Assessment of diversity amongst natural populations of Gymnema sylvestre from India and development of a validated HPLC protocol for identification and quantification of gymnemagenin

Abstract

In order to supply uniform, genuine, good quality raw material to the pharmaceutical industries and to reduce the burden on natural stocks, cultivation of medicinal crops is the need of the hour. However, improved varieties with optimum levels of active ingredients have so far not been developed in a number of important medicinal crops. Considering this, an investigation was undertaken to assess the extent of variability amongst the natural populations of Gurmar (Gymnema sylvestre), an important anti-diabetic plant of the Indian Systems of Medicine. Evaluation of the accessions for morphological parameters revealed highly significant differences for leaf related parameters viz. length, width, fresh as well as dry weight and petiole length, which directly contribute to the biological yield of the plant. Further, a validated high performance liquid chromatography-diode array detection (HPLC-DAD) method was also developed for identification and quantification of bioactive principle i.e., gymnemagenin in a gradient elution mode using solvent mixture composing of acetonitrile (solvent A), potassium dihydrogen orthophosphate (10mM, solvent B) both solvent A and B containing orthophosphoric acid (0.05%, v/v). Results revealed significant differences for gymnemagenin content amongst the accessions evaluated. These accessions could be used in breeding programs for development of cultivars with optimum levels of gymnemagenin, which in turn may promote the cultivation of this high value medicinal crop.