[Objective] The study was to explore whether antimicrobial activity of the antimicrobial peptides extracted from immunized Tenebrio molitor varied with different pathogens as inducers.[Method]By inducing T.molitor hun...[Objective] The study was to explore whether antimicrobial activity of the antimicrobial peptides extracted from immunized Tenebrio molitor varied with different pathogens as inducers.[Method]By inducing T.molitor hungry larvaes to generate immune response via feeding with bacteria and with fungi or actinomycete post to pricking,the antimicrobial peptides extracts were obtained by grinding and centrifuging the cultures.Its antimicrobial activity against 26 pathogens was measured by bacteriostatic ring,and evaluated by trisection to four types and inhibitory spectrum.[Result]Both the antimicrobial activity and antimicrobial spectrum of the antimicrobial peptides extracts varied remarkably among different pathogens as inducers.[Conclusion]Bio-control used strains have obvious advantage in inducing the insect to express body fluid immunity material-antimicrobial peptides.展开更多
Objective： This study examined the antimicrobial activity of Cannabis sativa, Thuja orientalis and Psidium guajava against methicillin-resistant Staphylococcus aureus （MRSA） and used a standardized purification pro...Objective： This study examined the antimicrobial activity of Cannabis sativa, Thuja orientalis and Psidium guajava against methicillin-resistant Staphylococcus aureus （MRSA） and used a standardized purification protocol to determine the presence and abundance of bioactive compounds in the leaf extracts. Methods： In vitro antimicrobial activities of the ethanolic extracts of C sativa, T. orientalis and P. guajava were tested against MRSA. The presence of bioactive molecules in these three leaves was evaluated using biochemical assays and high-performance thin-layer chromatography （HPTLC）. Results： Resistance to methicillin, penicillin, oxacillin and cefoxitin was observed in each of the clinical and nonclinical MRSA isolates. However, they were still vulnerable to vancomydn. Used individually, the 50% extract of each plant leaf inhibited MRSA growth. A profound synergism was observed when C sativa was used in combination with T. orientalis （1：1 ） and when P. guajava was used in combination with T. orientalis （1：1 ）. This was shown by larger zones of inhibition. This synergism was probably due to the combined inhibitory effect of phenolics present in the leaf extracts （i.e., quercetin and gallic acid） and catechin, as detected by HPTLC. Conclusion： The leaf extracts of C sativa, T. orientalis and P. guajava had potential for the control of both hospital- and community-acquired MRSA. Moreover, the inhibitory effect was enhanced when extracts were used in combination.展开更多
A new series of fatty alkenoates were synthesized using an appropriate synthetic route involving DCC and DMAP as catalysts. Compounds were characterized by their spectral data.All the synthesized compounds were evalua...A new series of fatty alkenoates were synthesized using an appropriate synthetic route involving DCC and DMAP as catalysts. Compounds were characterized by their spectral data.All the synthesized compounds were evaluated for their in vitro antimicrobial activity.The minimum inhibitory concentration(MIC),minimum bacterial concentration(MBC) and minimum fungicidal concentration(MFC) were determined for test compounds as well as for reference standards.Among the compounds tested, compounds having hydroxy group at the fatty acid chain showed the most potent antibacterial as well as antifungal activities.展开更多
Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was des...Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was described as the preparation of tetrazolo[1,5-α]quinoline based 1,4-dihydropyridines,acridine-1,8-diones and polyhydroquinolines.The process presented here is simple,rapid,environmentally welcoming and high yielding.All the derivatives were subjected to an in vitro antimicrobial screening against a representative panel of bacteria and fungi and results worth further investigations.展开更多
The chemical composition and antimicrobial potential of Cistus munbyi essential oil were studied for the first time. GC and GC–MS analysis revealed 48 compounds representing 96.98% of the oil. Terpinen-4-ol(23.75%), ...The chemical composition and antimicrobial potential of Cistus munbyi essential oil were studied for the first time. GC and GC–MS analysis revealed 48 compounds representing 96.98% of the oil. Terpinen-4-ol(23.75%), meta-Cymene(17.30%), and Sabinene(12.38%)were the major constituents. Antimicrobial activity was evaluated against nine pathogens using the disc diffusion and broth micro-dilution methods. Results show that C.munbyi essential oil possesses strong antimicrobial activity against all strains, regardless if Gram-positive or Gramnegative bacteria, or yeast, with MICs values not exceeding10(mg/ml). In addition to its efficacy, C. munbyi essential oil has an unusual antimicrobial potency which is attributed to its specific chemical composition. Thus, findings presented here suggest that endemic C. munbyi contains a very interesting essential oil that may be valuable in several areas.展开更多
