ABSTRACT
OBJECTIVE: To establish an accurate and rapid method for identifying Mesona chinensis and its adulterants using the internal transcribed spacer 2 (ITS2) region as a barcode. METHODS: The total genomic DNA from 55 samples representing five species and four variants including M. chinensis and its adulterants were extracted. The ITS2 regions were amplified, and the complete ITS2 sequences were annotated by CodonCode Aligner. The intra- and inter-specific genetic distances based on Kimura 2-Parameter (K2P) and the Neighbor-Joining (NJ) phylogenetic tree were analyzed to identify the species. RESULTS: The lengths of all the 1TS2 sequences of M. chinensis were 232 bp. The intra-specific genetic distances (0) were far shorter than the inter-specific ones between M. chinensis and its adulterants (0.210 2-0.301 9). NJ tree analysis indicated that M. chinensis were accurately differentiated from its adulterants. CONCLUSION: The ITS2 region as an DNA barcode can accurately and effectively distinguish herbal tea ingredient M. chinensis from its adulterants, which provides a quick identifying method to ensure its safe use.
ABSTRACT
Objective:To develop a method for the determination of natural benzoic acid in Mesona chinensis Benth. with different production places and storage time. Methods:HPLC was adopted, the column was an Agilent ZORBAX SB-C18 (250 mm × 4. 6 mm, 5 μm) column, the mobile phase was methanol-0. 02 mol·L-1 ammonium acetate (5∶95) at the flow rate of 1. 0 ml·min-1 , the col-umn temperature was 35℃, the detection wavelength was 230 nm, and the injection vocume was 10μl. Results:Benzoic acid showed good linearity over the concentration range of 0. 1-10. 0 μg·ml-1(r=0. 999 9). The average recovery was 99. 59%(RSD=1. 57%, n=9). Natural benzoic acid in powered Mesona chinensis Benth. was different because of various production places. The maximum content of natural benzoic acid in Mesona chinensis Benth. was 141. 8 mg·kg-1, while the minimum content was 73. 8 mg·kg-1. The content of natural benzoic acid in Mesona chinensis Benth. stored for two years was declined obviously. Conclusion: The method with simple operation is accurate and reproducible. It can provide a basis for the further study of Mesona chinensis Benth. resources, and provide a reference for the content determination of natural benzoic acid in other plants.