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 Chines e medicine, which is commonly used to activate blood circulation and to dis sipate blood stasis. Three plant species, Carthamus tinctorius L., Hemeroca llis fulva (L.) L. and Hemerocallis citrina Baroni, could carry the name St igma 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 marke t 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 domai ns, about 300 to 500 bp, were sequenced. The nucleotide sequences of these four species showed great diversity, which could serve as markers for authe ntic identification of Stigma Croci to distinguish from its substitution an d counterfeit.