Study On Antibacterial Activity Of Extractive And Active Constituent Of Glycyrrhizae

At present, there are many different kinds of antimicrobial drugs, but as the abuse of antibacterial agents leading to many drug-resistant bacteria emerging. So, looking for new natural antibacterial drugs becomes the research focus in the current.Glycyrrhiza uralensis Fisch. belongs to the Glycyrrhiza, family of Leguminosaesp. It has rich resources in China. It is a kind of Chinese tonic herbal medicine that folk commonly used. In recent years, the researchers isolated variety of terpenoids, flavonoids and other compounds from glycyrrhiza. Although some literature about glycyrrhiza has reported some antimicrobial activity compounds, but there is few reports about antibacterial activity monomer of glycyrrhiza. In order to make the best use of licorice, finding new monomer compounds which possess antibacterial activity, the glycyrrhiza used in this experiment was obtained from Inner Mongolia.Streptococcus mutans, Staphylococcus aureus, Methicillin-resistant staphylococcus aureus, Quinolone resistant staphylococcus aureus, Bacillus subtilis and Escherichia coli was used for the model, observation antimicrobial activity of glycyrrhiza extracts. The result shows that it has good bacteriostatic action. On the basis of this research, the ethanol extract of alcohol refluxing and methanol extract of methanol quenching were extracted with petroleum ether and ethyl acetate. The extract of different parts were tested for their antibacterial activity, the result show that the active fractions of glycyrrhiza on anti-bacterial effect were fractions of petroleum ether and ethyl acetate extract, in particular ethyl acetate.Some compounds were isolated from the active fractions by silica gel chromatography, six monomer compounds were isolated from fractions of ethyl acetate. The structures of four compounds were identified as oleicacid (Ⅰ), dehydroglyasperin D (II), Glycyrrhetinic acid (Ⅲ), Liquiritin (Ⅳ) by spectroscopic methods (1H-NMR,13C-NMR, DEPT, HMBC,1H-1H COSY, TOF-MS, etc.) and chemical means. Compound Ⅰ, Ⅱ and Ⅲ possess good antimicrobial activity against Streptococcus mutans, Staphylococcus aureus, Methicillin-resistant staphylococcus aureus, Quinolone resistant staphylococcus aureus and Bacillus subtilis, the MIC value was16～32μg/mL,8～16μg/mL and32～64μg/mL, respectively.This study not only improves the understanding about chemical compounds and antibacterial activity of glycyrrhiza, but also provides scientific evidence for further research and develop glycyrrhiza.