New cobalt(II) complex, [Co(O<sub>2</sub>C<sub>15</sub>H<sub>11</sub>N<sub>2</sub>S)<sub>2</sub>(OH<sub>2</sub>)<sub>2</sub>]∙2H<s...New cobalt(II) complex, [Co(O<sub>2</sub>C<sub>15</sub>H<sub>11</sub>N<sub>2</sub>S)<sub>2</sub>(OH<sub>2</sub>)<sub>2</sub>]∙2H<sub>2</sub>O (1∙2H<sub>2</sub>O), has been synthesized upon reaction of cobalt chloride hexahydrate (Co(Cl)<sub>2</sub>∙6H<sub>2</sub>O) with 3-methyl-1-Phenyl-4-(2-thienoyl)-pyrazol-5-one (referred as HL) in ethanol at room temperature. Single crystal X-ray diffraction (XRD), spectroscopic methods, and microelemental analyses were used to characterize 1∙2H<sub>2</sub>O. Compound 1∙2H<sub>2</sub>O crystallizes in the orthorhombic crystal system with a Pbca space group and with the cobalt atom being pseudo-octahedral coordinated. The broth microdilution technique was used to screen the free ligand (HL) and the complex (1∙2H<sub>2</sub>O) for antimicrobial activities. HL has a low activity (MIC > 100 μg/mL) on all microorganisms, whereas compound 1∙2H<sub>2</sub>O displayed moderate activity (10 ∙2H<sub>2</sub>O exhibited bactericidal and fungicidal activity respectively on all the bacteria and yeasts tested. These findings reveal that the antimicrobial activity of HL was enhanced upon coordination to Co(II) ion against all microorganisms (bacteria and fungus).展开更多
New cobalt(II) complex, [Co(O<sub>2</sub>C<sub>15</sub>H<sub>11</sub>N<sub>2</sub>S)<sub>2</sub>(OH<sub>2</sub>)<sub>2</sub>]∙2H<s...New cobalt(II) complex, [Co(O<sub>2</sub>C<sub>15</sub>H<sub>11</sub>N<sub>2</sub>S)<sub>2</sub>(OH<sub>2</sub>)<sub>2</sub>]∙2H<sub>2</sub>O (1∙2H<sub>2</sub>O), has been synthesized upon reaction of cobalt chloride hexahydrate (Co(Cl)<sub>2</sub>∙6H<sub>2</sub>O) with 3-methyl-1-Phenyl-4-(2-thienoyl)-pyrazol-5-one (referred as HL) in ethanol at room temperature. Single crystal X-ray diffraction (XRD), spectroscopic methods, and microelemental analyses were used to characterize 1∙2H<sub>2</sub>O. Compound 1∙2H<sub>2</sub>O crystallizes in the orthorhombic crystal system with a Pbca space group and with the cobalt atom being pseudo-octahedral coordinated. The broth microdilution technique was used to screen the free ligand (HL) and the complex (1∙2H<sub>2</sub>O) for antimicrobial activities. HL has a low activity (MIC > 100 μg/mL) on all microorganisms, whereas compound 1∙2H<sub>2</sub>O displayed moderate activity (10 ∙2H<sub>2</sub>O exhibited bactericidal and fungicidal activity respectively on all the bacteria and yeasts tested. These findings reveal that the antimicrobial activity of HL was enhanced upon coordination to Co(II) ion against all microorganisms (bacteria and fungus).展开更多
To explore pharmaceutical actinobacteria from salty environments in Siberia,8 soil samples were collected from different depths of Gudzhirganskoe saline lake,the Republic of Buryatia,Russia.Totally,635 actinobacterial...To explore pharmaceutical actinobacteria from salty environments in Siberia,8 soil samples were collected from different depths of Gudzhirganskoe saline lake,the Republic of Buryatia,Russia.Totally,635 actinobacterial strains affiliated with 21 genera in 12 families of 7 orders were obtained by culture-dependent approaches.The predominant genus was Streptomyces(74.5%),followed by Microbacterium(4.9%),Agromyces(3.5%),Nocardiopsis(3.0%),and Kitasatospora(2.5%).Seven strains showed relatively low 16 S rRNA similarities(<98.65%)with validly described species.Seventy-seven strains were selected as representatives to evaluate their antimicrobial activities and underlying mechanisms by paper-disk diffusion method and a double fluorescent protein reporter system(pDualrep 2),respectively.Streptomyces sp.S 6 b 3-1 was highlighted due to its strong inhibitory activities against Gram-positive bacteria and underlying antibacterial mechanism by inducing the SOS response in the reporter system.LG-1,(R)-6-[1-(benzoyloxy)ethyl]-phenazine-1-carboxylic acid,an analogue of saphenamycin was finally isolated from the culture broth of Streptomyces strain.This study preliminarily explored the actinobacterial diversity of soil samples collected in the highly alkaline and saline lake Gudzhirganskoe by culture-dependent approach and their capacity to produce antibiotics for the first time,which revealed that it deserves to make more efforts to discover new actinobacterial species and potential new antibiotics from the saline lake in Eastern Siberia.展开更多
With the emergence and spread of antimicrobial resistance(AMR)it becomes pertinent to search for an antimicrobial alternative to cater for the imminent need to control total drug-resistant(TDR)and multiple-drug-resist...With the emergence and spread of antimicrobial resistance(AMR)it becomes pertinent to search for an antimicrobial alternative to cater for the imminent need to control total drug-resistant(TDR)and multiple-drug-resistant(MDR)infections.Antimicrobial peptides(AMPs)have shown some promise and this study was designed to evaluate antimicrobial activity of Moricin(a naturally produced AMP by silkworm,Bombyx mori larvae)against 276 microbial strains of 83 species.Only two(Erwinia amylovora 1,Hafnia alvei 1)strains were classified as susceptible to Moricin at a concentration≤8μg/mL.If susceptibility criteria were set at MIC equivalent to≤128μg/mL then Moricin inhibited 17 strains.All of the Bacillus species strains and majority of the strains of Acinetobacter,Aeromonas,Enterococcus,Erwinia,Raoultella,and Serratia species were significantly(p<0.05)more often resistant(MIC>512μg/mL)to Moricin than strains belonging to Alacligenes,Bacillus,Escherichia,Klebsiella,Pantoea,Pasteurella,Salmonella,Staphylococcus and Streptococcus species.Susceptibility of different bacteria not only varied significantly to Moricin but also to most of the commonly used antibiotics.The susceptibility of microbes not only affected by their type but also by their source of origin.The study concluded that Moricin has a wide spectrum but limited potential to inhibit clinically important microbial strains belonging to different species and genera.展开更多
