DNA barcoding of Gentiana crassicaulis in Lijiang and evaluation of root processing methods / 药学学报

ABSTRACT

The key factors for producing the best quality Chinese herbal medicines are high-quality germplasm, suitable cultivation area and the proper processing methods for herbal raw materials. Gentiana crassicaulis in Gentiana (Sect. Cruciata), Gentianaceae is one of the original plants of the Chinese herb Qinjiao (Gentianae Macrophyllae Radix), and its type specimen was collected in Lijiang, Yunnan. There is a long planting history of the herb in this area. In this study a sampling plot was designated in these traditional planting areas. G. crassicaulis was planted and herbal raw materials were harvested from the plot. The raw materials were prepared locally and at a pharmaceutical factory in Shanghai using processing methods such as "sweating" or "no sweating", "slicing" or "no slicing" (whole root), and "stoving" or "no stoving" (air drying). The quality of all processed samples was evaluated. In addition, molecular markers were determined for identifying cultivated and wild samples from Lijiang, Yunnan. The results are as follows ① Samples from the sampling plot and the field are taxonomically identified as Gentiana crassicaulis. ② A total of 270 sequences of trnC-GCA-petN, atpB-rbcL, psbN, ndhB-rps7 and ycf1 were obtained, and three genotypes were determined from the cultivated samples; the type III was shared by both cultivated and wild plants. Based on the molecular markers, a DNA barcoding method to identify cultivated and wild samples of G. crassicaulis from Lijiang, Yunnan was established. ③ Total content of loganic acid and gentiopicroside in all samples was ≥ 2.5%, and above the Chinese Pharmacopoeia (2020) limit. ④ In HPLC fingerprinting, 9 common peaks were assigned and similarity between all samples was > 0.999; and ⑤ In a PCA score plot all slice samples were clustered, while whole root samples were scattered. Therefore, our studies could provide basic data for optimizing the processing method, producing best quality Gentianae Macrophyllae Radix, and evaluating the quality of different ecotype varieties and the multiple origin of herbal medicines.