Antimicrobial activities of the rhizome extract of Zingiber zerumbet Linn

Objective:To investigate antimicrobial effects of ethanolic extract of Zingiber zerumbet(Z.zerumbet)(L.)Smith and its chloroform and petroleum ether soluble fractions against pathogenic bacteria and fungi.Methods:The fresh rhizomes of Zingiber zerumbet were extracted in cold with ethanol(4.0 L)after concentration.The crude ethanol extract was fractionated by petroleum ether and chloroform to form a suspension of ethanol extract(15.0 g),petroleum ether fraction(6.6 g)and chloroform soluble fraction(5.0 g).The crude ethanol extract and its petroleum ether and chloroform fractions were evaluated for antibacterial and antifungal activity against thirteen pathogenic bacteria and three fungi by the disc diffusion method.Commercially available kanamycin(30μg/disc)was used as standard disc and blank discs impregnated with the respective solvents were used as negative control.Results:At a concentration of 400μg/disc,all the samples showed mild to moderate antibacterial and antifungal activity and produced the zone of inhibition ranging from 6 mm to 10 mm.Among the tested samples,the crude ethanol extract showed the highest activity against Vibrio parahemolyticus(V.parahemolyticus).The minimum inhibitory concentration(MIC)of the crude ethanol extract and its fractions were within the value of 128-256μg/mL against two Gram positive and four Gram negative bacteria and all the samples showed the lowest MIC value against V.parahemolyticus(128μg/mL).Conclusions:It can be concluded that,potent antibacterial and antifungal phytochemicals are present in ethanol extract of Z.zerumbet(L.).

Characterization and phylogenetic analysis of novel polyene type antimicrobial metabolite producing actinomycetes from marine sediments:Bay of Bengal India

Objective:To isolate and indentify the promising antimicrobial metabolite producing Streptomyces strains from marine sediment samples from Andraprudesh coast of India.Methods:Antagonistic aetinomycetes were isolated by starch casein agar medium and modified nutrient agar medium with 1%glucose used as a base for primary screening.Significant antimicrobial metabolite producing strains were selected and identified by using biochemical and 16S rDNA level.Minimum inhibitory concentrations of the organic extracts were done by using broth micro dilution method.Results:Among the 210 actinomyeetes,64.3%exhibited activity against Gram positive bacteria,48.5%showed activity towards Cram negative bacteria,38.8%exhibited both Cram positive and negative bacteria and 80.85%isolates revealed significant antifungal activity.However,five isolates AP-5,AP-18,AP-41 and AP-70 showed significant antimicrobial activity.The analysis of cell wall hydrolysates showed the presence of LL-diaminopimelic acid and glycine in all the isolates.Sequencing analysis indicated that the isolates shared 98.5%-99.8%sequence identity to the 16S rDNA gene sequences of the Streptomyces taxons.The antimicrobial substances were extracted using hexane and ethyl acetate from spent medium in which strains were cultivated at 30X for five days.The antimicrobial activity was assessed using broth micro dilution technique.Each of the culture extracts from these five strains showed a typical polyenelike property.The lowest minimum inhibitory concentrations of ethyl acetate extracts against Escherichia coli and Cumularia lunula were 67.5 and 125.0μg/mL,respectively.Conclusions:It can be concluded that hexane and ethyl acetate soluble extracellular products of novel isolates are effective against pathogenic bacteria and fungi.

