Molecular Identification and Targeted Quantitative Analysis of Medicinal Materials from Uncaria Species by DNA Barcoding and LC-MS/MS.

Shugen Wei,Jine Fu,Lixia Zhang,Xiaojun Ma,Zhonglian Zhang,Jing Qiao,Zuliang Luo,Shengrong Cui

doi:10.3390/molecules24010175

Abstract

The genus Uncaria is an important source of traditional Chinese medicines with multiple therapeutic effects. The identification of the correct species and accurate determination of the contents of bioactive constituents are important for quality control of Uncaria medicinal materials. Here, an integrated evaluation system based on DNA barcoding for species identification and quantitative analysis by LC-MS/MS has been established. DNA barcoding based on the ITS2 barcode region showed sufficient discriminatory power to precisely identify 24 samples from seven Uncaria species. The length of the 24 ITS2 sequences of Uncaria samples is 227 bp, and 17 variation sites were detected. Additionally, the results of qualitative and quantitative chemical analyses by LC-MS/MS indicated that the chemical compositions of all Uncaria samples were similar; while their contents of targeted alkaloids in samples from different species and origin areas were different. The contents of rhynchophylline (RC) and isorhynchophylline (IRC) were 2.9–1612 mg/kg and 2.60–1299 mg/kg in all tested samples, respectively. This study concludes that DNA barcoding should be used as the first screening step for Uncaria medicinal materials. Then, integration of DNA barcoding with chemical analyses should be applied in quality control of Uncaria medicinal materials in the medicinal industry.

Highlights

The pantropical plant genus Uncaria contains about 34 species
Our results suggest that DNA barcoding could be used as a screening step during the herbal medicine manufacturing process, and further quantitative analysis is important for improving the quality of Uncariae Ramulus Cum Uncis (URCU)
There were 17 variable sites in the ITS2 sequences that were segregated into nine sequence haplotypes (H): H1 (UHI1), H2 (UHO1), H3 (UMA1, UMA3), H4 (UMA2), H5 (URH1-4 and URH6-15), H6 (URH5), H7 (USC1), H8 (USE1) and H9 (USI1 and Uncaria sinensis (USI) 2) (Table 1)

Summary

Introduction

The pantropical plant genus Uncaria contains about 34 species. The majority are widely used as traditional medicines worldwide for the treatment of fevers, headaches, gastrointestinal illness, hypertension, epilepsy, wounds and ulcers, etc. Uncariae Ramulus Cum Uncis (URCU), the dried hook-bearing branches of five plants—Uncaria rhynchophylla (URH), Uncaria hirsute (UHI), Uncaria macrophylla (UMA), Uncaria sinensis (USI) and Uncaria sessilifructus (USE)—is a well-known herbal medicine mentioned in Chinese Pharmacopoeias [4]. In the Japanese pharmacopoeias, URCU was defined as hook or the hook-bearing stem of three plants: URH, UMA, and USI [5]. The phytopharmaceuticals that contain Uncaria plants, such as Tian-ma-gou-teng Granules, Diao-teng-san (Cho-Deung-Sanin Korean and Choto-san in Japanese) and Yi-Gan san (Yokukansan in Japanese) have become best-selling herbal medicines for the treatment of strokes, hypertension, chronic headaches and dizziness in China, Korea

Methods

Results

Discussion

Conclusion