Objective:To investigate the antioxidant activity of marine actinobacteria.Methods:The content of total phenolics,the level of antioxidant potential by DPPH radical scavenging activity,metal chelating activity,FRAP me...Objective:To investigate the antioxidant activity of marine actinobacteria.Methods:The content of total phenolics,the level of antioxidant potential by DPPH radical scavenging activity,metal chelating activity,FRAP method,βcarotene assay and NO scavenging activity in extract were determined.Results:In all the methods the extract exhibited good scavenging activity except NO scavenging activity.The IC<sub>50</sub> values of marine actinobacteria extract on DPPH radical were found to be 41.09μg/mL.The zone of color retention was 12 mm inβ-carotene bleaching assay. DNA protective efficiency of the extracts was also studied using UV- photolysed H<sub>2</sub>O<sub>2</sub>-driven oxidative damage to pBR322.HPLC analysis identified some of the major phenolic compounds in extracts,which might he responsible for the antioxidant potential and cyto-protection.It showed a 100%cytotoxic effect in brine shrimp lethality assay within 10 mins.The novel actinobacteria was identified as Streptomyces LK-3（JF710608） through I6S rDNA Sequencing.Conclusions:The results obtained suggest that the extracts bear anti-cancer metabolites and could be considered as a potential source for anti-cancer drug development.展开更多
Objective:To assess the acaricidal activity of titanium dioxide nanoparticles(TiO_2 NPs)synthesized from flower aqueous extract of Calotropis gigantea(C.gigantea)against the larvae of Rhipicephalus(Boophilus)microplus...Objective:To assess the acaricidal activity of titanium dioxide nanoparticles(TiO_2 NPs)synthesized from flower aqueous extract of Calotropis gigantea(C.gigantea)against the larvae of Rhipicephalus(Boophilus)microplus[R.(B.)microplus]and the adult of Haemaphrysalis bispinosa(H.bispinosa).Methods:The lyophilized C.gigantea flower aqueous extract of 50 mg was added with 100 mL of TiO(OH_2)(10 mM)and magnetically stirred for 6 h.Synthesized TiO_2 NPs were characterized by X-ray diffraction(XRD).Fourier transform infrared spectroscopy(FTIR),Scanning electron microscopy(SEM),and Energy dispersive X-ray spectroscopy(EDX).The synthesised TiO_2 NPs were tested against the larvae of R(B.)microplus and adult of H.bispinosa were exposed to filter paper impregnated method.Results:XRD confirmed the crystalline nature of the nanoparticles with the mean size of 10.52 nm.The functional groups for synthesized TiO_2NPs were 1405.19,and 1053.45 cm^(-1)for-NH_2 bending,primary amines and amides and 1053.84and 1078.45 cm^(-1)for C-O.SEM micrographs of the synthesized TiO_2 NPs showed the aggregated and spherical in shape.The maximum efficacy was observed in the aqueous flower extract of C.gigantea and synthesized TiO_2 NPs against R.(B.)microplus(LC_(50)=24.63 and 5.43 mg/L and r^2=0.960 and 0.988)and against H.bispinosa(LC_(50)=35.22 and 9.15 mg/L and r^2=0.969 and 0.969).respectively.Conclusions:The synthesized TiO_2 NPs were highly stable and had significant acaricidal activity against the larvae of R.(B.)microplus and adult of H.bispinosa.This study provides the first report of synthesized TiO_2 NPs and possessed excellent anti-parasitic activity.展开更多
Objective:To analyze the phytochemical composition and in vitro antioxidant properties of aqueous extract of Aerva Lanata（A.lanata） stem.Methods:During the preliminary phytochemical analysis,the aqueous extract of A...Objective:To analyze the phytochemical composition and in vitro antioxidant properties of aqueous extract of Aerva Lanata（A.lanata） stem.Methods:During the preliminary phytochemical analysis,the aqueous extract of A.Ianata was screened for the presence of carbohydrates,proteins,phenolic compounds,oil and fats,saponins,flavonoids,alkaloids. tannins and phytosterols.Antioxidant activity of the extract was determined by 2.2-dipbenyl- 1-picrylhydrazyl radical scavenging activity,metal chelating activity,reducing power activity and DNA damage inhibition activity.Analysis of phenolic compounds was performed by FolinCiocaiteau reagent method and gradient high performance liquid chromatography technique. Results:Preliminary phytochemical analysis exhibited the presence of phenolic compounds, saponins.flavonoids.tannins and phytosterols as major phytochemical groups.The extract exhibited high 2.2—diphenyl-1-picrylhydrazyl radical scavenging activity(IC<sub>50</sub>= 110.74μg/ mL).metal chelating activity(IC<sub>50</sub>= 758.17μg/mL).reducing power activity and DIA damage inhibition efficiency.The extract was reported to possess a high amount of total phenolic content and some of them were identified as gallic acid（3,4,3-OH）,apigenin-7—O-glucoside tapigetrin), quercetin-3—O-rutinoside（rutin） and myricetin（3,5,7,3,4,5-OH）by high performance liquid chromatography analysis.The extract was found non toxic towards human erythrocytes in the hemolytic assay(IC<sub>50</sub>= 24.89 mg/mL).Conclusions:These results conclud that A.lanata stem possesses high antioxidant activity and can he used for the development of natural and sale antioxidant compounds.展开更多