One novel spiro-compound(C_(26)H_(21)NO_3) has been synthesized and characterized by means of NMR spectroscopy,elemental analyses and X-ray diffraction. The single crystal belongs to the monoclinic system,space group ...One novel spiro-compound(C_(26)H_(21)NO_3) has been synthesized and characterized by means of NMR spectroscopy,elemental analyses and X-ray diffraction. The single crystal belongs to the monoclinic system,space group P21/c with a = 8.8039(7),b = 24.123(2),c = 10.0751(9) ?,β = 108.403(3)°,M3r = 395.44,V = 2030.3(3) ?~3,Z = 4,D_c = 1.294 g/cm,F(000) = 832.0,μ = 0.085 mm^(-1),R = 0.0801 and wR = 0.2228. The title compound shows good activities against Micrococcus tetragenus,Bacillus cereus,Bacillus subtilis,Staphylococcus aureus,S.albus and Escherichia coli.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 and t...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
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 Sonne...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
Increasing amounts of antibiotic resistant bacteria have been an emergency problem. Antimicrobial peptides are promising antibiotic alternatives for broad-spectrum antimicrobial activity and nearly no drug resistance....Increasing amounts of antibiotic resistant bacteria have been an emergency problem. Antimicrobial peptides are promising antibiotic alternatives for broad-spectrum antimicrobial activity and nearly no drug resistance. Natto peptide was a new antimicrobial peptide which consisted of 45 amino acids. In this study, to improve the antimicrobial activity of Natto peptide, three repeats of encoding sequences were synthesized and cloned into a pET28 a(+) expression vector, and expressed in Escherichia coli as a soluble protein. Unexpectedly, the purified 3×Natto peptide exhibited antimicrobial activity against Listeria monocytogenes(50 μg/ml) and Salmonella enteriditis(30 μg/ml). Furthermore, the antibacterial spectrum of 3×Natto peptide was not affected by temperature, pH value and proteinase digestion. Taken together, this was the first study proving that 3×Natto peptide could be produced in E. coli as a kind of water dissolve protein, and has great potential for commercial application in the future.展开更多
Currently, the food industry, including the meat industry, is paying close attention to the use of natural additives as preservatives. From ancient times, the plants are used to treat various diseases, to produce perf...Currently, the food industry, including the meat industry, is paying close attention to the use of natural additives as preservatives. From ancient times, the plants are used to treat various diseases, to produce perfumes and as ingredients to improve the taste in food. This paper presents a bibliographic and experimental study of the antioxidant and microbial properties of basil, thyme and tarragon. International scientific papers on the use of these plants in the food industry, including the meat industry, are targeted. The role of basil, thyme and tarragon in the manufacture of functional and stable products in storage is mentioned. Percentage decrease in <i>Salmonella Abony</i> growth under the influence of basil constituted 84.4%, thyme 61.6% and tarragon 76.8% after 48 hours of action and respectively 97.2%, 90.2% and 95.3% after 72 hours of action. The interdependence between the percentage reduction of S. Abony infestation and the concentration of basil, mushrooms and tarragon was respectively: basil (R<sup>2</sup> = 0.7725 … 0.7916), thyme (R<sup>2</sup> = 0.7733 … 0.7768), tarragon (R<sup>2</sup> = 0.7689 … 0.8137).展开更多
Objective: To evaluate the in vitro antimicrobial property of three different partitioned extracts(petroleum ether, ethanol and water) prepared from some fungal mycelia.Methods: Seven fungal mycelia were prepared, ini...Objective: To evaluate the in vitro antimicrobial property of three different partitioned extracts(petroleum ether, ethanol and water) prepared from some fungal mycelia.Methods: Seven fungal mycelia were prepared, initially extracted with acidified ethanol(0.2 mol/L HCl in 80% ethanol), yielding the raw crude extracts. The obtained extracts were then further partitioned with petroleum ether(F1), ethanol(F2) and water(F3). All the fractions were tested for antimicrobial activity using the disc diffusion assay.Results: Our data showed that all the fractions could inhibit the testing bacteria.However, the inhibitory activity was found to be dependent on(i) the fungal strains used;(ii) the solvent extracted; and(iii) the testing bacteria assayed. In general, the ethanolic extracts(F2) derived from all fungi displayed highest inhibitory activity against the testing bacteria except for Chaetomium sp.Conclusions: The findings of the present study concluded that the extracts prepared from the fungal mycelia had the bioactive compounds with antibacterial property. This study is a pioneering work and further study should be carried out for development of the new drug leads.展开更多
In this study,we used citric acid(CA)as a crosslinking agent,mixed with polyhexamethylene biguanide,to perform a pad-dry-cure treatment on wool fabrics to study its antimicrobial effects and physical properties.
