Comparative analysis of the constituents of two cultivars of Dioscorea dumetorum (Kunth) Pax. and their molecular barcoding

Abstract

The edible and wild cultivars of Dioscorea dumetorum (Kunth) Pax. (Family: Dioscoreaceae) are commonly used as close substitutes in herbal markets due to their edibility and medicinal importance. Comparative study of the cultivars was done using chemical analysis of their methanol tuber extracts and by utilizing the DNA barcode regions, ribulose-1, 5-bisphosphate carboxylase subunits (rbcL) and the non-coding intergenic spacer gene (trnH-psbA) for nucleotide sequences comparison of cultivars. Of the 54 compounds identified from the methanol extract of the edible and wild cultivars using gas chromatography-mass spectrometry (GC-MS), 12 are similar, while 42 are remarkably different. In particular n-hexadecanoic (palmitic) acid had a higher percentage area in the edible cultivar (31.16%) compared to the wild cultivar (0.26%). The cultivars were successfully amplified using the universal primers gene rbcL and trnH-psbA. Their nucleotide sequences showed a slight variation when aligned with CodonCode Aligner V.9.0.1. They were identified by the Basic Local Alignment Search Tool (BLAST) through comparison with Genbank data, which shows close similarities with submitted data. The use of molecular barcoding in identifying the cultivars of Dioscorea dumetorum as well as the chemical composition of their tubers may form an important marker in the compilation of future herbal pharmacopoeia for its proper identification.