A Taxonomic Study Of The Genus Stephania Lour. From China

The genus Stephania Lour., belonging to the tribe Menispermeae (Menispermaceae), contains about 60 species worldwide. There are 39 species and one variant distributed in China, and many of them are commonly used for medical purpose. However, some medicinal species of Stephania are overexploited, and the subdivision of this genus remains controversial. Therefore, the present study is to investigate Stephania plant resources, and to study the molecular systematics and chemotaxonomic relationship within the genus. The results provide valuable data for the development and utilization of Stephania plants.1. Resource investigation and plants identificationWe conducted field surveys in seven provinces (Guangxi, Guangdong, Yunnan, Sichuan, Zhejiang, Jiangsu and Chongqing), and have collected 53 plant samples from 30 Stephania species, which cover each subgenus and section in the genus Stephania. The investigation provides adequate samples for the subsequent taxonomic research and a preliminary understanding of the current medicinal plant resources of Stephania.2. Molecular systematics of the genus StephaniaThe phylogenetic trees were constructed with the ITS and trnL-F sequences from species of genus Stephania native to China. The genus is well divided into three subgenera, which is consistent with traditional classifications based on morphological characters. However, it is difficult to divide the Stephania subgenera into different sections, suggesting that the sections based on previous classifications are not monophyletic. S. excentrica Lo, the position of which is controversial, joins to the subgenus Tuberiphania in the phylogenetic trees.3. Qualitative analysis and distribution of alkaloidsAn MAE-HPLC method was developed and validated for the qualitative analysis of alkaloids in Stephania plants, and the experimental data were analyzed by principal component analysis (PCA). Three subgenera in the genus Stephania can be differentiated by chemical characteristics. However, it is difficult to distinguish different sections within the Stephania subgenera. S. excentrica Lo is distributed to the cluster of the subgenus Tuberiphania in the PCA score plot.4. Discussion on taxonomic relationship within the genus StephaniaAccording to the results of molecular phylogeny and chemical analysis, the division of three subgenera in the genus Stephania is reasonable, but it is difficult to subdivide the subgenera into different sections. S. excentrica Lo should be positioned in the subgenus Tuberiphania. The present study provided valuable information on the phylogenetic relationships among the species of genus Stephania in China.