Undenicylic acid(10:1)is known as an antifungal agent and an active ingredient of many topical medicines[1–6].The present research investigates the preparation of aliphatic esters of 10-undecylic acid with butanol an...Undenicylic acid(10:1)is known as an antifungal agent and an active ingredient of many topical medicines[1–6].The present research investigates the preparation of aliphatic esters of 10-undecylic acid with butanol and i-amyl alcohol by the conventional and ultrasound-assisted syntheses as well as the structural elucidation of the resulting compounds,by FTIR and NMR spectroscopy.The antimicrobial properties of the obtained 10-undecylenic esters were tested against Gram-positive bacteria(Staphylococcus aureus;Enterococcus faecalis;Listeria monocytogenes),Gram-negative bacteria(Escherichia coli;Salmonella sp.)and filamentous fungi(Penicillium sp.;Aspergillus niger;Fusarium moniliforme)using the conventional agar-well diffusion assay.The results demonstrated that all esters had insignificant antibacterial activity.i-Amyl-10-undecylenate and t-butyl-10-undecylenate showed activity against both Gram-positive and Gram-negative bacteria,while i-butyl-10-undecylenate and n-butyl-10-undecylenate were effective only against Gram-positive bacteria tested.In contrast,all 10-undecylenic esters demonstrated high antifungal activity,which was most pronounced in i-Amyl-10-undecylenate.Therefore,the obtained products can be successfully used as promising antifungal agents for various pharmaceutical formulations as well as biocontrol means against plant pathogens.展开更多
The study aimed to evaluate the endophytic fungi isolated from <em>Cocos nucifera</em> (L.) cotyledon for their possible antimicrobial activity. A total of twelve endophytic fungal species were successfull...The study aimed to evaluate the endophytic fungi isolated from <em>Cocos nucifera</em> (L.) cotyledon for their possible antimicrobial activity. A total of twelve endophytic fungal species were successfully isolated, from which five were selected and presumptively identified, including <em>Aspergillus niger</em>, <em>Raffaelea sp.</em>, <em>Aspergillus flavus</em>, <em>Cladosporium sp.</em> and <em>Pseudallescheria spp.</em> based on their macro and microscopic characters. The agar blocks of actively growing pure culture were assessed for antibacterial activity against five human pathogenic bacterial and fungal strains: <em>Escherichia coli</em> (BIOTECH 1634), <em>Bacillus subtilis</em> (BIOTECH 1697), <em>Staphylococcus aureus</em> (BIOTECH 1592), <em>Serratia marcescens</em> (BIOTECH 1748), and <em>Candida tropicalis</em> (BIOTECH 2085). Among the selected five endophytic used for antimicrobial activity screening, the <em>Raffaelea sp.</em> (CN-EF 2) has shown a high zone of inhibition of 11 mm against <em>Bacillus subtilis</em>, 18 mm against <em>Escherichia coli</em>, 15 mm against <em>Staphylococcus aureus</em>, and 11 mm against <em>Candida tropicalis</em>. Correspondingly, <em>Aspergillus niger</em> (CN-EF 1) has shown a zone of inhibition of 16 mm against <em>C. tropicalis</em>. The endophytic fungus <em>Raffaelea sp.</em> was effective against all test organisms except for <em>Serratia marcescens</em>, while <em>Aspergillus niger</em> was only effective for pathogenic fungi <em>C. albicans</em>. Hence, further in-depth studies of the isolated endophytic fungi are needed to determine the mechanisms behind the endophytes’ inhibitory effects.展开更多
Propolis is a resinous natural product,produced by bees(Apis mellifera),from vegetable parts and plant secretions.Propolis’samples A,B,C and D were extracted with phosphate buffer saline(PBS)or with 70%EtOH at pH val...Propolis is a resinous natural product,produced by bees(Apis mellifera),from vegetable parts and plant secretions.Propolis’samples A,B,C and D were extracted with phosphate buffer saline(PBS)or with 70%EtOH at pH values 8.0,7.2 and 6.4 followed by:(1)reverse-phase high-performance liquid chromatography(RP-HPLC)on Purospher®Star RP-18 column,the quantity of caffeic acid,chrysin,pinocembrin and galangin was determined;(2)determination of total flavonoids in both extracts;(3)antimicrobial tests of both extracts against(a)Gram-positive bacteria:methicillin-resistant Staphylococcus aureus(MRSA),St.aureus,Streptococcus pyogenes,Str.agalactiae,(b)Gram-negative bacteria:Escherichia coli,Pseudomonas aeruginosa,Proteus mirabilis,Acinetobacter baumanii and(c)yeast:Candida albicans.The antimicrobial activity of propolis’PBS extracts against Gram-positive bacteria shows the lowest minimal inhibitory concentration(MIC,mg/mL)at pH 8.0 in sample C,followed by A,B and D.In sample C,MICs at pH 8.0 were 0.007(Str.agalactiae),0.015(MRSA),0.015(Str.pyogenes)and 0.007(St.aureus).The polyphenol content of sample C is:flavonoid content 5.47±0.62 mg/mL,caffeic acid 1.33±0.92 mg/mL,chrysin 41.02±4.22μg/mL,pinocembrin 2.93±0.33 mg/mL and galangin 41.87±4.23 mg/mL.PBS extracts against Gram-negative bacteria show the lowest MIC(mg/mL)at pH 8.0 in sample D,followed by B,C and A.In sample D,MICs at pH 8.0 were 0.003(Acin.baumanii,Pr.mirabilis,Ps.aeruginosa)and 0.007(E.coli).Polyphenol content of sample D is:flavonoids 8.28±0.92 mg/mL,caffeic acid 3.56±0.32 mg/mL,chrysin 677.42±68.42μg/mL,pinocembrin 146.49±13.89 mg/mL and galangin 59.81±5.86 mg/mL.The strongest anti C.albicans activity,with the lowest MIC(mg/mL),at pH 8.0 was in the sample C,followed by samples D,A and B.In sample C,the MIC at pH 8.0 is 0.001(PBS extract).The antimicrobial activities of selected propolis samples correlate with their polyphenol content,more precisely,flavonoid,caffeic acid,chrysin,pinocembrin and galangin content.展开更多
