首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 250 毫秒
1.
Under controlled conditions, extracts of garlic, onion, turnip, green peppers and radishes were used to inhibit Escherichia coli, Salmonella typhosa, Shigella dysentriae and Staphylococcus aureus, which are all pathogenic bacteria. It was found that 1–4% by vol. of garlic extract completely inhibited the growth of all the bacteria used. 4% by vol. of onion extract completely inhibited the growth of both Shigella dysentriae and Staphylococcus aureus at 10–6 dilution. Salmonella typhosa and E. coli were not completely inhibited; the inhibition was 48·3% for E. coli and 95·3% for Salmonella typhosa. At 10–4 bacterial dilution, onion extract decreased the colony number substantially in all four bacteria. 4% extracts from turnip, green peppers and radishes did not show a definite antibacterial action against any bacterium at the given dilutions. On the contrary some growth stimulating activity of these extracts on some bacteria was observed.  相似文献   

2.
Twenty-two edible plant extracts were subjected to evaluation of their antibacterial activity against some gastrointestinal pathogenic bacteria, including Escherichiacoli, Salmonella typhimurium, Salmonella typhi, Shigella sonnei and Helicobacter pylori using the disc diffusion and broth microdilution methods. Sixteen of the plant extracts exhibited antibacterial activity against one or more tested bacteria. Only Garcinia cowa leaf extracts exhibited antibacterial activity against all tested bacteria. Purification of the ethyl acetate extract of G. cowa leaves using an antimicrobial assay-guided isolation afforded a new polyprenylated benzophenone, chamuangone, that exhibited satisfactory antibacterial activity against Streptococcus pyogenes (minimum inhibitory concentration (MIC) 7.8 μg/ml), Streptococcus viridans and H. pylori (MICs 15.6 μg/ml), and Staphylococcus aureus, Bacillus subtilis and Enterococcus sp. (MICs 31.2 μg/ml).  相似文献   

3.
Ether, methanolic and aqueous extracts of lyophilized rambutan (Nephelium lappaceum L.) peels and seeds were evaluated for phenolic contents, antioxidant and antibacterial activities. High amounts of phenolic compounds were found in the peel extracts and the highest content was in the methanolic fraction (542.2 mg/g dry extract). Several potential antioxidant activities, including reducing power, β-carotene bleaching, linoleic peroxidation and free radical scavenging activity, were evaluated. The peel extracts exhibited higher antioxidant activity than the seed extracts in all methods determined (P < 0.05). The methanolic fraction was found to be the most active antioxidant as shown by their 50% DPPH inhibition concentration, 4.94 μg/mL. The results indicated this fraction exhibited greater DPPH radical scavenging activity than BHT and ascorbic acid (0.32 g dry extract/g BHT or ascorbic acid). Antibacterial activity against eight bacterial strains was assessed by disc diffusion and broth macrodilution methods. All peel extracts exhibited antibacterial activity against five pathogenic bacteria. The most sensitive strain, Staphylococcus epidermidis, was inhibited by the methanolic extract (MIC 2.0 mg/mL).  相似文献   

4.
The objective of this study was to investigate prebiotic potential, chemical composition, and antioxidant capacity of spice extracts. Seven culinary spices including black pepper, cayenne pepper, cinnamon, ginger, Mediterranean oregano, rosemary, and turmeric were extracted with boiling water. Major chemical constituents were characterized by RP‐HPLC‐DAD method and antioxidant capacity was determined by measuring colorimetrically the extent to scavenge ABTS radical cations. Effects of spice extracts on the viability of 88 anaerobic and facultative isolates from intestinal microbiota were determined by using Brucella agar plates containing serial dilutions of extracts. A total of 14 phenolic compounds, a piperine, cinnamic acid, and cinnamaldehyde were identified and quantitated. Spice extracts exhibited high antioxidant capacity that correlated with the total amount of major chemicals. All spice extracts, with the exception of turmeric, enhanced the growth of Bifidobacterium spp. and Lactobacillus spp. All spices exhibited inhibitory activity against selected Ruminococcus species. Cinnamon, oregano, and rosemary were active against selected Fusobacterium strains and cinnamon, rosemary, and turmeric were active against selected Clostridium spp. Some spices displayed prebiotic‐like activity by promoting the growth of beneficial bacteria and suppressing the growth of pathogenic bacteria, suggesting their potential role in the regulation of intestinal microbiota and the enhancement of gastrointestinal health. The identification and quantification of spice‐specific phytochemicals provided insight into the potential influence of these chemicals on the gut microbial communities and activities. Future research on the connections between spice‐induced changes in gut microbiota and host metabolism and disease preventive effect in animal models and humans is needed.  相似文献   

