Assessment of chemical diversity in Clitoria ternatea accessions by an improved and validated HPTLC method

Abstract

Evaluation of chemical diversity among genotypes of medicinal plants plays a pivotal role for its improvement and large scale cultivation. Chemical variability of bioactive principles, viz. taraxerol and β-sitosterol are analyzed in 11 populations of Clitoria ternatea L., an important memory enhancer used in Ayurveda. The study revealed high diversity among the collected samples with concentrations (mg/g on dry weight basis) ranging from 0.358±0.006 to 1.04±0.024 mg/g and 0.183±0.004 to 0.334±0.009 mg/g for taraxerol and β-sitosterol, respectively. The chemical variation was examined for different accessions under the same cultivation and environmental conditions during the years 2014 and 2015 at DMAPR, Anand, Gujarat, India. Selection of elite accession was made possible by screening germplasm collected from various parts of India. The results of the experiment refute the popular belief that plants with white flowers are superior to blue flower on phytochemical content basis. Further a validated HPTLC method was developed for the simultaneous determination of taraxerol and β-sitosterol from the species. The method was also applied to study the effect of solvent and plant parts to achieve enhanced active ingredient extract. Results showed that petroleum ether is the most effective solvent for extraction of the two major pharmacologically active constituents, viz. taraxerol (126±4.368 μg/mg of root extract) and β-sitosterol (13.2±1.706 μg/mg of root extract) due to enriched content with high purity root extract of C. ternatea.