Combined antibacterial activity of stingless bee(Apis mellipodae)honey and garlic(Allium sativum)extracts against standard and clinical pathogenic bacteria

Objective:To investigate the synergic antibacterial activity of garlic and tazma honey against standard and clinical pathogenic bacteria.Methods:Antimicrobial activity of tazma honey,garlic and mixture of them against pathogenic bacteria were determined.Chloramphenicol and water were used as positive and negative controls,respectively.Minimum inhibitory concentration(MIC)and minimum bactericidal concentration of antimicrobial samples were determined using standard methods.Results:Inhibition zone of mixture of garlic and tazma honey against all tested pathogens was significantly(P≤0.05)greater than garlic and tazma honey alone.The diameter zone of inhibition ranged from(18±1)to(35±1)mm for mixture of garlic and tazma honey,(12±1)to(20±1)nun for tazma honey and(14±1)to(22±1)mm for garlic as compared with(10±1)to(30±1)mm for chloramphenicol.The combination of garlic and tazma honey(30-35 mm)was more significantly(P≤0.05)effective against Salmonella(NCTC 8385),Staphylococcus aureus(ATCC 25923),Lyesria moncytogenes(ATCC 19116)and Streptococcus pneumonia(ATCC 63).Results also showed considerable antimicrobial activity of garlic and tazma honey.MIC of mixture of garlic and tazma honey at 6.25%against total test bacteria was 88.9%.MIC of mixture of garlic and tazma honey at6.25%against Gram positive and negative were 100%and 83.33%,respectively.The bactericidal activities of garlic,tazma honey,and mixture of garlic and tazma honey against all pathogenic bacteria at 6.25%concentration were 66.6%,55.6%and 55.6%,respectively.Conclusions:This finding strongly supports the claim of the local community to use the combination of tazma honey and garlic for the treatment of different pathogenic bacterial infections.Therefore,garlic in combination with tazma honey can serve as an alternative natural antimicrobial drug for the treatment of pathogenic bacterial infections.Further in vivo study is recommended to come up with a comprehensive conclusion.

Evaluation of anti-resistant activity of Auklandia(Saussurea lappa) root against some human pathogens

Objective:The antimicrobial activity of the ethanol extract of the Auklandia(Saussurea lappa)root plant was investigated to verify its medicinal use in the treatment of microbial infections.Methods:The antimicrobial activity of the ethanol extract was tested against clinical isolates ofsome multidrug-resistant bacteria using the agar well diffusion method.Commercial antibioticswere used as positive reference standards to determine the sensitivity of the clinical isolates.Results:The extracts showed significant inhibitory activity against clinical isolates of methicillinresistantStaphylococcus aureus,Pseudomonas aeruginosa,Escherichia coli,Klebsiella pneumonia,Extended Spectrum Beta-Lactemase,Acinetobacter baumannii.The minimum inhibitory concentration values obtained using the agar dilution test ranged from 2.0μg/μL-12.0μg/μL.In the contrary the water extract showed no activity at all against the tested isolates.Furthermore,theresults obtained by examining anti-resistant activity of the plant ethanolic extract showed thatat higher concentration of the plant extract(12μg)all tested bacteria isolates were inhibited with variable inhibition zones similar to those obtained when we applied lower extract concentrationusing the well diffusion assay.Conclusion:The results demonstrated that the crude ethanolicextract of the Auklandia(Saussurea lappa)root plant has a wide spectrum of activity suggestingthat it may be useful in the treatment of infections caused by the above clinical isolates(humanpathogens).

Antimicrobial activity of crude and semi-purified fractions of Warburgia ugandensis against some pathogens