5.
The aqueous and ethanol extract of Calotropis procera leaf and latex were investigated. The leaves and latex from the plant were tested for antimicrobial activities. The bioactive constituents extracted from the leaf and latex were tested against pathogenic organisms (Eschericia coli, Salmonella typhi, Bacillius subtilis, Candida albicans, Aspergillus niger) using the Agar well diffusion method. The ethanolic latex extract showed significant activity against all the test organisms. The results revealed that ethanol is a more effective extractive solvent for antimicrobial activity of leaf and latex of C. procera. The ethanol extract of the latex gave the widest zone of inhibition (21 mm) against B. subtilis. All the extracts inhibit the growth of all the organisms except B. subtilis of which the aqueous extract has no effect. The Minimum Inhibitory Concentration (MIC) for the latex extract was between 3 and 7.5 mg/ml for bacteria, and 5.0 to 7.0 mg/ ml for fungi. For the leaf extract the MIC for bacteria was between 5.0 and 10.5 mg/ml and 11 and 15 mg/ml for fungi. The results also showed an increase in antimicrobial activity with increase in temperature. This study therefore revealed that C. procera latex extract demonstrated strong and better inhibitory activity on the test organisms than the leaf extract. These findings therefore provide an explanation for the traditional medicinal use of C. procera extracts.  相似文献   

6.
In the study, antibacterial activities of the seed extracts of three different grapes were examined against fifteen bacteria, and total phenolic contents of the extracts were additionally determined. The contents of total phenolic compounds of the grape seed extracts were 589.09 (Hasandede), 506.60 (Emir) and 549.54 (Kalecik Karasi) mg gallic acid equivalent (GAE) per gram with acetone:water:acetic acid (90:9.5:0.5). These extracts at 1%, 2.5%, 5% and 10% concentrations were tested for their antibacterial effects by using the agar diffusion method against some pathogenic and spoilage bacteria including Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Enterococcus faecalis, Escherichia coli, E. coli O157:H7, Klebsiella pneumoniae, Mycobacterium smegmatis, Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas fluorescens, Salmonella enteritidis, Salmonella typhimurium, Staphylococcus aureus and Yersinia enterocolitica. All tested bacteria were inhibited by the grape seed extracts using agar well diffusion method. The most sensitive of the bacteria was A. hydrophila while Hasandede grape seed extract was the most inhibitive extract on test bacteria. Hasandede seed extract at 10% concentration gave the largest inhibition zone diameter (30.67 mm) against A. hydrophila. According to serial dilution method, while all the grape seed extracts at 0.5% and 1% concentrations had generally bacteriostatic activities against E. coli O157:H7, the same extracts appeared to have bactericidal effects at concentrations above 2.5%. In addition, the extracts at all concentrations had bactericidal activities against S. aureus at the end of 48 h. and A. hydrophila at the end of 1 h.  相似文献   

7.
《International Dairy Journal》2006,16(9):1049-1057
Several Bifidobacterium strains, including commercial probiotics, were screened for the production of antibacterial substances active towards Gram-negative pathogenic bacteria. Agar spot assays, microtitre plate assays, and time-kill studies were performed. Bifidobacteria were found to exert strong inhibitory activity towards Gram-negative indicator bacteria, namely Salmonella enterica serovar Typhimurium SL1344 and Escherichia coli C1845. The inhibitory mechanism was investigated and was shown to be dependent on the lowering of the pH of the medium and the production of organic acids, in particular acetic acid and lactic acid. The production of other antibacterial substances was examined by concentrating the cell-free culture supernatants by ammonium sulphate precipitation and chloroform/methanol extraction. The extracts of cultures of seven Bifidobacterium strains inhibited the growth of Gram-positive indicator bacteria, indicating that they produced a bacteriocin. The extract of a culture of Bifidobacterium longum BB536 was active against E. coli as well. However, the contribution of such inhibitory substances to the antibacterial activity of bifidobacteria towards Gram-negative pathogenic bacteria was found to be negligible.  相似文献   

