Study on the antibacterial activity of extracts from wild Arctum lappa L. root.

[Objective]To study the antibacterial activity of different solvent extracts from wild Arctum lappa L.roots,so as to provide theoretical basis for its development and utilization.[Method]The method of minimum inhibitory concentration(MIC) and agar-well diffusion were adopted to determine the inhibitory activity of water and 70% ethanol extracts from burdock roots.[Result]Both extracts revealed the potential inhibitory activities against Escherichia coli,Proteus vulgaris,Bacillus subtilis and Staphylococcus aureus.A higher antimicrobial activity was observed in 70% ethanol extracts compared with water extracts,and the MIC to Bacillus subtilis and Staphylococcus aureus was 31.25 mg/ml,the MIC to Proteus vulgaris was 62.50 mg/ml,while that to Escherichia coli was 250 mg/ml;nevertheless,neither water extracts nor 70% ethanol extracts showed obvious antimicrobial effects on Saccharomyces erevisiae and Monilia albican.[Conclusion]The water and 70% ethanol extracts from Arctum lappa L.roots are endowed with good inhibitory effects on bacteria instead of yeasts,and 70% ethanol extracts are provided with better antimicrobial activity than water extracts.