Objective:To investigate in vitro antimicrobial activities of leaves and heartwood crude and semi-purified fractions of Warburgia ugandensis(Canellaceae)(W.ugandensis)on some pathogens.Methods:were prepared.Six bacteria[Klebsiella pneumoniae(K.pneumoniae),Escherichia coli(E.coli),Pseudomonas aeruginosa Crude and semi-purified fractions of the leaves and heartwood of W.ugandensis(P.aeruginosa),Shigella boydii(S.boydii),Staphylococcus aureus(S.aureus)and Streptococcus pneumonia]and one fungus(Candida albicans)were tested by agar well diffusion and broth dilution method to determine minimum inhibitory concentration(MIC).Results:S.boydii and S.aureus were found to be the most susceptible bacterial isolated in agar well diffusion and broth dilution method of both the crude and petroleum ether extracts,while K.pneumoniae was the most resistant bacterium isolated under the same condition except in chloroform fraction.K.pneumoniae had shown MIC value of 10 mg/mL in the leaves and heartwood in both the crude and petroleum ether extract.S.boydii and S.aureus had shown the MIC value of 1.0 mg/mL in the crude extract for the both leaves and heartwood;Whereas the petroleum ether semi-purified fraction had shown 0.5 mg/mL in the heartwood.In the crude extract,E.coli and P.aeruginosa exhibits similar MIC value of 1.75 mg/mL.In semi purified petroleum ether extract,E.coli had MIC value of 1.0 mg/mL;Whereas P.aeruginosa had shown no change in crude extract.Candida albicans revealed equal MIC value of 1.0 mg/mL for the both crude and semi-purified fractions of the leaves and heartwood.Conclusions:The crude and semi-purified fractions of W.ugandensis have considerable effect on pathogens.Semi-purified petroleum ether fraction has better antimicrobial activity in both agar well diffusion and broth dilution method.This study further shows the potential of W.ugandensis for further study in order to be use as a modern drug.

Antimicrobial activity of methanolic extracts of selected marine macroalgae against some pathogenic microorganisms

Objective:To evaluate the antimicrobial activity of methanolic extracts of six marine macroalgae belonging to green algae(Chlorophyceae),brown algae(Phaeophyceae)and the red algae(Rhodophyceae)collected from the intertidal area of the Sudanese Red Sea coast near Port Sudan.Methods:Methanol was used for extracting the active principles of the algae and the disc diffusion method was performed to examine the activity and the minimum inhibitory concentration of the samples against four pathogenic bacteria and two fungi.Results:All tested algal extracts exhibited considerable bioactivity and inhibited the growth of all pathogenic microorganisms under investigation.The green alga Caulerpa racemosa produced the maximum inhibition zone(21 mm)against Candida albicans while the red alga Laurencia papillosa showed low antimicrobial activity with the minimum inhibition zone of 10 mm against Pseudomonas aeruginosa.The tested algal extracts did not show any special antimicrobial influence on the selected microorganisms when they were considered as Grampositive and Gram-negative bacteria and fungi but the most efficient methanolic extracts in inhibiting microbial growth were those of green macroalgae followed by the brown and the red macroalgae respectively.Conclusions:The study demonstrated that the tested marine macroalgae from Sudanese Red Sea coast may represent a potential and alternative source for secondary metabolites with antimicrobial activity.

The antimicrobial activities of a series of bis-quaternary ammonium compounds

A series of bis-quaternary ammonium compounds（bis-QACs） N,N＇-hevamethylenebis（1-alkyl-4-carbamoyl pyridinium bromide）（4BCAP-6,n）（alkyl chain length,n=8,10,12,14,16 and 18） were synthesized and characterized.Their surface tensions,critical micelle concentrations（CMC）,and antimicrobial activities were evaluated.4BCAP-6,10 exhibited the strongest antimicrobial activities except for that against Proteus vulgari.The activities of 4BCAP-6.n against Escherichia coli zk126 were not significantly influenced by temperature.pH and initial bacteria concentration.These results indicate that bis-QACs exhibit high antimicrobial activity regardless of the environmental conditions.

Antimicrobial Agents from Selected Medicinal Plants in Libya

Objective： To test the in vitro antimicrobial efficacy of water and methanol extracts of 23 plant species that are commonly used in Libyan folk medicine. Methods： The antimicrobial activity was determined using the well-diffusion method. Four test microorganisms were used namely, Escherichia coil, Salmonella species, Staphylococcus aureus and Bacillus subtilis. The minimum inhibitory concentration （MIC） was determined for the high biologically active crude plant extracts. Results： Among 23 medicinal plants used in the study, only 5 methanolic extracts [Rosmarinus offcinalis L., Carduus marianium L., Lantana camara L., Rhus tripartite （ueria） Grande, and Thymus capitatus （L.） Hoffm （link）] showed the highest antimicrobial activity against Staphylococcus aureus, Bacillus subtilis and Salmonella species, while 22 methanolic and aqueous extracts showed moderate to weak antimicrobial activity on all tested organisms. However 19 of the extracts showed no activity at all against Gram -ve and Gram ＋ve microorganisms. MIC was found to be 1.25 mg/mL （Thymus capitatus）, 3 mg/mL （Rhus tripartite）, 4 mg/mL （Carduus marianium）, 5 mg/mL （Rosamarinus officinalis） and 5 mg/mL （Lantana camara）, respectively. Condusions： The present results revealed that, crude methanolic extracts of the investigated Libyan folk medicinal plants exhibited mild to high in vitro antibactedal activities against Gram-positive and Gram-negative microorganisms.

