Authentic identification of stigma Croci (stigma of Crocus sativus) from its adulterants by molecular genetic analysis.

Stigma Croci, stigma of Crocus sativus L., is a precious traditional Chinese medicine, which is commonly used to activate blood circulation and to dissipate blood stasis. Three plant species, Carthamus tinctorius L., Hemerocallis fulva (L.) L. and Hemerocallis citrina Baroni, could carry the name Stigma Croci in the commercial markets of South East Asia. However, C. sativus is the only one that has proven its effectiveness, while the others could act as adulterants. The authentic identification of C. sativus on the market is difficult. By using molecular genetic method, the spacer domains of 5S-rRNA were cloned from the genomic DNAs that were isolated from C. sativus, C. tinctorius, H. fulva and H. citrina. The cDNAs encoding the spacer domains, about 300 to 500 bp, were sequenced. The nucleotide sequences of these four species showed great diversity, which could serve as markers for authentic identification of Stigma Croci to distinguish from its substitution and counterfeit.