Identification of Crocus sativus (Iridaceae) and its adulterants by using DNA barcoding technique

Saffron (Crocus sativus), called Zang-Hong-Hua in Chinese, is a traditional but very expensive herbal medicine. As an important traditional medicine, it has an outstanding effect in treating irregular and painful menstruation. Due to the high market demands of saffron, however, it has frequently been misused, adulterated or intentionally introduced in medicinal markets, pharmacies or online stores. In this study, 13 samples were collected from 12 different provinces of China, and the other four substitutions' information downloaded from Genbank. Through DNA barcoding methods, we compared different samples by using three candidate markers, trnH-psbA, rbcL-a and ITS2 sequences. As a result, four samples collected from Hebei, Shandong, Fujian and Yunnan provinces were potentially mislabeled. We concluded that the trnH-psbA and rbcL-a can distinguish different accessions of Crocus sativus, while the ITS2 can differ it from the substitutes and adulterants. For ITS2 barcode, it can identify samples even at intraspecific level. This study demonstrated that DNA barcodes are the powerful tool for the identification of medicines to the species level.