微生物源溶菌酶的抑菌及抗炎活性

为研究微生物源溶菌酶对14种供试菌的体外抑菌活性及对脂多糖(lipopolysaccharide,LPS)诱导的小鼠巨噬细胞RAW264.7细胞炎症的抑制作用,该文采用二倍稀释法测定微生物源溶菌酶对供试菌的最小抑菌浓度(minimum inhibitory concentration,MIC),评价其体外抑菌活性,通过构建LPS诱导的小鼠巨噬细胞RAW264.7炎症模型,以细胞中一氧化氮(nitric oxide,NO)及肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)的分泌量为指标,评价微生物源溶菌酶的抗炎活性。结果表明,微生物源溶菌酶对大肠杆菌、枯草芽孢杆菌、金黄色葡萄球菌、沙门氏菌、单增李斯特菌、耐热芽孢杆菌、酿酒酵母、酪丁酸梭菌、产黄青霉、黑曲霉和根霉11种菌均表现出良好的抑菌效果,具有较强的广谱抑菌性;在试验浓度范围内,对保加利亚乳杆菌、嗜热链球菌、乳酸乳球菌乳亚种3种益生菌无抑制效果,反而具有生长促进效果。微生物源溶菌酶对LPS诱导的小鼠巨噬细胞RAW264.7炎症模型表现出明显的抗炎作用,可显著降低NO及TNF-α的分泌,且与微生物源溶菌酶的作用浓度呈正相关。在试验浓度范围内,与模型组相比NO分泌量最高可降低57.92%,TNF-α分泌量最高可降低36.75%。微生物源溶菌酶具有良好的抑菌和抗炎活性,为其作为食品添加剂在抑制腐败菌生长、促进益生菌增殖等方面应用提供了理论基础。

一株类芽孢杆菌的鉴定及抗菌活性探究

为了筛选产新型天然抗菌物质微生物,本研究利用共培养的方法筛选目的菌株;通过16S rDNA、生理生化性质和全基因组测序鉴定菌株种属;利用抗菌物质稳定性、菌株基因组次级代谢产物预测和最小抑菌浓度研究抗菌物质的生物学特性。从土壤中筛选了一株类芽孢杆菌Paenibacillus elgii CL-1,该菌所产抗菌物质具有广谱抗菌性能,且耐受过氧化氢酶、胃蛋白酶、胰蛋白酶、蛋白酶K和酸碱,高温不稳定;利用antiSMASH分析发现Paenibacillus elgii CL-1含有penisin和octapeptin C4等17种次级代谢产物基因簇;进一步的分析发现,通过高效液相色谱从该菌发酵液中分离纯化出的抗菌物质抗菌谱广,抗菌活性好,最小抑菌浓度值可达1μg/mL。通过质谱分析发现类芽孢杆菌Paenibacillus elgii CL-1能够产生抗菌谱广、稳定性好和抗菌活性强的抗菌物质pelgipeptin B。本研究为挖掘天然抗菌药物pelgipeptin B提供底盘菌株,为其研发和应用奠定基础。

