Abstract: The ethanolic extracts from licorice (Glycyrrhiza uralensis Fisch.) roots were examined for antimicrobial activity against five bacteria (Staphylococcus epidermidis, Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa) and two fungi (Candida albicans, Aspergillus nigar) by using disc diffusion method and broth micro dilution method. Results showed, ethanolic extracts from the licorice roots exhibited high susceptivity against gram-positive bacteria, while no sensitivity against gram-negative bacteria and fungi. The range of MIC of 10% ethanolic extract against gram-positive bacteria is 0.156~0.312 mg·mL^-1, while that of 80% ethanolic extract is 0.625~1.250 mg·mL^-1.The results indicated that antibacterially active components of licorice roots can dissolved in higher concentration ethanol more easily, which provides scientific basis for the application of ethanolic extracts from the licorice roots as antibacterial preparation in clinic.

Key words: licorice, roots, ethanolic extracts, antimicrobial activity