Objective:This study has been done to evaluate the interaction between water extracts of Psidium guajava, Rosmarinus officinalis,Salvia fruticosa,Majorana syriaca,Ocimum basilucum,Syzygium aromaticum,Laurus nobilis,an...Objective:This study has been done to evaluate the interaction between water extracts of Psidium guajava, Rosmarinus officinalis,Salvia fruticosa,Majorana syriaca,Ocimum basilucum,Syzygium aromaticum,Laurus nobilis,and Rosa damascena alone and then synergy testing of these extracts with known antimicrobial agents including oxytetracycline HCl,gentamicin sulfate,penicillin G,cephalexin and enrofloxacin.This study was conducted against five S.aureus isolates;one is Methicillin -resistant Staphylococcus aureus(MRSA) and 4 Methicillin - sensitive Staphylococcus aureus(MSSA).Methods:Evaluation of the interaction between plant extracts and different antimicrobial agents has been done using well - diffusion and microdilution methods. Results:The results of the conducted experiments using well - diffusion method demonstrate that these plants showed in vitro interactions between antimicrobial agents and plant extracts were additive,while using microdilution method showed synergistic effects with significant reduction in the MICs of the test antibiotics against these strains of S.aureus.This change in MIC was noticed in all plant extracts against test antibiotics including these plants showed weak antibacterial activity by well diffusion method.Synergism effect was occurred in both sensitive and resistant strains but the magnitude of minimum fold reduction of inhibitory concentration in resistant strains especially MRSA strain was higher than the sensitive strains.Coclusion:This study probably suggests the possibility of concurrent use of these antimicrobial drugs and plant extracts in combination in treating infections caused by S.aureus strains or at least the concomitant administration may not impair the antimicrobial activity of these antibiotics.展开更多
Cryptotanshinone (CT), a major tanshinone of medicinal plant Salvia miltiorrhiza Bunge, demonstrated effective in vitro antibacterial activity against all oral bacteria tested in this experiment. The antibacterial act...Cryptotanshinone (CT), a major tanshinone of medicinal plant Salvia miltiorrhiza Bunge, demonstrated effective in vitro antibacterial activity against all oral bacteria tested in this experiment. The antibacterial activities of CT against oral bacteria were assessed using the checkerboard and time-kill methods to evaluate the synergistic effects of treatment with ampicillin or gentamicin. The CT was determined against oral pathogenic bacteria with MIC and MBC values ranging from 0.5 to 16 and 1 to 64 μg/mL;for am- picillin from 0.0313 to 16 and 0.125 to 32 μg/mL;for gentamicin from 2 to 256 and 4 to 512 μg/mL respectively. The range of MIC50 and MIC90 were 0.0625 - 8 μg/mL and 1 - 64 μg/mL, respectively. The combination effects of CT with antibiotics were synergistic (FIC index < 0.5) against tested oral bacteria except additive, Streptococcus sobrinus, S. criceti, and Actinobacillus actinomycetemcomitans (FIC index < 0.75 - 1.0). The MBCs were shown reducing ≥4 - 8-fold, indicating a synergistic effect as defined by a FBCI of ≤0.5. Furthermore, a time-kill study showed that the growth of the tested bacteria was completely attenuated after 3 - 6 h of treatment with the 1/2 MIC of CT, regardless of whether it was administered alone or with ampicillin or gentamicin. The results suggest that CT could be employed as a natural antibacterial agent against cariogenic and periodontopathogenic bac- teria.展开更多
The commercial development of lithium-sulfur batteries(Li-S)is severely limited by the shuttle effect of lithium polysulfides(LPSs)and the non-conductivity of sulfur.Herein,porous g-C_(3)N_(4) nanotubes(PCNNTs)are syn...The commercial development of lithium-sulfur batteries(Li-S)is severely limited by the shuttle effect of lithium polysulfides(LPSs)and the non-conductivity of sulfur.Herein,porous g-C_(3)N_(4) nanotubes(PCNNTs)are synthesized via a self-template method and utilized as an efficient sulfur host material.The one-dimensional PCNNTs have a high specific surface area(143.47 m^(2)·g^(-1))and an abundance of macro-/mesopores,which could achieve a high sulfur loading rate of 74.7wt%.A Li-S battery bearing the PCNNTs/S composite as a cathode displays a low capacity decay of 0.021% per cycle over 800 cycles at 0.5 C with an initial capacity of 704.8 mAh·g^(-1).PCNNTs with a tubular structure could alleviate the volume expansion caused by sulfur and lithium sulfide during charge/discharge cycling.High N contents could greatly enhance the adsorption capacity of the carbon nitride for LPSs.These synergistic effects contribute to the excellent cycling stability and rate performance of the PCNNTs/S composite electrode.展开更多