克林霉素原位富集土壤微生物群落多样性及抗菌活性分析

为了探究克林霉素原位富集土壤微生物多样性和优势菌群的抗菌活性,以克林霉素作为选择压进行原位富集,利用Illumina Navaseq高通量测序技术分析土壤微生物群落多样性;通过微生物培养技术结合滤纸片法以及菌饼对峙法,筛选出具有抗菌活性的耐药放线菌。结果表明,随着原位富集土壤中克林霉素添加量的增加,其物种丰度减少。在克林霉素质量浓度为1∶10和1∶100的原位富集土壤微生物中,主要优势菌目为微球菌目(Micrococcales)、弗兰科氏菌目(Frankiales)、棒状杆菌目(Corynebacteriales)、动孢菌目(Kineosporiales)、链霉菌目(Streptomycetales)。可培养水平上,克林霉素原位富集土壤中共分离出放线菌207株,分属于6目6科6属44种,其中链霉菌属(Streptomyces)为优势菌属,并筛选出25株对梨黑斑链格孢菌(Alternaria gaisen)具有较好抑制活性的放线菌。综上所述,添加克林霉素原位富集土壤微生物更有利于分离出对病原真菌产生拮抗的活性菌株,在病原菌生物防治中具有较大的应用前景。

黄精多糖抑菌及抗氧化性能研究

用滤纸片抑菌圈实验法研究了黄精多糖对常见的几种细菌的抑制作用。结果表明:黄精多糖对实验菌有明显的抑制作用。其中对金黄色葡萄球菌抑制作用最强,MIC=0.5%,抑菌圈直径为19.6mm,对大肠杆菌最弱,MIC=2.0%,抑菌圈直径为11.2mm。黄精多糖具有一定的抗氧化作用。

苦豆子生物碱抗菌活性的测定

采用抑菌圈法测定了槐定碱、苦参碱、氧化苦参碱、氧化槐果碱、苦豆子总碱对大肠杆菌、金黄色葡萄球菌、枯草芽孢杆菌、番茄早疫、番茄灰霉和辣椒炭疽的抗菌活性。试验结果表明,5种生物碱对3种细菌生长均具有显著的抑制作用,其中槐定碱和苦参碱对大肠杆菌、枯草芽孢杆菌和番茄早疫的抗菌效果明显优于其他3种生物碱,苦参碱对大肠杆菌和枯草芽孢杆菌的最小抑菌浓度(MIC)达到12.5μg/mL。5种生物碱对3种真菌的抗菌效果弱于对3种细菌的抗菌效果,5种生物碱对3种真菌的MIC大于等于100μg/mL,氧化苦参碱、氧化槐果碱和苦豆子总碱对番茄灰霉菌的MIC均达400μg/mL。在质量浓度为100μg/mL时,5种生物碱中仅槐定碱表现出对辣椒炭疽菌的抑制作用。苦豆子总碱抗菌活性影响因素的试验结果表明,苦豆子总碱具有良好的热稳定性,在弱碱性条件下(pH8左右)具有更好的抑菌活性,在至少12 h内能够持续、稳定的对供试菌产生抑制作用。

中草药提取物的体外抑菌活性研究

目的探讨10种中草药提取物的体外抗菌活性。方法制备10种中草药提取物,采用试管连续稀释法对金黄色葡萄球菌、大肠埃希菌、铜绿假单胞菌和白色念珠菌进行体外抑菌试验。结果10种中草药的提取物对金黄色葡萄球菌、大肠埃希菌、铜绿假单胞菌和白色念珠菌有不同程度的抑制活性;其中尤以赤芍、石榴皮、五味子和黄连的提取物抗耐药菌活性最高,赤芍提取物对上述4种菌的抑制活性均较高,其最低抑菌浓度(MIC)分别为7.80、1.95、1.957、.80 mg/ml。结论赤芍、石榴皮、五味子和黄连提取物呈现广谱抗菌特性,且具有抗耐药菌作用。

