.Whereas during maturity the content ranged from 0.0056 to 1.99 % with a mean value of 0.5942 %. In the roots, Withaferin-A content ranged from 0.0028 to 0.75 % with a mean value of 0.1242 during vegetative phase and 0.0008 to 0.1489 with a mean value of 0.00213 % at maturity of the plant. The population segregated into two chemotypes identified as chemotype-I and as an intermediate of Chemotype-I and Chemotype-II.