Molecular profiling of "Chirayat" complex using Inter Simple Sequence Repeat (ISSR) markers.

"Chirayat" represents a group in which different species of Swertia and some other non-Swertia species are used as local substitutes/adulterants for the Swertia chirayita. Twelve different taxa recognized under "Chirayat" complex were characterized using ISSR markers. On the basis of preliminary screening, 16 informative primers were selected for molecular profiling. All the ISSR primers generated distinct DNA amplification profiles, which could be used for identification of an individual taxon in the group. Primers with anchors at 5' end generated the most polymorphic profiles. Based on their ability to distinguish between the taxa, expressed as resolving power (Rp), primer 885 showed the highest resolving power and 855 the least. A total of 332 reproducible bands were scored and all of them were polymorphic. In the cluster analysis of Swertia SPP., based on the band data, two main clusters were observed. The first consisted of S. angustifolia and S. cordata; and the other of the remaining species of Swertia. Based on the similarity coefficient, S. lurida was closest to S. chirata. The utility of ISSR markers for the authentication of commercial crude drug samples is also demonstrated. The results show that ISSR is an efficient and reliable marker system for the molecular authentication of medicinal plants as well as commercial crude drug samples.