The present study was focused on screening and characterization of tyrosinase enzyme produced by marine actinobacteria and its application in phenolic compounds removal from aqueous solution. A total of 20 strains wer...The present study was focused on screening and characterization of tyrosinase enzyme produced by marine actinobacteria and its application in phenolic compounds removal from aqueous solution. A total of 20 strains were isolated from marine sediment sample and screened for tyrosinase production by using skimmed milk agar medium. Among 20 isolates, two isolates LK-4 and LK-20 showed zone of hydrolysis and these were taken for secondary screening by using tyrosiue agar medium. Based on the result of secondary screening LK-4 was selected for further analysis, such as tyrosinase assay, protein content and specific activity of the enzyme. The tyrosinase enzyme was produced in a SS medium and was partially purified by ammonium sulfate precipitation, dialysis and SDS PAGE. The isolate （LK-4） was identified as Streptomyces espinosus using 16S rRNA gene sequencing and named as ＂Streptomyces espinosus strain LK4 （KF806735）＂. The tyrosinase enzyme was immobilized in sodium alginate which was applied to remove phenolic compounds from water. The enzyme efficiently removed the phenolic compounds from aqueous solution within few hours which indicated that tyrosinasc enzyme produced by Streptomyces espinosus strain LK-4 can be potently used for the removal of phenol and phenolic compounds from wastewater in industries.展开更多
Microbes serve as the most important resource for drug discovery.During our screening for bioactive compounds from our natural products library,a pathogenic fungus,Microdochium majus strain 99049,from wheat was select...Microbes serve as the most important resource for drug discovery.During our screening for bioactive compounds from our natural products library,a pathogenic fungus,Microdochium majus strain 99049,from wheat was selected for further investigation.A new alkaloid named brocaeloid D(1),together with six previously characterized compounds(2–7)were identified.Compound 1 belongs to 4-oxoquinoline with C-2 reversed prenylation and a succinimide substructure.All the structures of these newly isolated compounds were determined by different means in spectroscopic experiments.The absolute configurations of 1 was further deduced from comparison of its CD spectrum with that of known compound 2.The bioactivities of these identified compounds were evaluated against several pathogenic microorganisms and cancer cell lines.Compounds 1–5 showed activity against HUH-7 human hepatoma cells with IC50 values of 80μg/mL.Compound 6 showed mild activity against HeLa cells(IC50=51.9μg/mL),weak anti-MTB activity(MIC=80μg/mL),and moderate anti-MRSA activity(MIC=25μg/mL),and compound 7 showed weak anti-MRSA activity(MIC=100μg/mL).展开更多
Staphyloccus aureus （S. aureus） is a well known human pathogen known to causes a verity of infections in humans. In recent years S. aureus is reported to show drug resistant toward commonly known drugs. Therefore, t...Staphyloccus aureus （S. aureus） is a well known human pathogen known to causes a verity of infections in humans. In recent years S. aureus is reported to show drug resistant toward commonly known drugs. Therefore, this study was designed to study the pattern of antibiotic resistance in 50 clinical isolates ofS. aureus isolated at Dhanwantri Hospital and Research Centre, Jaipur, Rajasthan, India. S. aureus cultures were isolated from different clinical samples, pus, throat swabs and urine on Blood agar and MacConkey agar and Chrom agar plats and characterized by an array of microscopic and biochemical tests. Antibiotic sensitivity test was performed by standard disc diffusion method （Kirby bayer＇s method） on Muller Hinton agar plates. During this study, among 50 S. aureus isolates 48 （96%） were found to be resistance toward Aztreonam and Doxicycline followed by Ciprofloxacin （n = 45, 90%）, Cefpodoxime and Ceftazidime （n = 44, 88%）, Cefuroxime （n = 40, 80%）, Pipracillin ＋ Tazobactum （n = 38, 76%）, Cefoparazone （n = 36, 72%）, Amoxicillin ＋ Clavulanic acid and Ceftriaxone （n = 33, 66%）, Levofloxacin （n = 32, 64%）, Moxifloxacin （n = 31, 62%）, Ofloaxacin （n = 25, 50%）, Cloxacillin （n = 22, 44%）, Azithromycin （n = 21, 42%）, Clindamycin （n = 19, 38%）, Meropenem （n = 18, 36%）, Clarithromycin （n = 16, 32%）, Ampicillin ＋ sulbactam （n = 13, 26%）, Amikacin （n = 12, 24%）, Impipenem （n = 8, 16%）, Linezolid and Methicillin （n = 7, 14%） and Teicoplanin （n = 3, 6%）. In conclusion, the isolated S. aureus found to be resistant toward common antibiotics, however all isolates were found to be susceptible to Vancomycin.展开更多
