Objective: To identify the main chemical classes of compounds from aqueous extract of Enterolobium contortisiliquum(E. contortisiliquum) seed bark and to evaluate its antibacterial activity, as well as its potential t...Objective: To identify the main chemical classes of compounds from aqueous extract of Enterolobium contortisiliquum(E. contortisiliquum) seed bark and to evaluate its antibacterial activity, as well as its potential to increase the activity of antibiotics against strains of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli.Methods: Different classes of compounds in the aqueous extract of E. contortisiliquum were evaluated based on the visual changes in the coloration and the formation of precipitate after the addition of specific reagents. The antibacterial activity of the extract and its potential to increase of antibiotic activity of antibiotics drugs, gentamicin and norfloxacin was determined by using the microdilution method.Results: Our results demonstrated that the following secondary metabolites were presented in E. contortisiliquum seed bark: flavones, flavonols, xanthones, flavononols,chalcones, aurones, flavones and catechins. The extract itself had very low antibacterial activity against all bacterial strains tested(MIC ≥ 1024 μg/m L), but there was an increase in the antibiotic activity of gentamicin and norfloxacin when combined in the subinhibitory concentration(i.e., MIC/8).Conclusions: Our data suggests that E. contortisiliquum seed bark may be an alternative source for new drugs with the potential to increase antibiotic activity against different strains of bacteria.展开更多
Biorecycling microbes, which have critical functionalities in natural cycles, are essential to sustain eco-system of the earth. Any alterations in these cycles caused by the mutations of microbes could be a potential ...Biorecycling microbes, which have critical functionalities in natural cycles, are essential to sustain eco-system of the earth. Any alterations in these cycles caused by the mutations of microbes could be a potential threat to life on earth. Antibiotics leached from pharmaceutical waste, animal food and agribusiness prod- ucts are accumulating in the environment. Metal nanoparticles are also accumulating in environment because of their extensive use as biocidal agent in domestic products. Interaction of antibiotics and metal nanoparticles with eco-ffiendly microorganisms has a potential to alter the ecosystem of the earth. In this article, we have studied the antibacterial activities of silver and copper nanoparticles and their for- mulations with antibiotics, tetracycline, and kanamycin against biorecycling microbes, Bacillus subtilis and Pseudomonas fluorescens. Strong synergistic effect of metal nanoparticles on the antimicrobial ac- tivities of commercial antibiotics has been observed. Antimicrobial activity of tetracycline improves by 286%-346% and 0%-28% when being tested in the presence of 250 ppm of silver and copper nanoparticles, respectively. For kanamycin, the improvement is 154%-289% for silver and 3%-20% for copper nanoparticles. Irrespective of the antibiotics and tested organisms, synergy is more prominent for silver nanoparticles even at their minimum active concentration (100 ppm). This study demonstrates that the combination of metal nanoparticles with antibiotics could be more fatal to ecosystem than either the metal nanoparticles or the antibiotics alone.展开更多
It is known that many kinds of fermentative antibiotics can be removed by temperatureenhanced hydrolysis from production wastewater based on their easy-to-hydrolyze characteristics.However,a few aminoglycosides are ha...It is known that many kinds of fermentative antibiotics can be removed by temperatureenhanced hydrolysis from production wastewater based on their easy-to-hydrolyze characteristics.However,a few aminoglycosides are hard to hydrolyze below 100℃ because of their stability expressed by high molecular energy gap(E).Herein,removal of hard-to-hydrolyze kanamycin residue from production wastewater by hydrothermal treatment at subcritical temperatures was investigated.The results showed the reaction temperature had a significant impact on kanamycin degradation.The degradation half-life(t1/2)was shortened by 87.17-fold when the hydrothermal treatment temperature was increased from 100℃ to 180℃.The t1/2 of kanamycin in the N2 process was extended by 1.08-1.34-fold compared to that of the corresponding air process at reaction temperatures of 140-180℃,indicating that the reactions during hydrothermal treatment process mainly include oxidation and hydrolysis.However,the contribution of hydrolysis was calculated as 75%-98%,which showed hydrolysis played a major role during the process,providing possibilities for the removal of kanamycin from production wastewaters with high-concentration organic matrices.Five transformation products with lower antibacterial activity than kanamycin were identified using UPLC-QTOF-MS analysis.More importantly,hydrothermal treatment could remove 97.9%of antibacterial activity(kanamycin EQ,1,109 mg/L)from actual production wastewater with CODCr around 100,000 mg/L.Furthermore,the methane production yield in anaerobic inhibition tests could be increased about 2.3 times by adopting the hydrothermal pretreatment.Therefore,it is concluded that hydrothermal treatment as a pretreatment technology is an efficient method for removing high-concentration hard-to-hydrolyze antibiotic residues from wastewater with high-concentration organic matrices.展开更多
文摘Objective: To identify the main chemical classes of compounds from aqueous extract of Enterolobium contortisiliquum(E. contortisiliquum) seed bark and to evaluate its antibacterial activity, as well as its potential to increase the activity of antibiotics against strains of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli.Methods: Different classes of compounds in the aqueous extract of E. contortisiliquum were evaluated based on the visual changes in the coloration and the formation of precipitate after the addition of specific reagents. The antibacterial activity of the extract and its potential to increase of antibiotic activity of antibiotics drugs, gentamicin and norfloxacin was determined by using the microdilution method.Results: Our results demonstrated that the following secondary metabolites were presented in E. contortisiliquum seed bark: flavones, flavonols, xanthones, flavononols,chalcones, aurones, flavones and catechins. The extract itself had very low antibacterial activity against all bacterial strains tested(MIC ≥ 1024 μg/m L), but there was an increase in the antibiotic activity of gentamicin and norfloxacin when combined in the subinhibitory concentration(i.e., MIC/8).Conclusions: Our data suggests that E. contortisiliquum seed bark may be an alternative source for new drugs with the potential to increase antibiotic activity against different strains of bacteria.
