Molecular authentication of the Oriental medicines Pericarpium citri reticulatae and Citri unshius pericarpium using SNP markers.

Pericarpium citri reticulatae and Citri unshius pericarpium are important Oriental medicinal materials used in many prescriptions. Among the Citrus species, the dried peels of C. japonica, C. maxima, and C. trifoliata are found to be adulterants and substitutes of Pericarpium citri reticulatae and Citri unshius pericarpium. In order to develop a simple and reliable DNA method for authentication of these two medicinal materials, nuclear ribosomal internal transcribed spacer (ITS) region was targeted for molecular analysis. A host of single nucleotide polymorphism (SNP) sites were detected among ITS sequences of five Citrus species. From two SNP sites, two modified specific primers were designed for authentication of Pericarpium citri reticulatae and Citri unshius pericarpium using multiplex PCR. The established multiplex allele-specific PCR system was proven to be effective for simultaneous authentication of Pericarpium citri reticulatae and Citri unshius pericarpium. The scheme used in this study could be adapted for determination of the botanical identity and origin of other medicinal materials.