8.
The antibacterial activity of ethanol extracts of Eugenia jambolana L. and E. uniflora L. (Myrtaceae) were evaluated by agar-well diffusion method and MICs by microdillution method. E. jambolana showed antibacterial activity against MRSA strains (MIC < 1024 μg/mL). E. uniflora did not show significant antibacterial activity (MIC > 1024 μg/mL). It is therefore suggested that extracts from E. jambolana could be used as an anti– Staphylococcus agent. When compared with Methicillin and Gentamicin, the extract was more effective against, being a promising antibacterial agent. Based on the author's knowledge, this is the first report about the antibacterial activity of leave ethanol extract from Eugenia jambolana.  相似文献   

9.
Ethanol and chloroform extracts of pumpkin, quince, muskmelon, and bottle gourd seeds were studied for in-vitro antioxidant and antibacterial activities. Crude protein and fat contents of all the seeds compared favorably with high protein legumes and high oil containing oilseeds. Ethanol and chloroform extracts of bottle gourd seeds had highest phenolic content. A direct positive relationship between antioxidant activities and extract concentration was observed with the relationship being more pronounced in chloroform extract of quince seeds (R2?=?0.9685 and 0.9829) followed by ethanol extract of pumpkin seeds (R2?=?0.9666 and 0.9685) as per 1,1-diphenyl-2-picrylhydrazyl and hydrogen peroxide (H2O2) method, respectively. Seed extracts were also studied for in-vitro antibacterial activity against Salmonella typhii, Enterococcus sp., Escherichia coli, Bacillus subtilis and Staphylococcus aureus. Ethanol extract of pumpkin seeds inhibited the growth of all bacteria; however, both the extracts of quince seeds did not show any activity against S. typhii, E. coli and S. aureus.  相似文献   

10.
Chloroformic extracts of selected Thai medicinal plants commonly employed to treat infections were investigated for their antibacterial activity against important foodborne pathogenic bacteria. These included Bacillus cereus, Staphylococcus aureus, methicillin‐resistant S. aureus (MRSA), Escherichia coli O157:H7, Salmonella Typhi and Shigella sp. Among 33 extracts tested, only chloroformic extracts of five plant species exhibited antibacterial properties. Alpinia galanga, Boesenbergia rotunda, Zingiber zerumbet and Piper betel were active against S. aureus. Barleria lupulina was active against B. cereus. Only the extract from P. betel leaves possessed activity against gram‐negative bacteria. As extracts from the three plant species belonging to family Zingiberaceae displayed strong activity against S. aureus, they were further tested against 17 clinical isolates. Minimum inhibitory concentration (MIC) values of B. rotunda, A. galanga and Z. zerumbet extracts against most clinical S. aureus isolates were 0.01, 0.19 and 0.79 mg/mL and the minimum bactericidal concentration (MBC) values were 0.19, 1.57 and >12.5 mg/mL, respectively. Significant growth inhibition of MRSA was observed in the cultures incubated in the presence of the B. rotunda extract, A. galanga and Z. zerumbet. B. rotunda exhibited the greatest activity among the three plant species against S. aureus at MIC, 2MIC and MBC within 2 h.  相似文献   