Yellow Wasp Polistes flavus venom toxins were isolated and purified on a Sepharose CL-6B 200 column. Purified proteins were investigated for its antibacterial and antifungal activity against 13 infectious microbial pa...Yellow Wasp Polistes flavus venom toxins were isolated and purified on a Sepharose CL-6B 200 column. Purified proteins were investigated for its antibacterial and antifungal activity against 13 infectious microbial pathogens. Paper disc diffusion and serial micro-dilution assays were performed for the determination of inhibition zone (DIZ) diameters and minimal inhibitory concentration, respectively. Triton X-100 (0.1%) proved to be a good solubilizing agent for toxin/proteins. Higher protein solubilization was observed in the supernatant than in the residue, except TCA (tri-chloroacetic acid). The elution pattern of purified and homogenized sting glands exhibited two major peaks at 280 nm in fraction No. 41 - 61 and 81 - 101. The total yield of protein was 69.21% and specific activity was determined in each fraction. Molecular weights in protein fractions were ranging from 6 - 70 kD. MIC (Minimum Inhibitory Concentration) values were 12.3 μg/ml against K. pneumonia 12.3 μg/ml against E. coli and L. acidophilus, 24.6 μg/ml against B. cereus;49.24 μg/ml against S. aureus and M. luteus. By agar disc diffusion method, the diameter of inhibition zones in mm in presence of yellow wasp toxins is at a concentration range of 98.56 - 6.9 μg/ml E. coli 18.36 ± 0.14, Bacillus cereus 14.566 ± 0.21, L. acidophilus 18.10 ± 0.21, Micrococcus luteus 18.76 ± 0.19, S. aeurus 17.36 ± 0.43, Klebsiella pneuminiae 19.56 ± 0.21, Salmonella typhi 19.96 ± 0.31, Vibrio cholera 21.83 ± 0.22, Pseudomonas aeruginosa 22.90 ± 0.09, Aspergillus niger 21.66 ± 0.16, Candida albicans 23.33 ± 0.26, Rhizopus stolonifer 24.96 ± 0.16 respectively. The antibacterial and antifungal activity of venom toxin may be due to action on cell membrane, its destruction and cell lysis. The wasp toxins may be used as strong biological agents to control microbes.展开更多
Essential oils are secondary metabolites whose biological properties have been studied with emphasis on antimicrobial activity. Hyptis carpinifolia Benth (Rosmaninho) is used in folk medicine in the fight against cold...Essential oils are secondary metabolites whose biological properties have been studied with emphasis on antimicrobial activity. Hyptis carpinifolia Benth (Rosmaninho) is used in folk medicine in the fight against colds and rheumatism. The objective of this study was to evaluate the antimicrobial activity of the essential oil from H. carpinifolia. The essential oil was extracted by hydrodistillation using a modified Clevenger apparatus. The biological activity was determined using the Agar Cavity Diffusion technique to evaluate the effect of concentrations of 500, 250, 125, 62.5, 31.25, 15.62, 7.81 and 3.9 μg·mL-1 on the bacteria Escherichia coli, Listeria monocytogenes, Salmonella Choleraesuis, Staphylococcus aureus and Pseudomonas aeruginosa. The fungicidal potential was evaluated by the method of dilution in agar, and the percentage inhibition of mycelial growth of Alternaria alternata, Botrytis cinerea and Fusarium oxysporum was evaluated. The dilutions tested were 1000, 750, 500, 250 and 100 μL·L-1. The minimum inhibitory concentrations (MIC) of the essential oil for L. monocytogenes, S. aureus and E. coli were 31.25;15.62 and 62.5 μg·mL-1, respectively. The MIC was 500 μg·mL-1 for Salmonella Choleraesuis and P. aeruginosa. The percentage inhibitions of mycelial growth of B. cinerea and A. alternate were 67% and 33%, respectively, at the dilution of 750 μL·L-1. The essential oil inhibited about 48% of the mycelial growth of F. oxysporum, at the dilution of 1000 μL·L-1. The essential oil of H. carpinifolia presented biological activity against all the microorganisms evaluated.展开更多
Bacterial infection is considered to be one of the most critical health issues of the world. It is essential to overcome this problem by the development of new drugs. Marine organisms as corals, sponges, seaweeds, and...Bacterial infection is considered to be one of the most critical health issues of the world. It is essential to overcome this problem by the development of new drugs. Marine organisms as corals, sponges, seaweeds, and other are an incredible source of novel pharmacologically active compounds. Herein, the antimicrobial activity (extract/fractions) of the invasive stony coralTubastraea coccinea was evaluated by the disk diffusion method against 21 microbial strains (ATCC and clinical strains). Micro broth dilution was used to determinate the MIC of the fractions that showed antimicrobial activity by the disk diffusion method. Bioautography assay was also performed. Our results showed that the n-butanol (BF) and aqueous fractions (AF) showed activity against ATCC strains Staphylococcus aureus (MIC 31.25 and 250 μg/mL),Salmonella typhimurium (MIC 125 and 500 μg/mL), Escherichia coli (MIC 62.5 and 500 μg/mL) and Pseudomonas aeruginosa (MIC 62.5 and 500 μg/mL), respectively. Moreover, BF fraction was also effective against the clinical strains S. aureus(MIC 62.5 μg/mL), Klebsiella pneumoniae Carbapenemase—KPC (MIC 125 μg/mL), Methicillin-Resistant Staphylococcus aureus—MRSA (MIC 125 μg/mL) and Vancomycin-Resistant Enterococcus faecalis—VRE (MIC 62.5 μg/mL). The ratio MBC/MIC reinforces the bactericidal profile of BF fraction. The bioautography assay of BF fraction showed the presence of antimicrobial components at R<sub>f</sub>0.55.展开更多
Citrus aurantifolia, the family Rutaceae, which consists of 150 genera and 900 species, is gaining grounds as important source for treatment in complementary medicine, and commonly called limone. Chloroform, methanol ...Citrus aurantifolia, the family Rutaceae, which consists of 150 genera and 900 species, is gaining grounds as important source for treatment in complementary medicine, and commonly called limone. Chloroform, methanol and ethanol extract exhibited significant antimicrobial activity and highlighted the biological monitoring of activity from the methanol extract of seeds. Phytochemical screening of the diethyl ether, methanol and aqueous extracts of seeds confirmed the presence of alkaloids, saponins, sterols and triterpenes, carotenoids, coumarins, tannins and carbohydrates. Chloroform extract was fractionated by sing liquid solid column chromatographic technique and column fractions eluted with chloroform and methanol. The antibacterial secondary metabolites were achieved by fractionation of the active. The seed extracts were monitored analytically by TLC preparative and some chemical analyses of seeds have been done such as determination of ash, nitrogen, protein content.展开更多