Bipolarins A–H(1–8), eight new tetracyclic ophiobolin-type sesterterpenes featuring a rare oxaspiro[4.4]nonane moiety, were isolated from cultures of fungus Bipolaris sp. TJ403-B1. Their structures and absolute conf...Bipolarins A–H(1–8), eight new tetracyclic ophiobolin-type sesterterpenes featuring a rare oxaspiro[4.4]nonane moiety, were isolated from cultures of fungus Bipolaris sp. TJ403-B1. Their structures and absolute configurations were elucidated by comprehensive spectroscopic analyses, single-crystal X-ray diffraction experiments, electronic circular dichroism and 13 C NMR calculations. Additionally, compound 5 exhibited significant selective antimicrobial activity against Enterococcus faecalis with an MIC value 8 μg·mL^-1.展开更多
A new series of imidazole-containing 1, 5-benzodiazepines have been synthesized by the condensation of chalcones with o- phenylenediamine using piperidine in polyethylene glycol （PEG-400） as an efficient and green r...A new series of imidazole-containing 1, 5-benzodiazepines have been synthesized by the condensation of chalcones with o- phenylenediamine using piperidine in polyethylene glycol （PEG-400） as an efficient and green reaction solvent. The advantages of this protocol are environmental friendliness, easy work-up, high yields, mild reaction condition and avoidance of expensive catalyst. Furthermore, newly synthesized compounds were evaluated for their antimicrobial activity.展开更多
A new series of N-arylquinoline derivatives 5a-x bearing 2-morpholinoquinoline moiety has been synthesized by one pot base catalyzed cyclocondensation reaction of 2-morpholinoquinoline-3-carbaldehydes 2a-c,malononitri...A new series of N-arylquinoline derivatives 5a-x bearing 2-morpholinoquinoline moiety has been synthesized by one pot base catalyzed cyclocondensation reaction of 2-morpholinoquinoline-3-carbaldehydes 2a-c,malononitrile 3 andβ-enaminones 4a-h. All the synthesized compounds were screened for their in vitro antimicrobial activity against six bacterial pathogens,namely Streptococcus pneumoniae,Clostridium tetani,Bacillus subtilis,Salmonella typhi,Vibrio cholerae,Escherichia coli and against two fungal pathogens,Aspergillus fumigatus and Candida albicans using broth microdilution MIC method.Of the compounds studied,majority of the compounds were found to active against C.tetani,B.subtilis and C.albicans as compared to first-line standard drugs.展开更多
A series of some new quinoline based imidazole-5-one derivatives have been synthesized by the fusion of oxazol-5-ones,various p-substituted anilines and zeolite in pyridine.All the derivatives were subjected to an in ...A series of some new quinoline based imidazole-5-one derivatives have been synthesized by the fusion of oxazol-5-ones,various p-substituted anilines and zeolite in pyridine.All the derivatives were subjected to an in vitro antimicrobial screening against a representative panel of bacteria and fungi and results worth further investigations.展开更多
The purpose of this study was to assess the efficacy of alexidine（ALX）,alone and combined with N-acetylcysteine（NAC）,in eradicating two Enterococcus faecalis strain biofilms.The biofilms of E.faecalis ATCC 29212 a...The purpose of this study was to assess the efficacy of alexidine（ALX）,alone and combined with N-acetylcysteine（NAC）,in eradicating two Enterococcus faecalis strain biofilms.The biofilms of E.faecalis ATCC 29212 and the clinical isolate E.faecalis D1 were grown in the MBEC-high-throughput device for 24 h and were exposed to five twofold dilutions of ALX（2%–0.007 8%）alone and combined with100 mg？mL21NAC,for 1 and 5 min.Eradication was defined as 100%kill of biofilm bacteria.The Student’s t-test was used to compare the efficacy of the associations of the two irrigants.After 1-min contact time,ALX eradicated the biofilms at all concentrations except for 0.007 8%and 0.015 6%–0.007 8%with E.faecalis ATCC 29212 and E.faecalis D1,respectively.Similar results for eradication and concentration were obtained when it was combined with 100 mg？mL21NAC.After 5 min of contact time,ALX alone and combined with NAC eradicated all enterococci biofilms.ALX showed antimicrobial properties against the two E.faecalis strain biofilms tested at very low concentrations,and its combined use with NAC was not seen to enhance its activity.展开更多
A new friedelane-type triterpene named 3β-hydroxyfriedelane-7,12,22-trione,as well as nine known compounds were isolated from the whole stems of Drypetes laciniata Hutch.（Euphorbiaceae）.Their structures were establ...A new friedelane-type triterpene named 3β-hydroxyfriedelane-7,12,22-trione,as well as nine known compounds were isolated from the whole stems of Drypetes laciniata Hutch.（Euphorbiaceae）.Their structures were established on the basis of spectroscopic methods.The new triterpene derivative and a known saponin were tested for antimicrobial and antifungal activities and they appeared to be moderate active.展开更多
A series of 8,9-dihydro-2-（2-oxo-2H-chromen-3-yl）-5-aryl-3H-chromeno[2,3-d]pyrimidine-4,6（5H^7H）-diones （Sa-j）have been synthesized by the reaction of 2-amino-5,6,7,8-tetrahydro-5-oxo-4-aryl-4H-chromene-3-carbon...A series of 8,9-dihydro-2-（2-oxo-2H-chromen-3-yl）-5-aryl-3H-chromeno[2,3-d]pyrimidine-4,6（5H^7H）-diones （Sa-j）have been synthesized by the reaction of 2-amino-5,6,7,8-tetrahydro-5-oxo-4-aryl-4H-chromene-3-carbonitrile （4a-j） with couma- rin-3-catboxylic acid under neat conditions employing Brnsted acidic ionic liquid （4-sulfobutyl）tris（4-sulfophenyl）phosphonium hydrogen sulfate as catalyst. Structures of all the compounds were established on the basis of analytical and spectroscopic data. All the compounds were evaluated for their in vitro antimicrobial activity against different bacterial and fungal strains.展开更多
