Comparative analysis of chemical composition, antioxidant and antimicrobial activities of leaves, leaf tea and root from Codonopsis pilosula

Abstract

Codonopsis pilosula is a perennial plant mainly used in medicines; for which only the roots are generally used, with the leaves going unused. To provide guidance for the comprehensive development and utilization of this plant, C. Pilosula leaves were processed into tea according to green tea processing technology. In this study, the chemical composition, antioxidant and antimicrobial activities of leaf tea (CLT), raw leaves (CL) and roots (CR) were studied and compared. The results showed that compared with CR, the total flavonoid, total polyphenol, protein and amino acids contents of CLT and CL were much higher. However, for the both water and ethanol extracts, the polysaccharide of CLT and CL were lower than that observed in CR. The chemical contents of CL and CLT were similar. Interestingly, with respect to lobetyolin, the primary medicinal component of C. pilosula, the level detected in CLT (0.68 mg/g) was much higher than that in CL (0.28 mg/g) and CR (0.23 mg/g). The results of DPPH, ABTS, FRAP analyses all indicated that the antioxidant activities of CLT and CL approached that of vitamin C (VC) at specific concentrations, whereas CR showed a much lower antioxidant capacity. Antimicrobial activity test showed that CLT and CL had antimicrobial activities against bacteria and yeast.In summary, compared with the most commonly used part of C. pilosula (the root), the leaves and leaf tea had a much stronger antioxidant activity and higher lobetyolin, protein, amino acid, polysaccharides, total flavonoid and total polyphenol levels. The leaves and tea also had antimicrobial activities against bacteria and yeast. Thus, C. pilosula leaves could actually be promising materials with economic prospects in many fields including for chemical extraction and as antioxidants in foods and cosmetics. Processing the leaves into tea allowed for higher levels of lobetyolin to be obtained but did not significantly decrease the chemical content, antioxidant and antimicrobial activities. Thus, C. Pilosula leaf tea could be used as a novel healthy product with high antioxidant activity, and high levels of nutrients and lobetyolin. Processing C. pilosula leaves into tea may be an appropriate and economic way of utilizing this plant reasonably.