Study on in vitro Antibacterial Effect of Extracts from Miao Medicine Rubus multibracteatus Leaves / 中国药房

ABSTRACT

OBJECTIVE:To investigate in vitro antibacterial effect of extracts from Miao medicine Rubus multibracteatus leaves. METHODS:The aqueous extract and 80% ethanol extracts from R. multibracteatus leaves were used to prepare solution with mass concentration of 200 mg/mL. Using ampicillin and fluconazol as positive control (50 mg/mL),cup plate method was used to determine antibacterial effects of the extracts from R. multibracteatus leaves to Staphylococcus aureus,Staphylococcus epi-dermidis,Escherichia coli,Shigella dysenteriae,Proteus vulgaris,Candida albicans and Cryptococcus neoformans. The petroleum ether,acetic ether and n-butyl alcohol were used to extract 80% ethanol extracts in turns. After obtaining relevant extracts (50 mg/mL),cup plate method was used to investigate antibacterial effects of them to above 7 bacterial strains. The parts with antibacte-rial effects and bacterial strains sensitive to drug were screened. Micro-broth dilution method and agar culture medium plate method were used to determine minimum inhibitory concentration(MIC)and minimum bactericidal concentration(MBC). RESULTS:The aqueous extract of R. multibracteatus leaves almost had no inhibitory effect while 80% ethanol extract showed different degrees of antibacterial effect to tested bacterial strains,and it also had higher activity against 5 bacterial stains than 2 fungus. The ethyl ace-tate and n-butyl alcohol fractions of 80% ethanol extracts showed good effect while the petroleum ether and water layer fractions had no antibacterial effect,and all the fractions of 80% ethanol extracts showed no inhibitory effect on fungus. To 5 bacterial stains,MIC and MBC of 80% ethanol extract were 6.25-12.5,12.5-25 mg/mL,those of ethyl acetate fractions were 3.13,6.25 mg/mL and those of n-butyl alcohol fraction were 3.13-6.25,6.25-12.5 mg/mL,respectively. CONCLUSIONS:80% ethanol ex-tract of Miao medicine R. multibracteatus leaves and its ethyl acetate and n-butyl alcohol fractions have obvious in vitro antibacteri-al effect to bacteria.