生姜挥发油抑菌活性研究

应用水蒸汽蒸馏法提取全姜挥发油、去皮姜挥发油和姜皮挥发油,通过体外抗菌实验,比较了这3种挥发油与常用食品防腐剂山梨酸钾对6种常见细菌和霉菌的抑菌活性。结果表明,3种挥发油对6种常见菌表现出不同的抑制活性,其抑制作用由强到弱依次为姜皮挥发油、全姜挥发油、去皮姜挥发油。3种挥发油的抑菌作用都强于相同浓度的山梨酸钾水溶液。由此可见,生姜挥发油在天然防腐剂开发方面具有广阔的应用前景。

20种中草药提取物的体外抗菌作用研究

目的测定20种云南中草药的80%乙醇提取物的体外抗菌活性。方法制备20种中草药的醇提物,用琼脂打孔法对其进行抗菌活性的筛选,通过微量稀释法测定其最低抑菌浓度(MIC)和最低杀菌浓度(MBC)。结果 20种中草药的醇提物中有7种对金黄色葡萄球菌(简称金葡菌)、大肠埃希菌、铜绿假单胞菌和白色念珠菌有不同程度的抑制活性;对标准金黄色葡萄球菌的抑菌圈大小在12～26 mm之间,耐甲氧西林金葡菌(methicillin-resistant Staphylococcus aureus,MRSA)抑菌活性在10～26 mm之间,MIC在16～>1 024 mg.L-1之间,MBC在512～>1 024 mg.L-1之间。另外牡丹根对铜绿假单胞菌有有较好的抑制作用,抑菌圈大小分别为17 mm和18 mm,其对铜绿假单胞菌的MIC/MBC为1 024/>2 048 mg.L-1。20种中草药对大肠埃希菌和白色念珠菌的抑制作用均较弱。结论马尾黄连、蜜桶花、石椒草、侧柏叶、田基黄、牡丹根、枇杷叶和胃友系具有强的抗MRSA活性的中草药,牡丹根对铜绿假单胞菌有较好的抑制作用。

两种兔耳草提取物的体外抑菌作用

短管兔耳草(Lagotis brevituba Maxim)和短穗兔耳草(Lagotis brachystachy Maxim)在传统藏药中具有抑菌消炎的功效。采用琼脂孔扩散法和96孔培养板对倍稀释法测定了这两种植物不同极性溶剂逐级提取物对4种采后真菌和4种腐败细菌的体外抑菌率和最低抑制浓度。结果表明:在供试真菌中,短管兔耳草提取物对F.semitectum和P.expansum具有抑菌活性,短穗兔耳草提取物对P.expansum和A.alternate具有抑菌活性。两种植物的提取物对供试细菌的抑菌活性整体上较强,短管兔耳草提取物对S.aureus和P.fluorescence有抑菌活性,而短穗兔耳草提取物对S.aureus,E.coli,B.subtilis和P.fluorescence都有抑菌活性。提取物对细菌的最低抑菌浓度最低可达0.05g/mL。结论:这两种植物的提取物具有较广的体外抑菌谱和较强的抑菌活性。

麝香草酚抑菌活性及其影响因素研究

采用滤纸片法和扩散法,研究不同浓度的麝香草酚对食品中常见10种污染菌的体外抑菌作用,并对其抑菌影响因素进行了研究。实验结果表明,麝香草酚对细菌、酵母和霉菌均有一定抑制作用。经测定,麝香草酚对金黄色葡萄球菌、枯草芽孢杆菌、大肠杆菌、变形杆菌、保加利亚乳杆菌、嗜热乳酸链球菌、异常汉逊氏酵母、酿酒酵母、黑曲霉、黄曲霉的最低抑菌浓度分别为10、20、20、40、40、40、80、40、80、160μg/mL。抑菌影响因素研究表明,吐温-80和有机氮(BSA)能明显消弱麝香草酚的抑菌能力;低pH则会明显增强麝香草酚的抑菌作用。

