苗药大乌泡叶提取物的体外抑菌作用考察

摘要

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.%目的:考察苗药大乌泡叶提取物的体外抑菌作用.方法:将大乌泡叶煎煮水提物和80%醇提物均制备成质量浓度为200 mg/mL的药液,并以氨苄青霉素和氟康唑为阳性对照(50 mg/mL),采用管碟法测定其对金黄色葡萄球菌、表皮葡萄球菌、大肠埃希菌、痢疾志贺菌、普通变形杆菌、白色念珠菌、新型隐球菌的抑菌作用.依次用石油醚、乙酸乙酯、正丁醇萃取80%醇提物,得到相应部位萃取物(50 mg/mL)后,采用管碟法考察其对上述7种菌株的抑菌作用;筛选出具有抑菌作用的部位及对药物敏感的试验菌株,并分别采用微量肉汤稀释法和琼脂培养基平板法测定其最低抑菌浓度(MIC)和最低杀菌浓度(MBC).结果:大乌泡叶的水提物几乎无抑菌活性,80%醇提物对各菌株则表现出不同程度的抑制作用,对5种细菌的抑菌作用优于对2种真菌;大乌泡叶80%醇提物的乙酸乙酯及正丁醇萃取部位表现出良好的抑菌作用,石油醚和水层部位几乎没有抑菌作用,各萃取部位对真菌均未见抑制作用;大乌泡叶80%醇提物对5种细菌的MIC、MBC分别在6.25~12.5、12.5~25 mg/mL之间,其乙酸乙酯部位的MIC、MBC分别为3.13、6.25 mg/mL,其正丁醇部位的MIC、MBC分别在3.13~6.25、6.25~12.5 mg/mL之间.结论:苗药大乌泡叶的80%醇提物及其乙酸乙酯、正丁醇萃取部位对细菌具有明显的体外抑菌作用.