文摘Objective:This study has been done to evaluate the interaction between water extracts of Psidium guajava, Rosmarinus officinalis,Salvia fruticosa,Majorana syriaca,Ocimum basilucum,Syzygium aromaticum,Laurus nobilis,and Rosa damascena alone and then synergy testing of these extracts with known antimicrobial agents including oxytetracycline HCl,gentamicin sulfate,penicillin G,cephalexin and enrofloxacin.This study was conducted against five S.aureus isolates;one is Methicillin -resistant Staphylococcus aureus(MRSA) and 4 Methicillin - sensitive Staphylococcus aureus(MSSA).Methods:Evaluation of the interaction between plant extracts and different antimicrobial agents has been done using well - diffusion and microdilution methods. Results:The results of the conducted experiments using well - diffusion method demonstrate that these plants showed in vitro interactions between antimicrobial agents and plant extracts were additive,while using microdilution method showed synergistic effects with significant reduction in the MICs of the test antibiotics against these strains of S.aureus.This change in MIC was noticed in all plant extracts against test antibiotics including these plants showed weak antibacterial activity by well diffusion method.Synergism effect was occurred in both sensitive and resistant strains but the magnitude of minimum fold reduction of inhibitory concentration in resistant strains especially MRSA strain was higher than the sensitive strains.Coclusion:This study probably suggests the possibility of concurrent use of these antimicrobial drugs and plant extracts in combination in treating infections caused by S.aureus strains or at least the concomitant administration may not impair the antimicrobial activity of these antibiotics.
文摘Cryptotanshinone (CT), a major tanshinone of medicinal plant Salvia miltiorrhiza Bunge, demonstrated effective in vitro antibacterial activity against all oral bacteria tested in this experiment. The antibacterial activities of CT against oral bacteria were assessed using the checkerboard and time-kill methods to evaluate the synergistic effects of treatment with ampicillin or gentamicin. The CT was determined against oral pathogenic bacteria with MIC and MBC values ranging from 0.5 to 16 and 1 to 64 μg/mL;for am- picillin from 0.0313 to 16 and 0.125 to 32 μg/mL;for gentamicin from 2 to 256 and 4 to 512 μg/mL respectively. The range of MIC50 and MIC90 were 0.0625 - 8 μg/mL and 1 - 64 μg/mL, respectively. The combination effects of CT with antibiotics were synergistic (FIC index < 0.5) against tested oral bacteria except additive, Streptococcus sobrinus, S. criceti, and Actinobacillus actinomycetemcomitans (FIC index < 0.75 - 1.0). The MBCs were shown reducing ≥4 - 8-fold, indicating a synergistic effect as defined by a FBCI of ≤0.5. Furthermore, a time-kill study showed that the growth of the tested bacteria was completely attenuated after 3 - 6 h of treatment with the 1/2 MIC of CT, regardless of whether it was administered alone or with ampicillin or gentamicin. The results suggest that CT could be employed as a natural antibacterial agent against cariogenic and periodontopathogenic bac- teria.
基金financially supported by the Natural Science Sci-ence Foundation of Jiangsu Province,China(No.BK20181469)the Guangdong Basic and Applied Basic Research Foundation(No.2020A1515110035)the Science and Technology Planning Social Development Project of Zhenji-ang City,China(No.SSH20190140049).
文摘The commercial development of lithium-sulfur batteries(Li-S)is severely limited by the shuttle effect of lithium polysulfides(LPSs)and the non-conductivity of sulfur.Herein,porous g-C_(3)N_(4) nanotubes(PCNNTs)are synthesized via a self-template method and utilized as an efficient sulfur host material.The one-dimensional PCNNTs have a high specific surface area(143.47 m^(2)·g^(-1))and an abundance of macro-/mesopores,which could achieve a high sulfur loading rate of 74.7wt%.A Li-S battery bearing the PCNNTs/S composite as a cathode displays a low capacity decay of 0.021% per cycle over 800 cycles at 0.5 C with an initial capacity of 704.8 mAh·g^(-1).PCNNTs with a tubular structure could alleviate the volume expansion caused by sulfur and lithium sulfide during charge/discharge cycling.High N contents could greatly enhance the adsorption capacity of the carbon nitride for LPSs.These synergistic effects contribute to the excellent cycling stability and rate performance of the PCNNTs/S composite electrode.
