Molecular Authentication of Medicinal Plant, Swertia chirayita and its Adulterant Species

Abstract

Swertia is ethno-medicinally an important genus belonging to family Gentianaceae. Swertiachirayita is used as imperative medicinal plant in Indian system of medicine. However, this species has been frequently adulterated due to its high demand and scarcity. Authentication of this species was needed to protect consumers and conservation measures and to find out the alternative source. Deoxyribose nucleic acid (DNA) extracted from fifteen samples of six species belonging to different localities, were used as templates. Four candidate barcodes were amplified by polymerase chain reaction and sequence analysis was executed by Z-Big Dye Terminator Cycle Sequencing v.3. Sequenced products were analyzed on automated applied biosystems 3730XI analyzer. Identification was performed by using molecular evolutionary genetics analysis 5 software (version 5.1). The amplification efficiency of all DNA barcodes [megakaryocyte-associated tyrosine kinase (matK), ribulose-bisphosphate carboxylase (rbcL), photosystem II protein D1- stuctural RNA- His tRNA (psbA-trnH) and internal transcribed spacer region (ITS)] was 100 %. Here, the highest interspecific divergence provided by ITS is 11.87 % and intraspecific by psbA-trnH being 10.22 % as compared to matK (5.04 %) and rbcL (0.99 %). ITS region proves robust molecular marker for differing the S. chirayita from its related adulterant species. All barcoding regions indicate that S. chirayita and S. minor both are more closely related than other Swertia species. Findings showed that DNA barcoding is an efficient tool for identification and authentication of S. chirayita. Use of S. minor as substitute to S. chirayita can be advocated.