Rapid identification of medicinal leech by species-specific polymerase chain reaction technology

Background: Leech is a well-known animal-derived Chinese medicine; intentionally or unintentionally, interfusing fake products have exposed patients to high risk. Objective: In this study, we would like to find a rapid and accurate technology to identify medicinal leech. Materials and Methods: Three sets of species-specific primer were designed, and polymerase chain reaction (PCR) conditions were optimized for the four species analyzed. Specificity and sensitivity test were carried out, and the reference sample mixtures were analyzed. Finally, the developed method was used to assess the authenticity of commercially available products. Results: Three sets of species-specific primer were confirmed to have high interspecies specificity and good intraspecies stability. The limit of detection was estimated to be 1 ng for all of four assayed species. Subsequent validation demonstrated that the raw material, processed, and even highly processed products of leech can be conveniently authenticated with good sensitivity and precision by this newly established PCR-based method. Conclusion: These designed novel primer sets have shown distinct performance on the identification of adulterate products. The new technology needs no procedure for sequencing and has been successfully employed for the reliable authentication of raw material of leech and even their processed and highly processed products.