Study of metabolite variability in Plumbago zeylanica Linn. collected from different localities of the Gangetic plains of india

The metabolite contents of the plants may vary with season and geographic variations, and this induces the biological potential of the plant species. The present study aimed to identify the elite chemotype(s) of Plumbago zeylanica, collected from the natural habitat of Gangetic plains on the basis of plumbagin content. The effect of intra-specific variability in the plumbagin content among the population was estimated by using high-performance thin-layer chromatography (HPTLC) densitometric method. Roots of thirteen naturally occurring populations of P. zeylanica from the entire range were collected, covering the wide topography from foothills up to the highest peak. The method developed for quantification of plumbagin was validated and found to be linear, specific and accurate with precision and accuracy. LOD and LOQ were 1.04 and 3.16 ng/spot. Precision studies (both inter-day and intra-day) were within the standard limit of API, with RSD (%) less than 3%. Quantification of plumbagin within population reveals that it varies from 0.0048 +/- 0.0005 mu g (NBP-22) to 0.1696 +/- 0.003 mu g (NBC-25) percent on per dry weight basis. Analysis of variance (ANOVA) suggests that there is a significant difference in plumbagin content among the population. UPGMA cluster analyses based on plumbagin content bifurcate the populations into two major clusters, representing the variation in metabolite content. The first major cluster having NBP-25 and NBP-18 accessions, NBP-25 having maximum plumbagin content was collected from Bankura, West Bengal. The study suggests the presence of chemotaxonomic variation among the population which may be due to the change in environmental/phytogeographical factors.