The inhibition effect of chitooligosaccharides from housefly larvae on pathogens ofcrops seeds, fruits or vegetables was studied and the main factors influencing theantimicrobial activity of chitooligosaccharides were...The inhibition effect of chitooligosaccharides from housefly larvae on pathogens ofcrops seeds, fruits or vegetables was studied and the main factors influencing theantimicrobial activity of chitooligosaccharides were also investigated. It was foundthat chitooligosaccharides from housefly larvae had wide spectrum fungistasis. It canstrongly inhibit the development of 31 kinds of plant pathogenic fungi such as corticiumrolfsii Saccardo. The results indicated that the degree of deacelylation (DD) or theaverage molecular weight(MW)of chitooligosaccharides were related to the antimicrobialactivity. The antimicrobial activity increased with the rising of DD or the declining ofMW. Pot culture results showed that chitooligosaccharide could enhance the rate ofgermination and emergence of the seeds of maize, wheat and cotton. Chitooligosaccharidehad certain effect on corn southern leaf blight caused by Helminthosporium maydis.展开更多
Antibacterial activity of boron-doped TiO2(B/TiO2) nano-materials under visible light irradiation and in the dark was investigated. A simple sol-gel method was used to synthesize TiO2 nano-materials. X-ray diffraction...Antibacterial activity of boron-doped TiO2(B/TiO2) nano-materials under visible light irradiation and in the dark was investigated. A simple sol-gel method was used to synthesize TiO2 nano-materials. X-ray diffraction pattern of B/TiO2 nano-materials represents the diffraction peaks relating to the crystal planes of TiO2(anatase and rutile). X-ray photoelectron spectroscopy result shows that part of boron ions incorporates into TiO2 lattice to form a possible chemical environment like Ti O B and the rest exist in the form of B2O3. The study on antibacterial effect of B/TiO2 nano-materials on fungal Candida albicans(ATCC10231), Gram-negative Escherichia coli(ATCC25922) and Gram-positive Staphylococcus aureus(ATCC6538) shows that the antibacterial action is more significant on Candida albicans than on Escherichia coli and Staphylococcus aureus. Under visible light irradiation, the antibacterial activity is superior to that in the dark.展开更多
[ Objective ] The paper was to explore the antimicmbial activities of extracts from Xylaria striata via submerged culture. [ Methods ] The antibacterial activities of X. striata extracts against 10 kinds of bacteria w...[ Objective ] The paper was to explore the antimicmbial activities of extracts from Xylaria striata via submerged culture. [ Methods ] The antibacterial activities of X. striata extracts against 10 kinds of bacteria were determined using Oxford cup method and mJcroplate assay, and the antifungal activities against nine kinds of pathogenic fungi were determined using mycelial growth rate method. [ Results ] The inhibition zone diameters of the mycelium extract against tested bacte- ria ranged from 13.0 to 17.5 mm, and that of the fermentation broth extract ranged from 10.5 to 12.7 ram. Enterobacter cloacae was the most sensitive to both my- celium extract and fermentation broth extract, with the inhibition zone diameters of 17.1 and 12.7 mm and the minimum inhibitory concentrations of 2.5 and 5 mg/mL, respectively. The inhibitory effects of the mycelium extract and the fermentation broth extract against Fusarium graminearum were the greatest, and the in- hibition rates were 89.88% and 69.53%, respectively. [ Conclusion] X. striata has potential antimicrobial activity and deserves to be further studied.展开更多
Objective：To explore a new natural antibiotic. Methods：The chemical composition of the essential oil from Ganodermajaponicum （G. japonicum）mycelia was analyzed by gas chromatography-mass spectrometry（GC-MS）, The...Objective：To explore a new natural antibiotic. Methods：The chemical composition of the essential oil from Ganodermajaponicum （G. japonicum）mycelia was analyzed by gas chromatography-mass spectrometry（GC-MS）, The antimicrobial activity of the oil was evaluated against eighteen microorganisms, including bacteria, mildew and yeast by using a disc diffusion method. Furthermore, the minimum inhibitory concentrations（MIC） and the minimum bactericidal concentrations（MBC） of the essential oil against twelve clinical pathogens were determined. Results：The main components of the oil were nerolidol, decadienal, linalool and benzyl alcohol. The antimicrobial results indicated that the oil inhibited all the tested bacterium, especially Methicillin-resistant Staphylococcus aureus （MRSA） in which the antibacterial activity exhibited a MBC of 1.03 mg/ml. Conclusion： The essential oil of G. japonicum mycelium has significant inhibitory activity. It is a potential medicinal resource that can be used as a natural antibiotic.展开更多
[ Objective ] This study aimed to investigate the antimicrobial activity of hybrid antimicrobial peptide buforin II-cecropin B. [ Method ] Gene fragment BC encoding the hybrid antimicrobial peptide Buforin II-Cecropin...[ Objective ] This study aimed to investigate the antimicrobial activity of hybrid antimicrobial peptide buforin II-cecropin B. [ Method ] Gene fragment BC encoding the hybrid antimicrobial peptide Buforin II-Cecropin B was synthesized by SOE-PCR with six primers designed according to the published amino acid sequences. Then, the BC gene fragment was ligated into pET32a vector and expressed in BI21. Antimierobial ability of the crude hybrid antimicrobial peptide was detected with the Oxford cup method. [ Result] The BC gene fragment was correctly amplified by SOE-PCR and ligated into pET32a vector, to construct the expression vector pET32-BC. The hybrid antimicrobial peptide buforin II-cecropin B was expressed in BI21 after induction by IPTG. The optimal induction time was 2 h. Antimicrobial activity assay suggested that the hybrid antimicrobial peptide possessed antimicrobial activity to Escherichia coli and Bacillus subtilis. [ Conclusion] The hybrid antimicrobial peptide buforin II-cecropin B exhibited antimicrobial activity to Gram-negative E. coli and Gram-positive B. subtilis strains.展开更多
