A comparative study using chemometric and numerical taxonomic approaches in the identification and classification of traditional Chinese medicines of the genus Clematis

Abstract

A comparative study was performed to identify and classify traditional Chinese medicines (TCMs) of the genus Clematis by applying chemometric and numerical methodologies. In the analysis, 12 species representing major TCM plants of the genus and belonging to five different sections – Rectae, Clematis, Meclatis, Tubulosae and Viorna – were identified and demarcated on the basis of morphological and phytochemical characters. In the numerical study (NS), out of 53 selected characters, only 27 phylogenetically informative characters were used for data generation; a phenogram was produced with three distinctive clades. The extent of genetic distances ranged from 0.35 to 0.80. The phytochemical analysis (PA) was conducted using a high performance liquid chromatography coupled with a diode array detector (DAD) and ESI‐MS mode. The compound “Huzhangoside D” (HGD) was the most abundant in the analysed species of the genus. The PA of saponins produced a differential matrix based on the presence or absence of chemical characters, which generated a phenogram. The extent of genetic distances ranged from 0.05 to 0.35 in the phytochemical analysis, with three distinctive clades. Clematis intricata had compounds (HGB, HGD) with GD 0.30, and produced a different pattern of clustering than the previous classification system. The species C. henryi and C. heracleifolia appeared as sister clades having congruent genetic similarity with each other; this is an innovative combination. The classification results of PA and NS approaches corroborate each other, but the chemical fingerprinting method proved more authentic, quick and reliable for the identification and classification of these plant taxa.

Keywords:

• Chemotaxonomy
• Clematis
• HPLC fingerprints
• Huzhangoside D
• LC‐ESI‐MS
• numerical taxonomy
• Ranunculaceae
• saponins
• traditional Chinese medicines

Acknowledgements

The authors wish to thank the staff members of the Tian Mu Shan Biosphere Reserve, who helped in the collection of plant specimens. Special thanks to Professor J.H. Chen, who provided considerable help during the field trips and for the identification of specimens. Other members of the laboratory who helped, directly or indirectly, in this research are gratefully acknowledged.