11.
以4种食品腐败菌为指示菌,采用滤纸片法和液体倍比稀释法对裸燕麦(Avena nuda L.)种子萌发过程中不同溶剂提取物的抑菌作用和最低抑菌浓度(MIC)进行了比较研究。试验结果表明,乙酸乙酯提取物的抑菌作用较好,但在种子萌发过程中抑菌效果不同,萌发24 h时燕麦种子的乙酸乙酯提取物的抑菌作用最强,其中对大肠杆菌的抑菌圈直径达(22.31±0.05)mm;其对金黄色葡萄球菌和大肠杆菌的最低抑菌浓度MIC小于6.25%,对鼠伤寒沙门氏菌和肠炎沙门氏菌的最低抑菌浓度MIC小于12.5%,旨为燕麦的综合利用及新型天然防腐剂的研发提供理论依据。  相似文献   

12.
目的 探究乳酸菌HS011(LactobacillusplantarumMG5276)、德氏乳杆菌保加利亚亚种HS023(Lactobacillus delbrueckii subsp. Bulgaricus strain NDO4)、嗜热链球菌HS033 (Streptococcus thermophilus 3233)对耐甲氧西林金黄色葡萄球菌(methicillin-resistant Staphylococcus aureus, MRSA)的抑菌机制。方法 以MRSA为研究对象,探索乳酸菌粗提物对MRSA菌株的最小抑菌浓度(minimum inhibitory concentration, MIC)的影响、抗菌药物复合作用对细菌生长的影响、抽提物对MRSA生物被膜抑制和清除效果,以及抽提物对MRSA细胞膜完整性的破坏作用等。结果 乳酸菌粗提物HS011、HS023、HS033对MRSA的MIC分别为5.75、5.00、6.00mg/mL;指示菌MRSA的生长过程受到粗提物明显抑制,在6h时HS011、HS023、HS033对MRSA的抑菌率分别为28.69%、69.20%和42...  相似文献   

13.
Hypothiocyanite has been known as antimicrobial agent that was generated from lactoperoxidase system (LPOS) but its antimicrobial activity was low against pathogenic bacteria in milk. This research has been done to enhance the antimicrobial activity of hypothiocyanite against pathogenic bacteria commonly found in milk: Staphylococcus aureus and Escherichia coli by addition of carrot extract. The result showed that carrot extract was able to enhance the antimicrobial activity of hypothiocyanite strongly against E. coli, however less enhancement has been found in the antibacterial activity of hypothiocyanite against S. aureus.  相似文献   

14.
The aim of this work was to examine the chemical composition of the essential oil and various solvent extracts isolated from the floral cone of Metasequoia glyptostroboides Miki ex Hu and to test their efficacy against a diverse range of organisms comprising food spoilage and food-borne pathogenic bacteria. The chemical composition of essential oil isolated by hydrodistillation was analysed by GC-MS. It was determined that 59 compounds, which represented 97.06% of total oil, were present in the oil. The oil contains mainly α-pinene (29.54%), totarol (9.37%), α-thujene (8.63%), bornylene (8.63%), β-caryophyllene (4.40%), totarol acetate (3.98%), δ-3-carene (3.19%) and 2-β-pinene (2.25%). The oil was found containing mainly the oxygenated mono- and sesquiterpenes and their respective hydrocarbons. Antibacterial activity of essential oil, methanol extract and various organic sub-fractions of methanol extract of M. glyptostroboides was determined in vitro using agar diffusion method and MIC determination test against eleven (four Gram-positive, seven Gram-negative) bacterial strains including food spoilage and food-borne pathogens. The essential oil (5 μl/ml, corresponding to 1000 ppm/disc), methanol extract and various organic sub-fractions (7.5 μl/ml, corresponding to 1500 ppm/disc) of M. glyptostroboides exhibited great potential of antibacterial activity against four Gram-positive bacteria such as Bacillus subtilis (ATCC 6633), Listeria monocytogenes (ATCC 19166), Staphylococcus aureus (KCTC 1916), S. aureus (ATCC 6538) and one Gram-negative bacterium, Pseudomonas aeruginosa (KCTC 2004). The zones of inhibition of different concentrations of essential oil, methanol extract and its derived various organic sub-fractions against the tested bacteria were found in the range of 10 ∼ 20 mm and the MIC values were recorded between 125 and 1000 μg/ml. This study shows that M. glyptostroboides mediated essential oil and extracts can be applied in food industries as a natural preservatives or flavoring additives to control food spoilage and food-borne pathogenic bacteria causing severe destruction in food.  相似文献   