In this paper, three complexes with 8-hydroxyquinoline (8-HQ) were synthesized, their spectral analysis was performed and the antimicrobial effect was examined <em>in vitro</em>. The stoichiometric ratio o...In this paper, three complexes with 8-hydroxyquinoline (8-HQ) were synthesized, their spectral analysis was performed and the antimicrobial effect was examined <em>in vitro</em>. The stoichiometric ratio of the complex was determined conductometrically and spectrophotometrically. FTIR and UV/VIS spectroscopy were used for structural characterization. Antimicrobial activity was examined by diffusion technique on selected gram-positive and gram-negative bacteria, and<em> C. albicans</em>. Square planar and octahedral geometry complexes were synthesized by mixing in a molar ratio of 1:2 (M:L). Based on the spectral data, it is concluded that both oxygen and nitrogen atoms from 8-HQ are involved in the formation of the complex. The antimicrobial activity of the complexes is high, with zones of inhibition in the range of 15 - 28 mm. 8-HQ was shown to have a significantly higher ability to inhibit the growth of the tested microorganisms.展开更多
文摘New cobalt(II) complex, [Co(O<sub>2</sub>C<sub>15</sub>H<sub>11</sub>N<sub>2</sub>S)<sub>2</sub>(OH<sub>2</sub>)<sub>2</sub>]∙2H<sub>2</sub>O (1∙2H<sub>2</sub>O), has been synthesized upon reaction of cobalt chloride hexahydrate (Co(Cl)<sub>2</sub>∙6H<sub>2</sub>O) with 3-methyl-1-Phenyl-4-(2-thienoyl)-pyrazol-5-one (referred as HL) in ethanol at room temperature. Single crystal X-ray diffraction (XRD), spectroscopic methods, and microelemental analyses were used to characterize 1∙2H<sub>2</sub>O. Compound 1∙2H<sub>2</sub>O crystallizes in the orthorhombic crystal system with a Pbca space group and with the cobalt atom being pseudo-octahedral coordinated. The broth microdilution technique was used to screen the free ligand (HL) and the complex (1∙2H<sub>2</sub>O) for antimicrobial activities. HL has a low activity (MIC > 100 μg/mL) on all microorganisms, whereas compound 1∙2H<sub>2</sub>O displayed moderate activity (10 ∙2H<sub>2</sub>O exhibited bactericidal and fungicidal activity respectively on all the bacteria and yeasts tested. These findings reveal that the antimicrobial activity of HL was enhanced upon coordination to Co(II) ion against all microorganisms (bacteria and fungus).
文摘New cobalt(II) complex, [Co(O<sub>2</sub>C<sub>15</sub>H<sub>11</sub>N<sub>2</sub>S)<sub>2</sub>(OH<sub>2</sub>)<sub>2</sub>]∙2H<sub>2</sub>O (1∙2H<sub>2</sub>O), has been synthesized upon reaction of cobalt chloride hexahydrate (Co(Cl)<sub>2</sub>∙6H<sub>2</sub>O) with 3-methyl-1-Phenyl-4-(2-thienoyl)-pyrazol-5-one (referred as HL) in ethanol at room temperature. Single crystal X-ray diffraction (XRD), spectroscopic methods, and microelemental analyses were used to characterize 1∙2H<sub>2</sub>O. Compound 1∙2H<sub>2</sub>O crystallizes in the orthorhombic crystal system with a Pbca space group and with the cobalt atom being pseudo-octahedral coordinated. The broth microdilution technique was used to screen the free ligand (HL) and the complex (1∙2H<sub>2</sub>O) for antimicrobial activities. HL has a low activity (MIC > 100 μg/mL) on all microorganisms, whereas compound 1∙2H<sub>2</sub>O displayed moderate activity (10 ∙2H<sub>2</sub>O exhibited bactericidal and fungicidal activity respectively on all the bacteria and yeasts tested. These findings reveal that the antimicrobial activity of HL was enhanced upon coordination to Co(II) ion against all microorganisms (bacteria and fungus).
基金Supported by the CAMS Innovation Fund for Medical Sciences(No.CIFMS 2021-I 2 M-1-028)the Beijing Natural Science Foundation(No.7222256)+5 种基金the National Natural Science Foundation of China(No.82011530051)the Kunlun Talented People,High-end Innovation and Entrepreneurship talents Plan,Qinghai Province,China,for Chenghang SUN,the Talent Training Project of Basic Research Fund of Heilongjiang Department of Education Item to Chunmei XUE(No.2020-KYYWF-0238)the Sino-Hungarian Bilateral S&T Cooperation Projects from 2019 to 2020(Chinese Project:8-11)partly supported by the Russian Foundation for Basic Research(Nos.NCFS-RFBR 20-54-53014,18-44-030021 r_а)the Russian Science Foundation(No.20-74-10031)partially within the framework of the State Assignment(No.121030100229-1)for Institute of General and Experimental Biology,Siberian Branch,Russian Academy of Sciences。
文摘To explore pharmaceutical actinobacteria from salty environments in Siberia,8 soil samples were collected from different depths of Gudzhirganskoe saline lake,the Republic of Buryatia,Russia.Totally,635 actinobacterial strains affiliated with 21 genera in 12 families of 7 orders were obtained by culture-dependent approaches.The predominant genus was Streptomyces(74.5%),followed by Microbacterium(4.9%),Agromyces(3.5%),Nocardiopsis(3.0%),and Kitasatospora(2.5%).Seven strains showed relatively low 16 S rRNA similarities(<98.65%)with validly described species.Seventy-seven strains were selected as representatives to evaluate their antimicrobial activities and underlying mechanisms by paper-disk diffusion method and a double fluorescent protein reporter system(pDualrep 2),respectively.Streptomyces sp.S 6 b 3-1 was highlighted due to its strong inhibitory activities against Gram-positive bacteria and underlying antibacterial mechanism by inducing the SOS response in the reporter system.LG-1,(R)-6-[1-(benzoyloxy)ethyl]-phenazine-1-carboxylic acid,an analogue of saphenamycin was finally isolated from the culture broth of Streptomyces strain.This study preliminarily explored the actinobacterial diversity of soil samples collected in the highly alkaline and saline lake Gudzhirganskoe by culture-dependent approach and their capacity to produce antibiotics for the first time,which revealed that it deserves to make more efforts to discover new actinobacterial species and potential new antibiotics from the saline lake in Eastern Siberia.
基金The research work was supported by grants received from CAAST-ACLH(No.NAHEP/CAAST/2018-19)of ICAR-World Bank-funded National Agricultural Higher Education Project(NAHEP).
