Abstract
Ruta graveolens L. (Rutaceae) is commonly known as 'Sudab' which is well known for hippocratic medicine and is commonly used in indigenous health-care system in India. Euphorbia dracunculoides Lam. (Euphorbiaceae) in raw drug trading has almost similar morphology to R. graveolens in dried state, is being sold locally or used clinically as an adulterant of R. graveolens (genuine) at a relatively low price under the same name 'Sudab' which has ultimately reduced the efficacy and quality of this herb. The internal transcribed spacer (ITS) sequence of nuclear ribosomal DNA gene of genuine and adulterant were sequenced and analyzed to assess species admixture in raw drug trading of genuine herbal drug. The BLAST search results of ITS sequence of genuine sample of 'Sudab' i.e., R. graveolens showed 99% similarity to the sequence of R. graveolens, however, E. dracunculoides showed 100% similarity to the species of Euphorbia and did not show any similarity with R. graveolens. The sequence alignment of both species was entirely different to each other. Phylogenetic analysis based on ITS sequence of adulterant sample i.e., E. dracunculoides together with sequences of Euphorbia species available in the GenBank has also clearly showed its nesting within the Euphorbia tree. The generated ITS sequences of both samples in the present study may be referred hereafter as species-specific DNA barcode signature, which can be used in authenticating and validating the exact species identities to discriminate the genuine sample of 'Sudab' from its adulterants if any available to guarantee the quality and purity of this drug in the herbal drug market.