15.
Two alkaloids, stephanine and crebanine, were isolated from tubers of the traditional Chinese medicinal plant Stephania dielsiana, using an activity-directed isolation method, and inhibitory activity of methanol extract, stephanine and crebanine against ten animal pathogenic bacteria and eight plant pathogenic fungi was evaluated in vitro. The results showed that extract from S. dielsiana exhibited high inhibitory activity against five gram-positive and four gram-negative animal pathogenic bacteria, with MIC values of 0.625–7.5 g/l; stephanine and crebanine had high inhibitory activity against gram-positive animal pathogenic bacteria, with MIC values of 0.078–0.312 g/l, but low inhibitory activity against gram-negative animal pathogenic bacteria. Methanol extract, stephanine and crebanine also inhibited hyphal growth of the plant pathogens Cercospora kaki, Gymnosporangium haraeanum, Pyricularia oryzae, Rhizoctonia solani and Colletotrichum graminicola, and spores germination of Thielaviopsis paradoxa, Fusarium oxysporum f. sp. niveum, Sphaceloma fawcettii and G. haraeanum.  相似文献   

16.
The antimicrobial activity of bioconversion extracts of EPA and DHA against a range of foodborne pathogenic bacteria was investigated. The bioconverted EPA and DHA exhibited antibacterial activities against four gram-positive bacteria, Bacillus subtilis, Listeria monocytogenes, Staphylococcus aureus (ATCC 6538) and S. aureus (KCTC 1916) and seven gram-negative bacteria, Enterobacter aerogenes, Escherichia coli, E. coli O157:H7, E. coli O157:H7 (human), Pseudomonas aeruginosa, Salmonella enteritidis and S. typhimurium. The growth inhibition by both bioconverted EPA and DHA was similar against gram-positive bacteria, while the bioconverted extract of DHA was more effective than EPA against gram-negative bacteria as determined by minimum inhibitory concentration.  相似文献   

17.
The aim of this study was to determine the total phenolic contents and antibacterial effects of grape pomace extracts (cultivars Emir and Kalecik karasi) against 14 bacteria, and the effects of the extracts on the growth and survival of two of the bacteria during storage. The total phenolic contents of grape pomace of Emir and Kalecik karasi cultivars extracted with acetone/water/acetic acid (90:9.5:0.5) were 68.77 and 96.25 mg GAE g?1, respectively. The agar well diffusion method was used to test the antibacterial activity of the extracts at 1, 2.5, 5, 10 and 20% (w/v) concentrations in methanol on spoilage and pathogenic bacteria including Aeromonas hydrophila, Bacillus cereus, Enterobacter aerogenes, Enterococcus faecalis, Escherichia coli, Escherichia coli O157:H7. Mycobacterium smegmatis, Proteus vulgaris, Pseudomonas aeruginosa, Pseudomonas fluorescens, Salmonella enteritidis, Salmonella typhimurium, Staphylococcus aureus and Yersinia enterocolitica. All the bacteria tested were inhibited by extract concentrations of 2.5, 5, 10 and 20%, except for Y enterocolitica which was not inhibited by the 2.5% concentration. However, pomace extracts at 1% concentration had no antibacterial activity against some of the bacteria. According to the agar well diffusion method, E coli O157:H7 was the most sensitive of the bacteria. Generally, using the serial dilution method, while the extracts at 0.5% concentration had bacteriostatic activities on E coli O157:H7 and S aureus, the extracts appeared to have bactericidal effects at 1 and 2.5% concentrations. In accordance with this method, S aureus was more sensitive than E coli O157:H7 to the extracts. Copyright © 2004 Society of Chemical Industry  相似文献   