A novel series of quaternary ammonium cationic derivatives based on tetrapyridyl-porphyrin was synthesized. All the compounds were evaluated for their in vitro antibacterial activities against S. aureus, E. coli and P...A novel series of quaternary ammonium cationic derivatives based on tetrapyridyl-porphyrin was synthesized. All the compounds were evaluated for their in vitro antibacterial activities against S. aureus, E. coli and P. aeruginosa, and antifungal activities against C. albicans, where microorganisms were exposed and unexposed to the irradiation. The results revealed that some of these compounds, especially, 3a and 4a displayed satisfactory antibacterial activity against Gram-positive bacteria S. aureus and moderate antifungal activity against C. albicans. Unfortunately, Gram-negative bacteria P aeruginasa was resistant to all compounds. The antimicrobial activity was found to be sensitive to the functional groups attached on the aromatic ring and the complex metal in the porphyrin ring, and decreased with the increase of electron-withdrawing capability of the functional groups. These preliminary results suggested that the remarkable antibacterial efficiency against S. aureus makes these substances promising antimicrobial agents.展开更多
Objective:To isolate and evaluate the antimicrobial activity of the active principle(s)from the ethyl acetate(EtOAc)extract of endophytic fungus Colietotrichum gloeosporioides(C.gloeosporioides)isolated from Sonnerati...Objective:To isolate and evaluate the antimicrobial activity of the active principle(s)from the ethyl acetate(EtOAc)extract of endophytic fungus Colietotrichum gloeosporioides(C.gloeosporioides)isolated from Sonneratia apetala.Methods:Water agar technique was used to isolate the fungus,and both microscopic and molecular techniques were used for identification of the strain.Potato dextrose broth was used to grow the fungus in large-scale.Reversed-phase preparative HPLC analysis was performed to isolate the major active compound,kojic acid.The EtOAc extract and kojic acid were screened for their antimicrobial activity against two Grampositive and two Gram-negative bacteria as well as a fungal strain using the resazurin 96-well microtitre plate antimicrobial assay.Results:The fungus C.gloeosporioides was isolated from the leaves of Sonneratia apetala.Initial identification of the fugal isolate was carried out using spore characteristics observed under the microscope.Subsequently,the ITS1-5.8 S-ITS2 sequencing was employed for species-level identification of the fungus C.gloeosporioides.Five litres of liquid culture of the fungus produced approximately 610 mg of a mixture of secondary metabolites.Kojic acid(1)was isolated as the main secondary metabolite present in the fungal extract,and the structure was confirmed by 1 D,2 D NMR and mass spectrometry.The EtOAc extract and compound 1 exhibited considerable antimicrobial activity against all tested microorganisms.Whilst the minimum inhibitory concentration(MIC)values from the EtOAc extract ranged between 2.4×10^(-4)mg/mL and 2.5 mg/mL,those of kojic acid(1)were between 0.125 mg/mL and1 mg/mL.The EtOAc extract and kojic acid(1)were most active against Pseudomonas aeruginosa(MIC=2.4×10^(-4).mg/mL)and Micrococcus luteus(MIC=0.125 mg/mL),respectively.Conclusions:The results revealed that the endophytic fungus C.gloeosporioides could be a good source of commercially important kojic acid,which exhibited antimicrobial properties.展开更多
Objective: To investigate chemical constituents and new antimicrobial agents among essential oils from the rhizomes of Curcuma aeruginosa(C. aeruginosa) Roxb., Curcuma glans K. Larsen & J. Mood and Curcuma cf. xan...Objective: To investigate chemical constituents and new antimicrobial agents among essential oils from the rhizomes of Curcuma aeruginosa(C. aeruginosa) Roxb., Curcuma glans K. Larsen & J. Mood and Curcuma cf. xanthorrhiza Roxb.Methods: The essential oils were obtained by hydro-distillation and analyzed by gas chromatography/mass spectroscopy. Agar-well diffusion assay was used to study the antimicrobial activity and also broth-micro dilution techniques were examined for minimum inhibitory concentration(MIC) against four bacterial strains and yeast.Results: The gas chromatography/mass spectroscopy analysis showed monoterpenes predominantly(88.53%) in the rhizome oil of Curcuma cf. xanthorrhiza. Sesquiterpenes(50.10%) was the most abundant component in the essential oil of C. glans, while monoterpenes(45.55%) and sesquiterpenes(45.81%) were found in C. aeruginosa with a significant amount. The major components of C. aeruginosa were characterized as camphor(29.39%) and germacrone(21.21%). Germacrone(15.76%), b-pinene(9.97%)and camphor(9.96%) were found as major compounds in the rhizome oils of C. glans while a-terpinolene(24.86%) and p-cymen-7-ol(12.17%) were found as major compositions in Curcuma cf. xanthorrhiza. The essential oils were tested against four bacterial strains and yeast. As a result, the rhizome oil of C. aeruginosa exhibited potent activity against Staphylococcus aureus [inhibition zone(21.94 ± 0.24) mm, MIC 125 μg/mL],Bacillus cereus [inhibition zone(20.83 ± 0.36) mm, MIC 125 μg/mL], and Candida albicans [inhibition zone(11.60 ± 0.30) mm, MIC 250 μg/mL].Conclusions: The essential oils from three Curcuma species possessed greater activity against the gram-positive bacteria(Staphylococcus aureus and Bacillus cereus) than gram-negative bacteria(Escherichia coli and Pseudomonas aeruginosa). The results suggest that the essential oils from the fresh rhizome of Curcuma spp. might be a potential source of natural antimicrobial substances.展开更多