文摘Objective:To investigate the antioxidant activity of marine actinobacteria.Methods:The content of total phenolics,the level of antioxidant potential by DPPH radical scavenging activity,metal chelating activity,FRAP method,βcarotene assay and NO scavenging activity in extract were determined.Results:In all the methods the extract exhibited good scavenging activity except NO scavenging activity.The IC<sub>50</sub> values of marine actinobacteria extract on DPPH radical were found to be 41.09μg/mL.The zone of color retention was 12 mm inβ-carotene bleaching assay. DNA protective efficiency of the extracts was also studied using UV- photolysed H<sub>2</sub>O<sub>2</sub>-driven oxidative damage to pBR322.HPLC analysis identified some of the major phenolic compounds in extracts,which might he responsible for the antioxidant potential and cyto-protection.It showed a 100%cytotoxic effect in brine shrimp lethality assay within 10 mins.The novel actinobacteria was identified as Streptomyces LK-3（JF710608） through I6S rDNA Sequencing.Conclusions:The results obtained suggest that the extracts bear anti-cancer metabolites and could be considered as a potential source for anti-cancer drug development.
文摘Objective:To assess the acaricidal activity of titanium dioxide nanoparticles(TiO_2 NPs)synthesized from flower aqueous extract of Calotropis gigantea(C.gigantea)against the larvae of Rhipicephalus(Boophilus)microplus[R.(B.)microplus]and the adult of Haemaphrysalis bispinosa(H.bispinosa).Methods:The lyophilized C.gigantea flower aqueous extract of 50 mg was added with 100 mL of TiO(OH_2)(10 mM)and magnetically stirred for 6 h.Synthesized TiO_2 NPs were characterized by X-ray diffraction(XRD).Fourier transform infrared spectroscopy(FTIR),Scanning electron microscopy(SEM),and Energy dispersive X-ray spectroscopy(EDX).The synthesised TiO_2 NPs were tested against the larvae of R(B.)microplus and adult of H.bispinosa were exposed to filter paper impregnated method.Results:XRD confirmed the crystalline nature of the nanoparticles with the mean size of 10.52 nm.The functional groups for synthesized TiO_2NPs were 1405.19,and 1053.45 cm^(-1)for-NH_2 bending,primary amines and amides and 1053.84and 1078.45 cm^(-1)for C-O.SEM micrographs of the synthesized TiO_2 NPs showed the aggregated and spherical in shape.The maximum efficacy was observed in the aqueous flower extract of C.gigantea and synthesized TiO_2 NPs against R.(B.)microplus(LC_(50)=24.63 and 5.43 mg/L and r^2=0.960 and 0.988)and against H.bispinosa(LC_(50)=35.22 and 9.15 mg/L and r^2=0.969 and 0.969).respectively.Conclusions:The synthesized TiO_2 NPs were highly stable and had significant acaricidal activity against the larvae of R.(B.)microplus and adult of H.bispinosa.This study provides the first report of synthesized TiO_2 NPs and possessed excellent anti-parasitic activity.
文摘Objective:To analyze the phytochemical composition and in vitro antioxidant properties of aqueous extract of Aerva Lanata（A.lanata） stem.Methods:During the preliminary phytochemical analysis,the aqueous extract of A.Ianata was screened for the presence of carbohydrates,proteins,phenolic compounds,oil and fats,saponins,flavonoids,alkaloids. tannins and phytosterols.Antioxidant activity of the extract was determined by 2.2-dipbenyl- 1-picrylhydrazyl radical scavenging activity,metal chelating activity,reducing power activity and DNA damage inhibition activity.Analysis of phenolic compounds was performed by FolinCiocaiteau reagent method and gradient high performance liquid chromatography technique. Results:Preliminary phytochemical analysis exhibited the presence of phenolic compounds, saponins.flavonoids.tannins and phytosterols as major phytochemical groups.The extract exhibited high 2.2—diphenyl-1-picrylhydrazyl radical scavenging activity(IC<sub>50</sub>= 110.74μg/ mL).metal chelating activity(IC<sub>50</sub>= 758.17μg/mL).reducing power activity and DIA damage inhibition efficiency.The extract was reported to possess a high amount of total phenolic content and some of them were identified as gallic acid（3,4,3-OH）,apigenin-7—O-glucoside tapigetrin), quercetin-3—O-rutinoside（rutin） and myricetin（3,5,7,3,4,5-OH）by high performance liquid chromatography analysis.The extract was found non toxic towards human erythrocytes in the hemolytic assay(IC<sub>50</sub>= 24.89 mg/mL).Conclusions:These results conclud that A.lanata stem possesses high antioxidant activity and can he used for the development of natural and sale antioxidant compounds.