18.
Preliminary phytochemical and flavonoid compounds of aqueous and ethanolic extracts of 6 aromatic Malaysian herbs were screened and quantified using Reverse‐Phase High Performance Liquid Chromatography (RP‐HPLC). The herbal extracts were tested for their antimicrobial activity against 10 food‐borne pathogenic and food spoilage microorganisms using disk diffusion assay. The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC)/minimum fungicidal concentration (MFC) of herbal extracts were determined. In the phytochemical screening process, both aqueous and ethanolic extracts of P. hydropiper exhibited presence of all 7 tested phytochemical compounds. Among all herbal extracts, the aqueous P. hydropiper and E. elatior extracts demonstrated the highest antibacterial activity against 7 tested Gram‐positive and Gram‐negative bacteria with diameter ranging from 7.0 to 18.5 mm and 6.5 to 19 mm, respectively. The MIC values for aqueous and ethanolic extracts ranged from 18.75 to 175 mg/mL and 0.391 to 200 mg/mL, respectively while the MBC/MFC values for aqueous and ethanolic extracts ranged from 25 to 200 mg/mL and 3.125 to 50 mg/mL, respectively. Major types of bioactive compounds in aqueous P. hydropiper and E. elatior extracts were identified using RP‐HPLC instrument. Flavonoids found in these plants were epi‐catechin, quercetin, and kaempferol. The ability of aqueous Persicaria hydropiper (L.) H. Gross and Etlingera elatior (Jack) R.M. Sm. extracts to inhibit the growth of bacteria is an indication of its broad spectrum antimicrobial potential. Hence these herbal extracts may be used as natural preservative to improve the safety and shelf‐life of food and pharmaceutical products.  相似文献   

19.
本文研究了茶槲寄生“螃蟹脚”醇提各萃取相的抑菌作用及正丁醇萃取相(NVBEs)对金黄色葡萄球菌的抑菌机理。采用滤纸片扩散法测定抑菌圈直径(DIZ)的大小,对倍稀释法测定最小抑菌浓度(MIC)和最低杀菌浓度(MBC),来评价“螃蟹脚”醇提各萃取相对金黄色葡萄球菌(S. aureus)、大肠杆菌(E. coli)、鼠伤寒沙门氏菌(S. typhimurium)、单核细胞增生李斯特菌(L. monocytogenes)4种食源性腐败菌的抑制性;通过光学显微镜和扫描电镜观察、胞膜通透性、胞壁完整性和酶活性等实验,研究了NVBEs抑菌机理。结果表明,“螃蟹脚”醇提各萃取相对S. aureus、E. coli、S. typhimurium和L. monocytogenes均有明显抑制效果,其中NVBEs抑菌活性较好,对S. aureus抑制效果最好,DIZ为9.84±0.57 mm,MIC为3.52 mg/mL,MBC为7.04 mg/mL。抑菌机理结果表明:NVBEs可增加S. aureus细胞壁及细胞膜的通透性,破坏菌体细胞结构,引起细胞内含物如核酸和蛋白质等外泄;引起遗传物质DNA的改变,使菌体细胞形态结构出现异常;影响菌体酶的代谢活动,从而抑制细菌的生长。  相似文献   

20.
The fungal plant infection caused by Colletotrichum gloeosporioides known as anthracnose, affects tropical fruits thus causing low yield and poor fruit quality. The antifungal activity of ethanol and chloroform extracts of different Mexican plants jarilla (Baccharis salicifolia), tepozan (Buddleia americana), nanche (Byrsonima cordata), cinco negritos (Lantana camara), Mexican oregano (Lippia berlandieri var. Scanner), and pericon (Tagetes lucida) against C. gloeosporioides were evaluated by determining the minimum inhibitory concentration (MIC) of the ethanol and chloroform extracts. Subsequently, an antifungal assay was carried out by determining the inhibition of radial growth in PDA plates added with plant extracts. Jarilla, oregano, and pericon MIC values were 400 mg/L for ethanol extracts and 200 mg/L for chloroform extracts. Tepozan, nanche, and cinco negritos showed no antifungal effect. Concerning the inhibition of radial growth, pericon ethanol extract showed an 84% inhibition; chloroform extracts of jarilla, oregano, and pericon showed 88%, 90%, and 95% inhibition, respectively. The ethanol extracts of oregano and jarilla demonstrated to be inhibitory at the reproductive phase of C. gloeosporioides, while their chloroform extracts have a fungistatic effect.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号