基金Supported by Natural Science Foundation of Hebei Province(C200700450)~~
文摘[Objective] The study was to explore whether antimicrobial activity of the antimicrobial peptides extracted from immunized Tenebrio molitor varied with different pathogens as inducers.[Method]By inducing T.molitor hungry larvaes to generate immune response via feeding with bacteria and with fungi or actinomycete post to pricking,the antimicrobial peptides extracts were obtained by grinding and centrifuging the cultures.Its antimicrobial activity against 26 pathogens was measured by bacteriostatic ring,and evaluated by trisection to four types and inhibitory spectrum.[Result]Both the antimicrobial activity and antimicrobial spectrum of the antimicrobial peptides extracts varied remarkably among different pathogens as inducers.[Conclusion]Bio-control used strains have obvious advantage in inducing the insect to express body fluid immunity material-antimicrobial peptides.
基金Saaii Educational Foundation, Kanpur-209203,India,for their financial assistance
文摘Objective： This study examined the antimicrobial activity of Cannabis sativa, Thuja orientalis and Psidium guajava against methicillin-resistant Staphylococcus aureus （MRSA） and used a standardized purification protocol to determine the presence and abundance of bioactive compounds in the leaf extracts. Methods： In vitro antimicrobial activities of the ethanolic extracts of C sativa, T. orientalis and P. guajava were tested against MRSA. The presence of bioactive molecules in these three leaves was evaluated using biochemical assays and high-performance thin-layer chromatography （HPTLC）. Results： Resistance to methicillin, penicillin, oxacillin and cefoxitin was observed in each of the clinical and nonclinical MRSA isolates. However, they were still vulnerable to vancomydn. Used individually, the 50% extract of each plant leaf inhibited MRSA growth. A profound synergism was observed when C sativa was used in combination with T. orientalis （1：1 ） and when P. guajava was used in combination with T. orientalis （1：1 ）. This was shown by larger zones of inhibition. This synergism was probably due to the combined inhibitory effect of phenolics present in the leaf extracts （i.e., quercetin and gallic acid） and catechin, as detected by HPTLC. Conclusion： The leaf extracts of C sativa, T. orientalis and P. guajava had potential for the control of both hospital- and community-acquired MRSA. Moreover, the inhibitory effect was enhanced when extracts were used in combination.
文摘A new series of fatty alkenoates were synthesized using an appropriate synthetic route involving DCC and DMAP as catalysts. Compounds were characterized by their spectral data.All the synthesized compounds were evaluated for their in vitro antimicrobial activity.The minimum inhibitory concentration(MIC),minimum bacterial concentration(MBC) and minimum fungicidal concentration(MFC) were determined for test compounds as well as for reference standards.Among the compounds tested, compounds having hydroxy group at the fatty acid chain showed the most potent antibacterial as well as antifungal activities.
文摘Microwave assisted efficient Hantzsch reaction via four-component coupling reactions of tetrazolo[1,5-α]quinoline-4-carbal-dehyde, dimedone/cyclohexane-1,3-dione,ethyl/methyl acetoacetate and ammonium acetate was described as the preparation of tetrazolo[1,5-α]quinoline based 1,4-dihydropyridines,acridine-1,8-diones and polyhydroquinolines.The process presented here is simple,rapid,environmentally welcoming and high yielding.All the derivatives were subjected to an in vitro antimicrobial screening against a representative panel of bacteria and fungi and results worth further investigations.
基金supported by the Ministry of Higher Education and Scientific Research of People’s Democratic Republic of Algeria(Grant No.F02020110081)
文摘The chemical composition and antimicrobial potential of Cistus munbyi essential oil were studied for the first time. GC and GC–MS analysis revealed 48 compounds representing 96.98% of the oil. Terpinen-4-ol(23.75%), meta-Cymene(17.30%), and Sabinene(12.38%)were the major constituents. Antimicrobial activity was evaluated against nine pathogens using the disc diffusion and broth micro-dilution methods. Results show that C.munbyi essential oil possesses strong antimicrobial activity against all strains, regardless if Gram-positive or Gramnegative bacteria, or yeast, with MICs values not exceeding10(mg/ml). In addition to its efficacy, C. munbyi essential oil has an unusual antimicrobial potency which is attributed to its specific chemical composition. Thus, findings presented here suggest that endemic C. munbyi contains a very interesting essential oil that may be valuable in several areas.