基金financially supported by the University Grants Commission,New Delhi(scheme No.F.No.42-850/2013(SR))
文摘Biorecycling microbes, which have critical functionalities in natural cycles, are essential to sustain eco-system of the earth. Any alterations in these cycles caused by the mutations of microbes could be a potential threat to life on earth. Antibiotics leached from pharmaceutical waste, animal food and agribusiness prod- ucts are accumulating in the environment. Metal nanoparticles are also accumulating in environment because of their extensive use as biocidal agent in domestic products. Interaction of antibiotics and metal nanoparticles with eco-ffiendly microorganisms has a potential to alter the ecosystem of the earth. In this article, we have studied the antibacterial activities of silver and copper nanoparticles and their for- mulations with antibiotics, tetracycline, and kanamycin against biorecycling microbes, Bacillus subtilis and Pseudomonas fluorescens. Strong synergistic effect of metal nanoparticles on the antimicrobial ac- tivities of commercial antibiotics has been observed. Antimicrobial activity of tetracycline improves by 286%-346% and 0%-28% when being tested in the presence of 250 ppm of silver and copper nanoparticles, respectively. For kanamycin, the improvement is 154%-289% for silver and 3%-20% for copper nanoparticles. Irrespective of the antibiotics and tested organisms, synergy is more prominent for silver nanoparticles even at their minimum active concentration (100 ppm). This study demonstrates that the combination of metal nanoparticles with antibiotics could be more fatal to ecosystem than either the metal nanoparticles or the antibiotics alone.
基金supported by the National Natural Science Foundation of China(Nos.21590814 and 81861138051)。
文摘It is known that many kinds of fermentative antibiotics can be removed by temperatureenhanced hydrolysis from production wastewater based on their easy-to-hydrolyze characteristics.However,a few aminoglycosides are hard to hydrolyze below 100℃ because of their stability expressed by high molecular energy gap(E).Herein,removal of hard-to-hydrolyze kanamycin residue from production wastewater by hydrothermal treatment at subcritical temperatures was investigated.The results showed the reaction temperature had a significant impact on kanamycin degradation.The degradation half-life(t1/2)was shortened by 87.17-fold when the hydrothermal treatment temperature was increased from 100℃ to 180℃.The t1/2 of kanamycin in the N2 process was extended by 1.08-1.34-fold compared to that of the corresponding air process at reaction temperatures of 140-180℃,indicating that the reactions during hydrothermal treatment process mainly include oxidation and hydrolysis.However,the contribution of hydrolysis was calculated as 75%-98%,which showed hydrolysis played a major role during the process,providing possibilities for the removal of kanamycin from production wastewaters with high-concentration organic matrices.Five transformation products with lower antibacterial activity than kanamycin were identified using UPLC-QTOF-MS analysis.More importantly,hydrothermal treatment could remove 97.9%of antibacterial activity(kanamycin EQ,1,109 mg/L)from actual production wastewater with CODCr around 100,000 mg/L.Furthermore,the methane production yield in anaerobic inhibition tests could be increased about 2.3 times by adopting the hydrothermal pretreatment.Therefore,it is concluded that hydrothermal treatment as a pretreatment technology is an efficient method for removing high-concentration hard-to-hydrolyze antibiotic residues from wastewater with high-concentration organic matrices.