Molecular authentication of the traditional Chinese medicinal plant Euphorbia pekinensis

The ITS regions of Euphorbia pekinensis and six other Euphorbia species used as adulterants of E. pekinensis were sequenced to differentiate them. The sequences are identical among the individuals in the seven species studies. Diversity in DNA sequences among various species was found ranging from 8.3% to 43.8% in ITS1 and 7.6% to 36.6% in ITS2 region. Furthermore, based on the divergent ITS regions, species-specific primers, JDJp 1 and JDJp 2, were designed in the polymorphic regions of E. pekinensis to distinguish it from adulterants. These ITS-derived primers amplified a 281-bp-specific DNA fragment from E. pekinensis. No amplified product was observed using DNA of six adulterants.