基金supported by the Program for Changjiang Scholars of Ministry of Education of the People’s Republic of China(No.T2016088)the National Natural Science Foundation for Distinguished Young Scholars(No.81725021)+2 种基金the Innovative Research Groups of the National Natural Science Foundation of China(No.81721005)the National Natural Science Foundation of China(Nos.81573316,21702067,and 81803387)the Hubei Provincial Natural Science Foundation of China(No.2018CFB152)
文摘Bipolarins A–H(1–8), eight new tetracyclic ophiobolin-type sesterterpenes featuring a rare oxaspiro[4.4]nonane moiety, were isolated from cultures of fungus Bipolaris sp. TJ403-B1. Their structures and absolute configurations were elucidated by comprehensive spectroscopic analyses, single-crystal X-ray diffraction experiments, electronic circular dichroism and 13 C NMR calculations. Additionally, compound 5 exhibited significant selective antimicrobial activity against Enterococcus faecalis with an MIC value 8 μg·mL^-1.
文摘A new series of imidazole-containing 1, 5-benzodiazepines have been synthesized by the condensation of chalcones with o- phenylenediamine using piperidine in polyethylene glycol （PEG-400） as an efficient and green reaction solvent. The advantages of this protocol are environmental friendliness, easy work-up, high yields, mild reaction condition and avoidance of expensive catalyst. Furthermore, newly synthesized compounds were evaluated for their antimicrobial activity.
文摘A new series of N-arylquinoline derivatives 5a-x bearing 2-morpholinoquinoline moiety has been synthesized by one pot base catalyzed cyclocondensation reaction of 2-morpholinoquinoline-3-carbaldehydes 2a-c,malononitrile 3 andβ-enaminones 4a-h. All the synthesized compounds were screened for their in vitro antimicrobial activity against six bacterial pathogens,namely Streptococcus pneumoniae,Clostridium tetani,Bacillus subtilis,Salmonella typhi,Vibrio cholerae,Escherichia coli and against two fungal pathogens,Aspergillus fumigatus and Candida albicans using broth microdilution MIC method.Of the compounds studied,majority of the compounds were found to active against C.tetani,B.subtilis and C.albicans as compared to first-line standard drugs.
文摘A series of some new quinoline based imidazole-5-one derivatives have been synthesized by the fusion of oxazol-5-ones,various p-substituted anilines and zeolite in pyridine.All the derivatives were subjected to an in vitro antimicrobial screening against a representative panel of bacteria and fungi and results worth further investigations.
基金supported by the Research Group CTS-167 of the Junta de Andaluc'a,Spain
文摘The purpose of this study was to assess the efficacy of alexidine（ALX）,alone and combined with N-acetylcysteine（NAC）,in eradicating two Enterococcus faecalis strain biofilms.The biofilms of E.faecalis ATCC 29212 and the clinical isolate E.faecalis D1 were grown in the MBEC-high-throughput device for 24 h and were exposed to five twofold dilutions of ALX（2%–0.007 8%）alone and combined with100 mg？mL21NAC,for 1 and 5 min.Eradication was defined as 100%kill of biofilm bacteria.The Student’s t-test was used to compare the efficacy of the associations of the two irrigants.After 1-min contact time,ALX eradicated the biofilms at all concentrations except for 0.007 8%and 0.015 6%–0.007 8%with E.faecalis ATCC 29212 and E.faecalis D1,respectively.Similar results for eradication and concentration were obtained when it was combined with 100 mg？mL21NAC.After 5 min of contact time,ALX alone and combined with NAC eradicated all enterococci biofilms.ALX showed antimicrobial properties against the two E.faecalis strain biofilms tested at very low concentrations,and its combined use with NAC was not seen to enhance its activity.
基金grant(No.F/2624-3F) from the International Foundation for Science(Sweden)
文摘A new friedelane-type triterpene named 3β-hydroxyfriedelane-7,12,22-trione,as well as nine known compounds were isolated from the whole stems of Drypetes laciniata Hutch.（Euphorbiaceae）.Their structures were established on the basis of spectroscopic methods.The new triterpene derivative and a known saponin were tested for antimicrobial and antifungal activities and they appeared to be moderate active.
文摘A series of 8,9-dihydro-2-（2-oxo-2H-chromen-3-yl）-5-aryl-3H-chromeno[2,3-d]pyrimidine-4,6（5H^7H）-diones （Sa-j）have been synthesized by the reaction of 2-amino-5,6,7,8-tetrahydro-5-oxo-4-aryl-4H-chromene-3-carbonitrile （4a-j） with couma- rin-3-catboxylic acid under neat conditions employing Brnsted acidic ionic liquid （4-sulfobutyl）tris（4-sulfophenyl）phosphonium hydrogen sulfate as catalyst. Structures of all the compounds were established on the basis of analytical and spectroscopic data. All the compounds were evaluated for their in vitro antimicrobial activity against different bacterial and fungal strains.
