Authentication of the family Polygonaceae in Chinese pharmacopoeia by DNA barcoding technique

Ethnopharmacological relevance: Medicinal plants belonging to the family Polygonaceae in Chinese pharmacopoeia possess important medicinal efficacy in traditional Chinese medicines. Aim of the study: DNA barcodes are first used to discriminate the Polygonaceae in Chinese pharmacopoeia and their adulterants. Materials and methods: DNA samples, extracted from thirty-eight specimens belonging to eighteen species in Polygonaceae, were used as templates. Eight candidate barcodes were amplified by polymerase chain reaction. Sequence analysis was accomplished by CodonCode Aligner V 2.06 and DNAman V 6. Species identification was performed using MEGA V 4.0. Results: The amplification efficiency of six candidate DNA barcodes (rbcL, trnH-psbA, ndhJ, rpoB, rpoC1, accD) was 100%, while the efficiency of YCF5 and nrITS was 56% and 44%, respectively. The interspecific divergence was highest for the trnH-psbA (20.05%), followed by the nrITS (14.01%) across all species pairs. while intraspecific variation both within populations and between populations was absent (0.0%). The trnH-psbA can not only distinguish ten species of Polygonaceae in Chinese pharmacopoeia, but also recognize eight other species of Polygonaceae including their adulterants. Conclusion: Our findings show that DNA barcoding is an efficient tool for identification of Polygonaceae in Chinese pharmacopoeia and their adulterants. (C) 2009 Elsevier Ireland Ltd. All rights reserved.