Determination of Metabolic and Genetic Diversity in Coleus forskohlii Briq. Using HPTLC and RAPD Analysis
Coleus (Coleus forskohlii Briq.) belongs to the family lamiaceae and is known for its forskolin content, which has been demonstrated to possess hypotensive, spasmolytic, cardiotonic and antiplatelet activity. The dominant polymorphism between individual samples/races are indicated by the presence or absence of a particular RAPD fragment and extensively applied for assessing genetic diversity and relationship measures in various plant species. However, use of chromatographic fingerprint in analysis of metabolite diversity similar to RAPD in molecular markers is uncommon and can be easily done by developing multiple fingerprints using different solvent systems and analyzing them for determination of metabolic similarity in between species. Simultaneous, metabolic and genetic diversity has been attempted by the authors for first time using HPTLC fingerprints and RAPD markers, respectively. Genetic analysis of 10 different samples of C. forskohlii genotypes was performed using 20 RAPD primers, based on an efficient protocol for isolation of genomic DNA from dried root of coleus. Chromatographic analysis was carried out using three different mobile phases and pre-coated aluminum back TLC sheets as stationary phase. A similarity matrix was constructed using molecular and chromatographic fingerprint data based on Jaccard's coefficient and further subjected to construct dendrogram based on UPGMA. The similarity coefficient for genetic nature ranged from 0.362 to 0.783 while for metabolic profile it was between 0.683 to 0.939. This indicates a genetic diversity in C. forskohlii samples but a lesser chemical diversity among the same samples.
Acknowledgements: Thanks go to UGC and DST, government of India