文摘The inhibition effect of chitooligosaccharides from housefly larvae on pathogens ofcrops seeds, fruits or vegetables was studied and the main factors influencing theantimicrobial activity of chitooligosaccharides were also investigated. It was foundthat chitooligosaccharides from housefly larvae had wide spectrum fungistasis. It canstrongly inhibit the development of 31 kinds of plant pathogenic fungi such as corticiumrolfsii Saccardo. The results indicated that the degree of deacelylation (DD) or theaverage molecular weight(MW)of chitooligosaccharides were related to the antimicrobialactivity. The antimicrobial activity increased with the rising of DD or the declining ofMW. Pot culture results showed that chitooligosaccharide could enhance the rate ofgermination and emergence of the seeds of maize, wheat and cotton. Chitooligosaccharidehad certain effect on corn southern leaf blight caused by Helminthosporium maydis.
基金Supported by the National Natural Science Foundation of China(51090384)
文摘Antibacterial activity of boron-doped TiO2(B/TiO2) nano-materials under visible light irradiation and in the dark was investigated. A simple sol-gel method was used to synthesize TiO2 nano-materials. X-ray diffraction pattern of B/TiO2 nano-materials represents the diffraction peaks relating to the crystal planes of TiO2(anatase and rutile). X-ray photoelectron spectroscopy result shows that part of boron ions incorporates into TiO2 lattice to form a possible chemical environment like Ti O B and the rest exist in the form of B2O3. The study on antibacterial effect of B/TiO2 nano-materials on fungal Candida albicans(ATCC10231), Gram-negative Escherichia coli(ATCC25922) and Gram-positive Staphylococcus aureus(ATCC6538) shows that the antibacterial action is more significant on Candida albicans than on Escherichia coli and Staphylococcus aureus. Under visible light irradiation, the antibacterial activity is superior to that in the dark.
基金Supported by National Natural Science Foundation of China(21272189)Student Innovation Fund of Southwest University of Science and Technology(CX14-039)
文摘[ Objective ] The paper was to explore the antimicmbial activities of extracts from Xylaria striata via submerged culture. [ Methods ] The antibacterial activities of X. striata extracts against 10 kinds of bacteria were determined using Oxford cup method and mJcroplate assay, and the antifungal activities against nine kinds of pathogenic fungi were determined using mycelial growth rate method. [ Results ] The inhibition zone diameters of the mycelium extract against tested bacte- ria ranged from 13.0 to 17.5 mm, and that of the fermentation broth extract ranged from 10.5 to 12.7 ram. Enterobacter cloacae was the most sensitive to both my- celium extract and fermentation broth extract, with the inhibition zone diameters of 17.1 and 12.7 mm and the minimum inhibitory concentrations of 2.5 and 5 mg/mL, respectively. The inhibitory effects of the mycelium extract and the fermentation broth extract against Fusarium graminearum were the greatest, and the in- hibition rates were 89.88% and 69.53%, respectively. [ Conclusion] X. striata has potential antimicrobial activity and deserves to be further studied.
基金supported by the Natural Science Foundation of Hubei Province(2004ABA228)
文摘Objective：To explore a new natural antibiotic. Methods：The chemical composition of the essential oil from Ganodermajaponicum （G. japonicum）mycelia was analyzed by gas chromatography-mass spectrometry（GC-MS）, The antimicrobial activity of the oil was evaluated against eighteen microorganisms, including bacteria, mildew and yeast by using a disc diffusion method. Furthermore, the minimum inhibitory concentrations（MIC） and the minimum bactericidal concentrations（MBC） of the essential oil against twelve clinical pathogens were determined. Results：The main components of the oil were nerolidol, decadienal, linalool and benzyl alcohol. The antimicrobial results indicated that the oil inhibited all the tested bacterium, especially Methicillin-resistant Staphylococcus aureus （MRSA） in which the antibacterial activity exhibited a MBC of 1.03 mg/ml. Conclusion： The essential oil of G. japonicum mycelium has significant inhibitory activity. It is a potential medicinal resource that can be used as a natural antibiotic.
基金Supported by the Research Project of Sichuan University of Science&Engineering(No.2011RC12,2014KY02)Scientific Research Foundation of the Education Department of Sichuan Province(NO.15ZA0222)
文摘[ Objective ] This study aimed to investigate the antimicrobial activity of hybrid antimicrobial peptide buforin II-cecropin B. [ Method ] Gene fragment BC encoding the hybrid antimicrobial peptide Buforin II-Cecropin B was synthesized by SOE-PCR with six primers designed according to the published amino acid sequences. Then, the BC gene fragment was ligated into pET32a vector and expressed in BI21. Antimierobial ability of the crude hybrid antimicrobial peptide was detected with the Oxford cup method. [ Result] The BC gene fragment was correctly amplified by SOE-PCR and ligated into pET32a vector, to construct the expression vector pET32-BC. The hybrid antimicrobial peptide buforin II-cecropin B was expressed in BI21 after induction by IPTG. The optimal induction time was 2 h. Antimicrobial activity assay suggested that the hybrid antimicrobial peptide possessed antimicrobial activity to Escherichia coli and Bacillus subtilis. [ Conclusion] The hybrid antimicrobial peptide buforin II-cecropin B exhibited antimicrobial activity to Gram-negative E. coli and Gram-positive B. subtilis strains.
基金the School of Pharmacy of Southwest University for their partial support to this work.