文摘With the emergence and spread of antimicrobial resistance(AMR)it becomes pertinent to search for an antimicrobial alternative to cater for the imminent need to control total drug-resistant(TDR)and multiple-drug-resistant(MDR)infections.Antimicrobial peptides(AMPs)have shown some promise and this study was designed to evaluate antimicrobial activity of Moricin(a naturally produced AMP by silkworm,Bombyx mori larvae)against 276 microbial strains of 83 species.Only two(Erwinia amylovora 1,Hafnia alvei 1)strains were classified as susceptible to Moricin at a concentration≤8μg/mL.If susceptibility criteria were set at MIC equivalent to≤128μg/mL then Moricin inhibited 17 strains.All of the Bacillus species strains and majority of the strains of Acinetobacter,Aeromonas,Enterococcus,Erwinia,Raoultella,and Serratia species were significantly(p<0.05)more often resistant(MIC>512μg/mL)to Moricin than strains belonging to Alacligenes,Bacillus,Escherichia,Klebsiella,Pantoea,Pasteurella,Salmonella,Staphylococcus and Streptococcus species.Susceptibility of different bacteria not only varied significantly to Moricin but also to most of the commonly used antibiotics.The susceptibility of microbes not only affected by their type but also by their source of origin.The study concluded that Moricin has a wide spectrum but limited potential to inhibit clinically important microbial strains belonging to different species and genera.
基金Project supported by the Natural Science Foundation of Hainan Province(No.20162033)the Cultivation Research Foundation of Hainan Medical University(HY2015-02)
文摘One novel spiro-compound(C_(26)H_(21)NO_3) has been synthesized and characterized by means of NMR spectroscopy,elemental analyses and X-ray diffraction. The single crystal belongs to the monoclinic system,space group P21/c with a = 8.8039(7),b = 24.123(2),c = 10.0751(9) ?,β = 108.403(3)°,M3r = 395.44,V = 2030.3(3) ?~3,Z = 4,D_c = 1.294 g/cm,F(000) = 832.0,μ = 0.085 mm^(-1),R = 0.0801 and wR = 0.2228. The title compound shows good activities against Micrococcus tetragenus,Bacillus cereus,Bacillus subtilis,Staphylococcus aureus,S.albus and Escherichia coli.
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.
基金Supported by Shandong Provincial Natural Science Foundation(ZR2018PC010)the Doctor Foundation of Binzhou University(2018Y09)Natural Science Program of Binzhou University(BZXYG1811)
文摘Increasing amounts of antibiotic resistant bacteria have been an emergency problem. Antimicrobial peptides are promising antibiotic alternatives for broad-spectrum antimicrobial activity and nearly no drug resistance. Natto peptide was a new antimicrobial peptide which consisted of 45 amino acids. In this study, to improve the antimicrobial activity of Natto peptide, three repeats of encoding sequences were synthesized and cloned into a pET28 a(+) expression vector, and expressed in Escherichia coli as a soluble protein. Unexpectedly, the purified 3×Natto peptide exhibited antimicrobial activity against Listeria monocytogenes(50 μg/ml) and Salmonella enteriditis(30 μg/ml). Furthermore, the antibacterial spectrum of 3×Natto peptide was not affected by temperature, pH value and proteinase digestion. Taken together, this was the first study proving that 3×Natto peptide could be produced in E. coli as a kind of water dissolve protein, and has great potential for commercial application in the future.
文摘Currently, the food industry, including the meat industry, is paying close attention to the use of natural additives as preservatives. From ancient times, the plants are used to treat various diseases, to produce perfumes and as ingredients to improve the taste in food. This paper presents a bibliographic and experimental study of the antioxidant and microbial properties of basil, thyme and tarragon. International scientific papers on the use of these plants in the food industry, including the meat industry, are targeted. The role of basil, thyme and tarragon in the manufacture of functional and stable products in storage is mentioned. Percentage decrease in <i>Salmonella Abony</i> growth under the influence of basil constituted 84.4%, thyme 61.6% and tarragon 76.8% after 48 hours of action and respectively 97.2%, 90.2% and 95.3% after 72 hours of action. The interdependence between the percentage reduction of S. Abony infestation and the concentration of basil, mushrooms and tarragon was respectively: basil (R<sup>2</sup> = 0.7725 … 0.7916), thyme (R<sup>2</sup> = 0.7733 … 0.7768), tarragon (R<sup>2</sup> = 0.7689 … 0.8137).
基金Supported by“Operational Program Prague–Competitiveness”(CZ.2.16/3.1.00/24503)the“National Program of Sustainability I”-NPU I(LO1601-No.:MSMT-43760/2015)from the University of Chemistry and Technology,Czech Republic
文摘Objective: To evaluate the in vitro antimicrobial property of three different partitioned extracts(petroleum ether, ethanol and water) prepared from some fungal mycelia.Methods: Seven fungal mycelia were prepared, initially extracted with acidified ethanol(0.2 mol/L HCl in 80% ethanol), yielding the raw crude extracts. The obtained extracts were then further partitioned with petroleum ether(F1), ethanol(F2) and water(F3). All the fractions were tested for antimicrobial activity using the disc diffusion assay.Results: Our data showed that all the fractions could inhibit the testing bacteria.However, the inhibitory activity was found to be dependent on(i) the fungal strains used;(ii) the solvent extracted; and(iii) the testing bacteria assayed. In general, the ethanolic extracts(F2) derived from all fungi displayed highest inhibitory activity against the testing bacteria except for Chaetomium sp.Conclusions: The findings of the present study concluded that the extracts prepared from the fungal mycelia had the bioactive compounds with antibacterial property. This study is a pioneering work and further study should be carried out for development of the new drug leads.
文摘In this study,we used citric acid(CA)as a crosslinking agent,mixed with polyhexamethylene biguanide,to perform a pad-dry-cure treatment on wool fabrics to study its antimicrobial effects and physical properties.
基金supported by Fund Science Contract No 1805С,Technical University of Gabrovo,Bulgaria.
