Detection of Molecular and Phytochemical Variations in Tamilnadu Landraces of Gymnema sylvestre Genotype: An Important Anti-Diabetic Plant

Gymnema sylvestre, a potential anti-diabetic medicinal plant, is used in many herbal drug formulations. The medicinal properties have been credited to the presence of gymnemic acid, which is effective in controlling blood glucose and lipid levels in the body. Molecular and biochemical variations of seven populations of G. sylvestre were investigated using DNA markers and phytochemical fingerprints of gymnemic acid content. Results obtained through these techniques were used in a comparative analysis and revealed a correlation between genetic variations and biochemical content analysis. Thirteen primers were used for RAPD-PCR analysis revealing 112 bands, of which 62 were found to be polymorphic. The percentage of polymorphic bands detected ranged from 11.1 to 84.6% with an average of 54.2%. The average number of amplified bands per primer was 8.62 while the mean number of polymorphic bands per primer was 5.42. A dendrogram of the genetic similarities among the populations was constructed using the genetic distance coefficients and the seven accessions were clustered into four major groups. The total gymnemic acid content level varied significantly among these groups from 3.84 to 7.12 mg g-1 DW. A principle coordinate analysis confirmed the results of clustering. Maximum yield of gymnemic acid content (7.12 mg g-1 DW) was recorded with L7 accession. Results suggest that there might be a positive correlation between genetic makeup and gymnemic acid content; however, this has to be further investigated by using other molecular approaches.