文摘A novel series of quaternary ammonium cationic derivatives based on tetrapyridyl-porphyrin was synthesized. All the compounds were evaluated for their in vitro antibacterial activities against S. aureus, E. coli and P. aeruginosa, and antifungal activities against C. albicans, where microorganisms were exposed and unexposed to the irradiation. The results revealed that some of these compounds, especially, 3a and 4a displayed satisfactory antibacterial activity against Gram-positive bacteria S. aureus and moderate antifungal activity against C. albicans. Unfortunately, Gram-negative bacteria P aeruginasa was resistant to all compounds. The antimicrobial activity was found to be sensitive to the functional groups attached on the aromatic ring and the complex metal in the porphyrin ring, and decreased with the increase of electron-withdrawing capability of the functional groups. These preliminary results suggested that the remarkable antibacterial efficiency against S. aureus makes these substances promising antimicrobial agents.
基金financially supported by the Robert S McNamara Fellowship Programme from the World Bank offered to Tauhidur Rahman Nurunnabi
文摘Objective:To isolate and evaluate the antimicrobial activity of the active principle(s)from the ethyl acetate(EtOAc)extract of endophytic fungus Colietotrichum gloeosporioides(C.gloeosporioides)isolated from Sonneratia apetala.Methods:Water agar technique was used to isolate the fungus,and both microscopic and molecular techniques were used for identification of the strain.Potato dextrose broth was used to grow the fungus in large-scale.Reversed-phase preparative HPLC analysis was performed to isolate the major active compound,kojic acid.The EtOAc extract and kojic acid were screened for their antimicrobial activity against two Grampositive and two Gram-negative bacteria as well as a fungal strain using the resazurin 96-well microtitre plate antimicrobial assay.Results:The fungus C.gloeosporioides was isolated from the leaves of Sonneratia apetala.Initial identification of the fugal isolate was carried out using spore characteristics observed under the microscope.Subsequently,the ITS1-5.8 S-ITS2 sequencing was employed for species-level identification of the fungus C.gloeosporioides.Five litres of liquid culture of the fungus produced approximately 610 mg of a mixture of secondary metabolites.Kojic acid(1)was isolated as the main secondary metabolite present in the fungal extract,and the structure was confirmed by 1 D,2 D NMR and mass spectrometry.The EtOAc extract and compound 1 exhibited considerable antimicrobial activity against all tested microorganisms.Whilst the minimum inhibitory concentration(MIC)values from the EtOAc extract ranged between 2.4×10^(-4)mg/mL and 2.5 mg/mL,those of kojic acid(1)were between 0.125 mg/mL and1 mg/mL.The EtOAc extract and kojic acid(1)were most active against Pseudomonas aeruginosa(MIC=2.4×10^(-4).mg/mL)and Micrococcus luteus(MIC=0.125 mg/mL),respectively.Conclusions:The results revealed that the endophytic fungus C.gloeosporioides could be a good source of commercially important kojic acid,which exhibited antimicrobial properties.
基金supported by the grants from the Biodiversity-Based Economy Development Office Public Organization -National Research Council of Thailand(Grant number.R000012298)Department of Pharmaceutical Sciences,the Faculty of Pharmacy and the Graduate School,Chiang Mai University,Chiang Mai,Thailand
文摘Objective: To investigate chemical constituents and new antimicrobial agents among essential oils from the rhizomes of Curcuma aeruginosa(C. aeruginosa) Roxb., Curcuma glans K. Larsen & J. Mood and Curcuma cf. xanthorrhiza Roxb.Methods: The essential oils were obtained by hydro-distillation and analyzed by gas chromatography/mass spectroscopy. Agar-well diffusion assay was used to study the antimicrobial activity and also broth-micro dilution techniques were examined for minimum inhibitory concentration(MIC) against four bacterial strains and yeast.Results: The gas chromatography/mass spectroscopy analysis showed monoterpenes predominantly(88.53%) in the rhizome oil of Curcuma cf. xanthorrhiza. Sesquiterpenes(50.10%) was the most abundant component in the essential oil of C. glans, while monoterpenes(45.55%) and sesquiterpenes(45.81%) were found in C. aeruginosa with a significant amount. The major components of C. aeruginosa were characterized as camphor(29.39%) and germacrone(21.21%). Germacrone(15.76%), b-pinene(9.97%)and camphor(9.96%) were found as major compounds in the rhizome oils of C. glans while a-terpinolene(24.86%) and p-cymen-7-ol(12.17%) were found as major compositions in Curcuma cf. xanthorrhiza. The essential oils were tested against four bacterial strains and yeast. As a result, the rhizome oil of C. aeruginosa exhibited potent activity against Staphylococcus aureus [inhibition zone(21.94 ± 0.24) mm, MIC 125 μg/mL],Bacillus cereus [inhibition zone(20.83 ± 0.36) mm, MIC 125 μg/mL], and Candida albicans [inhibition zone(11.60 ± 0.30) mm, MIC 250 μg/mL].Conclusions: The essential oils from three Curcuma species possessed greater activity against the gram-positive bacteria(Staphylococcus aureus and Bacillus cereus) than gram-negative bacteria(Escherichia coli and Pseudomonas aeruginosa). The results suggest that the essential oils from the fresh rhizome of Curcuma spp. might be a potential source of natural antimicrobial substances.