苍术挥发油的提取及其抑菌活性研究

采用水蒸气蒸馏法、微波萃取法和索氏提取法3种方法提取苍术挥发油。平板法涂布研究了3种苍术挥发油对3种细菌和4种真菌的最低抑菌浓度(MIC),滤纸片固相扩散法研究了苍术挥发油对供试菌体的抑菌活性。结果表明,3种方法提取的苍术挥发油对金黄色葡萄球菌、大肠杆菌、枯草芽孢杆菌、酵母、青霉、黑曲霉、黄曲霉的MIC分别为:水蒸气蒸馏法为5.00、150.00、150.00、5.00、5.00、5.00、20.00 mL/L;索氏提取法的为10.00、150.00、200.00、20.00、5.00、60.00、40.00 mL/L;微波萃取法的为10.00、150.00、150.00、20.00、20.00、20.00、20.00 mL/L。3种苍术挥发油对供试细菌和真菌都具有相当强的抑菌活性,且浓度越高效果越好。抑菌实验表明3种方法提取的苍术挥发油对金黄色葡萄球菌、酵母、青霉、黑曲霉、黄曲霉的抑菌圈直径都比对大肠杆菌、枯草芽孢杆菌的抑菌圈直径大。不同提取方法得到的苍术挥发油对同一种菌的最低抑制浓度和抑菌效果不相同,同一种方法提取的苍术挥发油对不同菌的最低抑制浓度和抑菌效果也不相同。

40种中药提取物对6种临床常见感染菌株的体外抑菌活性观察

目的观察苏木、地榆、淫羊藿、黄连、白芍等40种贵州省常见中药对6种临床常见感染菌株的体外抑菌活性。方法取40种中药(厚朴、陈皮、益母草、连翘、三七、虎杖、百部、菌陈、拳参、半夏、龙胆草、玄参、黄精、苦瓜、天冬、瓜蒌、淫羊藿、木蝴蝶、木香、姜黄、杜仲、白芨、木瓜、白头翁、地榆、苏木、白芍、紫草、山豆根、钩藤、黄药子、猪牙皂、黄柏、女贞子、山慈菇、黄连、石斛、栀子、枳壳、金钱草)制备水提取液或乙醇提取液。采用纸片琼脂扩散法(K-B法)测算40种中药提取物对6种标准菌株(金黄色葡萄球菌、铜绿假单胞菌、大肠埃希菌、鲍曼不动杆菌、粪肠球菌、肺炎链球菌)的抑菌圈直径。筛选出对标准菌株有抑菌作用(抑菌圈直径范围10~21 mm)的中药提取物,采用微量肉汤稀释法测定中药提取物对6种标准菌株及其临床分离耐药菌株的最小抑菌浓度(MIC)值。结果K-B法显示15种中药提取物(三七、虎杖、半夏、龙胆草、玄参、黄精、瓜蒌、淫羊藿、木香、地榆、苏木、白芍、紫草、猪牙皂、黄连)对至少1种标准菌株有抑菌作用,抑菌圈直径为10~21 mm;黄连对肺炎链球菌、苏木对金黄色葡萄球菌的抑菌效果较好,抑菌圈直径分别为21、20 mm。15种中药MIC在15.63~1 000 mg/m L,其中黄连对肺炎链球菌、苏木对金黄色葡萄球菌的MIC值均为15.63 mg/m L,淫羊藿对肺炎链球菌、地榆对肺炎链球菌的MIC值均为31.25 mg/m L。筛选出5种抑菌活性较强的中药为苏木、地榆、淫羊藿、黄连、白芍,对6种临床分离的耐药菌株有不同程度的抑菌效果,其中苏木对耐甲氧西林金黄色葡萄球菌、黄连对产超广谱-β内酰胺酶肺炎链球菌的MIC_(50)均为15.63 mg/m L。结论 40种中药中苏木、地榆、淫羊藿、黄连、白芍对临床常见感染菌株的抑菌活性较好,黄连对肺炎链球菌及苏木对金黄色葡萄球菌的抑菌作用最强,苏木对铜绿假单胞菌和白芍、地榆对鲍曼不动杆菌也有一定抑菌效果。