Molecular authentication of the medicinal crop Portulaca oleracea and discrimination from its adulterants in herbal markets using PCR-restriction fragment length polymorphism (PCR-RFLP) analysis

Portulaca oleracea (PO) is a popular traditional Chinese medicine (TCM) used to cool the body and reduce toxins. Authentication of Chinese herbal medicines (CHM), such as medicinal crop PO, is important and is a key step for quality control during TCM production. Adulteration of CHM reduces the efficacy of TCM and can lead to side effects in patients. Therefore, it is urgent to develop a reliable method for the verification of CHM in the TCM market. In this study, a DNA molecular method was established for rapid authentication of PO. Herein, four molecular markers, ITS1, ITS2, rbcL, and trnL, were chosen for evaluation of the sequence similarity between PO and its frequently used adulterants. Based on the phylogenetic analysis results, ITS2 was selected as the most promising molecular marker for PO authentication. Furthermore, PCR-amplified ITS2 was used to establish an RFLP pattern to distinguish PO from its adulterants. The specific restriction enzyme HpyF3I was found to quickly and effectively distinguish PO from the commonly confused plant Bacopa monnieri (BM) and other adulterants. In conclusion, this DNA molecular method can be used for PO authentication and be practically applied to audit PO plants on the herbal market and in the field.