文摘Undenicylic acid(10:1)is known as an antifungal agent and an active ingredient of many topical medicines[1–6].The present research investigates the preparation of aliphatic esters of 10-undecylic acid with butanol and i-amyl alcohol by the conventional and ultrasound-assisted syntheses as well as the structural elucidation of the resulting compounds,by FTIR and NMR spectroscopy.The antimicrobial properties of the obtained 10-undecylenic esters were tested against Gram-positive bacteria(Staphylococcus aureus;Enterococcus faecalis;Listeria monocytogenes),Gram-negative bacteria(Escherichia coli;Salmonella sp.)and filamentous fungi(Penicillium sp.;Aspergillus niger;Fusarium moniliforme)using the conventional agar-well diffusion assay.The results demonstrated that all esters had insignificant antibacterial activity.i-Amyl-10-undecylenate and t-butyl-10-undecylenate showed activity against both Gram-positive and Gram-negative bacteria,while i-butyl-10-undecylenate and n-butyl-10-undecylenate were effective only against Gram-positive bacteria tested.In contrast,all 10-undecylenic esters demonstrated high antifungal activity,which was most pronounced in i-Amyl-10-undecylenate.Therefore,the obtained products can be successfully used as promising antifungal agents for various pharmaceutical formulations as well as biocontrol means against plant pathogens.
文摘The study aimed to evaluate the endophytic fungi isolated from <em>Cocos nucifera</em> (L.) cotyledon for their possible antimicrobial activity. A total of twelve endophytic fungal species were successfully isolated, from which five were selected and presumptively identified, including <em>Aspergillus niger</em>, <em>Raffaelea sp.</em>, <em>Aspergillus flavus</em>, <em>Cladosporium sp.</em> and <em>Pseudallescheria spp.</em> based on their macro and microscopic characters. The agar blocks of actively growing pure culture were assessed for antibacterial activity against five human pathogenic bacterial and fungal strains: <em>Escherichia coli</em> (BIOTECH 1634), <em>Bacillus subtilis</em> (BIOTECH 1697), <em>Staphylococcus aureus</em> (BIOTECH 1592), <em>Serratia marcescens</em> (BIOTECH 1748), and <em>Candida tropicalis</em> (BIOTECH 2085). Among the selected five endophytic used for antimicrobial activity screening, the <em>Raffaelea sp.</em> (CN-EF 2) has shown a high zone of inhibition of 11 mm against <em>Bacillus subtilis</em>, 18 mm against <em>Escherichia coli</em>, 15 mm against <em>Staphylococcus aureus</em>, and 11 mm against <em>Candida tropicalis</em>. Correspondingly, <em>Aspergillus niger</em> (CN-EF 1) has shown a zone of inhibition of 16 mm against <em>C. tropicalis</em>. The endophytic fungus <em>Raffaelea sp.</em> was effective against all test organisms except for <em>Serratia marcescens</em>, while <em>Aspergillus niger</em> was only effective for pathogenic fungi <em>C. albicans</em>. Hence, further in-depth studies of the isolated endophytic fungi are needed to determine the mechanisms behind the endophytes’ inhibitory effects.
基金the frame of Croatian Institute for Experimental and Translational Oncology(CIETO)supported by IvanČermak from the Crodux-plin,Savska Opatovina,10000 Zagreb,Croatia。
文摘Propolis is a resinous natural product,produced by bees(Apis mellifera),from vegetable parts and plant secretions.Propolis’samples A,B,C and D were extracted with phosphate buffer saline(PBS)or with 70%EtOH at pH values 8.0,7.2 and 6.4 followed by:(1)reverse-phase high-performance liquid chromatography(RP-HPLC)on Purospher®Star RP-18 column,the quantity of caffeic acid,chrysin,pinocembrin and galangin was determined;(2)determination of total flavonoids in both extracts;(3)antimicrobial tests of both extracts against(a)Gram-positive bacteria:methicillin-resistant Staphylococcus aureus(MRSA),St.aureus,Streptococcus pyogenes,Str.agalactiae,(b)Gram-negative bacteria:Escherichia coli,Pseudomonas aeruginosa,Proteus mirabilis,Acinetobacter baumanii and(c)yeast:Candida albicans.The antimicrobial activity of propolis’PBS extracts against Gram-positive bacteria shows the lowest minimal inhibitory concentration(MIC,mg/mL)at pH 8.0 in sample C,followed by A,B and D.In sample C,MICs at pH 8.0 were 0.007(Str.agalactiae),0.015(MRSA),0.015(Str.pyogenes)and 0.007(St.aureus).The polyphenol content of sample C is:flavonoid content 5.47±0.62 mg/mL,caffeic acid 1.33±0.92 mg/mL,chrysin 41.02±4.22μg/mL,pinocembrin 2.93±0.33 mg/mL and galangin 41.87±4.23 mg/mL.PBS extracts against Gram-negative bacteria show the lowest MIC(mg/mL)at pH 8.0 in sample D,followed by B,C and A.In sample D,MICs at pH 8.0 were 0.003(Acin.baumanii,Pr.mirabilis,Ps.aeruginosa)and 0.007(E.coli).Polyphenol content of sample D is:flavonoids 8.28±0.92 mg/mL,caffeic acid 3.56±0.32 mg/mL,chrysin 677.42±68.42μg/mL,pinocembrin 146.49±13.89 mg/mL and galangin 59.81±5.86 mg/mL.The strongest anti C.albicans activity,with the lowest MIC(mg/mL),at pH 8.0 was in the sample C,followed by samples D,A and B.In sample C,the MIC at pH 8.0 is 0.001(PBS extract).The antimicrobial activities of selected propolis samples correlate with their polyphenol content,more precisely,flavonoid,caffeic acid,chrysin,pinocembrin and galangin content.
