In vitro Antibacterial Activities Extracts from Four Plants Used as Traditional Chinese Medicine Guanzhong

The water extracts(PWE)and the alcohol extracts(PAE)from rhizome of Brainea insignis,Osmunda vachellii,Woodwardia japonica and Blechnum orientale were prepared respectively.The inhibition zone,minimal inhibitory concentration(MIC)and minimal bactericidal concentration(MBC)of extracts to 11 kinds of common pathogenic bacteria were determined by disk diffusion method and tube double dilution method.The results showed that the PWE and the PAE of all those plants(1 g crude drug/mL)had obviously inhibitory effect on four Gram-positive bacteria,Staphylococcus epidermidis,Bacillus subtilis,Staphlococcus aureus,and Listeria monocytogenes,especially on Staphylococcus epidermidis,and the antibacterial activities of alcohol extracts were higher than those of water extracts,but had no inhibitory effect on Gram-negative bacteria. Among the four original Guangzong plants,the extracts of Brainea insignis showed the highest inhibitory effect on Gram-positive bacteria.