文摘The present study was focused on screening and characterization of tyrosinase enzyme produced by marine actinobacteria and its application in phenolic compounds removal from aqueous solution. A total of 20 strains were isolated from marine sediment sample and screened for tyrosinase production by using skimmed milk agar medium. Among 20 isolates, two isolates LK-4 and LK-20 showed zone of hydrolysis and these were taken for secondary screening by using tyrosiue agar medium. Based on the result of secondary screening LK-4 was selected for further analysis, such as tyrosinase assay, protein content and specific activity of the enzyme. The tyrosinase enzyme was produced in a SS medium and was partially purified by ammonium sulfate precipitation, dialysis and SDS PAGE. The isolate （LK-4） was identified as Streptomyces espinosus using 16S rRNA gene sequencing and named as ＂Streptomyces espinosus strain LK4 （KF806735）＂. The tyrosinase enzyme was immobilized in sodium alginate which was applied to remove phenolic compounds from water. The enzyme efficiently removed the phenolic compounds from aqueous solution within few hours which indicated that tyrosinasc enzyme produced by Streptomyces espinosus strain LK-4 can be potently used for the removal of phenol and phenolic compounds from wastewater in industries.
基金This work was partially supported by the grants from the National Natural Science Foundation of China(31430002,81573341,21877038,31720103901,31320103911)Taishan Scholarship,Open Project Funding of the State Key Laboratory of Bioreactor Engineering,the 111 Project(B18022)+1 种基金National Key R&D Program of China 2017YFE0108200the Fundamental Research Funds for the Central Universities(22221818014).
文摘Microbes serve as the most important resource for drug discovery.During our screening for bioactive compounds from our natural products library,a pathogenic fungus,Microdochium majus strain 99049,from wheat was selected for further investigation.A new alkaloid named brocaeloid D(1),together with six previously characterized compounds(2–7)were identified.Compound 1 belongs to 4-oxoquinoline with C-2 reversed prenylation and a succinimide substructure.All the structures of these newly isolated compounds were determined by different means in spectroscopic experiments.The absolute configurations of 1 was further deduced from comparison of its CD spectrum with that of known compound 2.The bioactivities of these identified compounds were evaluated against several pathogenic microorganisms and cancer cell lines.Compounds 1–5 showed activity against HUH-7 human hepatoma cells with IC50 values of 80μg/mL.Compound 6 showed mild activity against HeLa cells(IC50=51.9μg/mL),weak anti-MTB activity(MIC=80μg/mL),and moderate anti-MRSA activity(MIC=25μg/mL),and compound 7 showed weak anti-MRSA activity(MIC=100μg/mL).
文摘Staphyloccus aureus （S. aureus） is a well known human pathogen known to causes a verity of infections in humans. In recent years S. aureus is reported to show drug resistant toward commonly known drugs. Therefore, this study was designed to study the pattern of antibiotic resistance in 50 clinical isolates ofS. aureus isolated at Dhanwantri Hospital and Research Centre, Jaipur, Rajasthan, India. S. aureus cultures were isolated from different clinical samples, pus, throat swabs and urine on Blood agar and MacConkey agar and Chrom agar plats and characterized by an array of microscopic and biochemical tests. Antibiotic sensitivity test was performed by standard disc diffusion method （Kirby bayer＇s method） on Muller Hinton agar plates. During this study, among 50 S. aureus isolates 48 （96%） were found to be resistance toward Aztreonam and Doxicycline followed by Ciprofloxacin （n = 45, 90%）, Cefpodoxime and Ceftazidime （n = 44, 88%）, Cefuroxime （n = 40, 80%）, Pipracillin ＋ Tazobactum （n = 38, 76%）, Cefoparazone （n = 36, 72%）, Amoxicillin ＋ Clavulanic acid and Ceftriaxone （n = 33, 66%）, Levofloxacin （n = 32, 64%）, Moxifloxacin （n = 31, 62%）, Ofloaxacin （n = 25, 50%）, Cloxacillin （n = 22, 44%）, Azithromycin （n = 21, 42%）, Clindamycin （n = 19, 38%）, Meropenem （n = 18, 36%）, Clarithromycin （n = 16, 32%）, Ampicillin ＋ sulbactam （n = 13, 26%）, Amikacin （n = 12, 24%）, Impipenem （n = 8, 16%）, Linezolid and Methicillin （n = 7, 14%） and Teicoplanin （n = 3, 6%）. In conclusion, the isolated S. aureus found to be resistant toward common antibiotics, however all isolates were found to be susceptible to Vancomycin.