文摘Yellow Wasp Polistes flavus venom toxins were isolated and purified on a Sepharose CL-6B 200 column. Purified proteins were investigated for its antibacterial and antifungal activity against 13 infectious microbial pathogens. Paper disc diffusion and serial micro-dilution assays were performed for the determination of inhibition zone (DIZ) diameters and minimal inhibitory concentration, respectively. Triton X-100 (0.1%) proved to be a good solubilizing agent for toxin/proteins. Higher protein solubilization was observed in the supernatant than in the residue, except TCA (tri-chloroacetic acid). The elution pattern of purified and homogenized sting glands exhibited two major peaks at 280 nm in fraction No. 41 - 61 and 81 - 101. The total yield of protein was 69.21% and specific activity was determined in each fraction. Molecular weights in protein fractions were ranging from 6 - 70 kD. MIC (Minimum Inhibitory Concentration) values were 12.3 μg/ml against K. pneumonia 12.3 μg/ml against E. coli and L. acidophilus, 24.6 μg/ml against B. cereus;49.24 μg/ml against S. aureus and M. luteus. By agar disc diffusion method, the diameter of inhibition zones in mm in presence of yellow wasp toxins is at a concentration range of 98.56 - 6.9 μg/ml E. coli 18.36 ± 0.14, Bacillus cereus 14.566 ± 0.21, L. acidophilus 18.10 ± 0.21, Micrococcus luteus 18.76 ± 0.19, S. aeurus 17.36 ± 0.43, Klebsiella pneuminiae 19.56 ± 0.21, Salmonella typhi 19.96 ± 0.31, Vibrio cholera 21.83 ± 0.22, Pseudomonas aeruginosa 22.90 ± 0.09, Aspergillus niger 21.66 ± 0.16, Candida albicans 23.33 ± 0.26, Rhizopus stolonifer 24.96 ± 0.16 respectively. The antibacterial and antifungal activity of venom toxin may be due to action on cell membrane, its destruction and cell lysis. The wasp toxins may be used as strong biological agents to control microbes.
文摘Essential oils are secondary metabolites whose biological properties have been studied with emphasis on antimicrobial activity. Hyptis carpinifolia Benth (Rosmaninho) is used in folk medicine in the fight against colds and rheumatism. The objective of this study was to evaluate the antimicrobial activity of the essential oil from H. carpinifolia. The essential oil was extracted by hydrodistillation using a modified Clevenger apparatus. The biological activity was determined using the Agar Cavity Diffusion technique to evaluate the effect of concentrations of 500, 250, 125, 62.5, 31.25, 15.62, 7.81 and 3.9 μg·mL-1 on the bacteria Escherichia coli, Listeria monocytogenes, Salmonella Choleraesuis, Staphylococcus aureus and Pseudomonas aeruginosa. The fungicidal potential was evaluated by the method of dilution in agar, and the percentage inhibition of mycelial growth of Alternaria alternata, Botrytis cinerea and Fusarium oxysporum was evaluated. The dilutions tested were 1000, 750, 500, 250 and 100 μL·L-1. The minimum inhibitory concentrations (MIC) of the essential oil for L. monocytogenes, S. aureus and E. coli were 31.25;15.62 and 62.5 μg·mL-1, respectively. The MIC was 500 μg·mL-1 for Salmonella Choleraesuis and P. aeruginosa. The percentage inhibitions of mycelial growth of B. cinerea and A. alternate were 67% and 33%, respectively, at the dilution of 750 μL·L-1. The essential oil inhibited about 48% of the mycelial growth of F. oxysporum, at the dilution of 1000 μL·L-1. The essential oil of H. carpinifolia presented biological activity against all the microorganisms evaluated.
文摘Bacterial infection is considered to be one of the most critical health issues of the world. It is essential to overcome this problem by the development of new drugs. Marine organisms as corals, sponges, seaweeds, and other are an incredible source of novel pharmacologically active compounds. Herein, the antimicrobial activity (extract/fractions) of the invasive stony coralTubastraea coccinea was evaluated by the disk diffusion method against 21 microbial strains (ATCC and clinical strains). Micro broth dilution was used to determinate the MIC of the fractions that showed antimicrobial activity by the disk diffusion method. Bioautography assay was also performed. Our results showed that the n-butanol (BF) and aqueous fractions (AF) showed activity against ATCC strains Staphylococcus aureus (MIC 31.25 and 250 μg/mL),Salmonella typhimurium (MIC 125 and 500 μg/mL), Escherichia coli (MIC 62.5 and 500 μg/mL) and Pseudomonas aeruginosa (MIC 62.5 and 500 μg/mL), respectively. Moreover, BF fraction was also effective against the clinical strains S. aureus(MIC 62.5 μg/mL), Klebsiella pneumoniae Carbapenemase—KPC (MIC 125 μg/mL), Methicillin-Resistant Staphylococcus aureus—MRSA (MIC 125 μg/mL) and Vancomycin-Resistant Enterococcus faecalis—VRE (MIC 62.5 μg/mL). The ratio MBC/MIC reinforces the bactericidal profile of BF fraction. The bioautography assay of BF fraction showed the presence of antimicrobial components at R<sub>f</sub>0.55.
文摘Citrus aurantifolia, the family Rutaceae, which consists of 150 genera and 900 species, is gaining grounds as important source for treatment in complementary medicine, and commonly called limone. Chloroform, methanol and ethanol extract exhibited significant antimicrobial activity and highlighted the biological monitoring of activity from the methanol extract of seeds. Phytochemical screening of the diethyl ether, methanol and aqueous extracts of seeds confirmed the presence of alkaloids, saponins, sterols and triterpenes, carotenoids, coumarins, tannins and carbohydrates. Chloroform extract was fractionated by sing liquid solid column chromatographic technique and column fractions eluted with chloroform and methanol. The antibacterial secondary metabolites were achieved by fractionation of the active. The seed extracts were monitored analytically by TLC preparative and some chemical analyses of seeds have been done such as determination of ash, nitrogen, protein content.
文摘In this paper, three complexes with 8-hydroxyquinoline (8-HQ) were synthesized, their spectral analysis was performed and the antimicrobial effect was examined <em>in vitro</em>. The stoichiometric ratio of the complex was determined conductometrically and spectrophotometrically. FTIR and UV/VIS spectroscopy were used for structural characterization. Antimicrobial activity was examined by diffusion technique on selected gram-positive and gram-negative bacteria, and<em> C. albicans</em>. Square planar and octahedral geometry complexes were synthesized by mixing in a molar ratio of 1:2 (M:L). Based on the spectral data, it is concluded that both oxygen and nitrogen atoms from 8-HQ are involved in the formation of the complex. The antimicrobial activity of the complexes is high, with zones of inhibition in the range of 15 - 28 mm. 8-HQ was shown to have a significantly higher ability to inhibit the growth of the tested microorganisms.
