Objective:To evaluate the anti-bacterial and anti-oxidant activity of and rographolide(AND)and echiodinin(ECH)of Andrographis paniculata.Methods:In this study,an attempt has been made to demonstrate the anti-microbial...Objective:To evaluate the anti-bacterial and anti-oxidant activity of and rographolide(AND)and echiodinin(ECH)of Andrographis paniculata.Methods:In this study,an attempt has been made to demonstrate the anti-microbial and anti-oxidant activity of isolated AND and ECH by broth micro-dilution method and 2,2-dipheny l-2-picryl-hydrazyl(DPPH)assay,respectively.Structure elucidation was determined by electro-spray ionization-MSD,NMR(1H and13C)and IR spectra.Results:AND was effective against most of the strains tested including Mycobacterium smegmatis,showing broad spectrum of growth inhibition activity with Minimum inhibitory concentration values againstStaphylococcus aureus(100μg/mL),Streptococcus thermophilus(350μg/mL)Bacillus subtilis(100μg/mL),Escherichia coli(50μg/mL),Mycobacterium smegmatis(200μg/mL),Klebsiella pneumonia(100μg/mL),andPseudomonas aeruginosa(200μg/mL).ECH showed specific anti-bacterial activity against Staphylococcus aureus,Escherichia coli,Bacillus subtilis and Pseudomonas aeruginosaat a concentration higher than 225μg/mL.Both AND and ECH were not effective against the two yeast strains,Candida albicansand Saccharomyces cerevisiae tested in this study.Conclusion:This preliminary study showed promising anti-bacterial activity and moderate free radical scavenging activity of AND and ECH,and it may provide the scientific rationale for its popular folklore medicines.展开更多
We present a statistical method to derive the stellar density profiles of the Milky Way from spectroscopic survey data, taking into account selection effects. We assume the selection function, which can be altered dur...We present a statistical method to derive the stellar density profiles of the Milky Way from spectroscopic survey data, taking into account selection effects. We assume the selection function, which can be altered during observations and data reductions, of the spectroscopic survey is based on photometric colors and magnitude. Then the underlying selection function for a line-of-sight can be recovered well by comparing the distribution of the spectroscopic stars in a color-magnitude plane with that of the photometric dataset. Subsequently, the stellar density profile along a line-of-sight can be derived from the spectroscopically measured stellar density profile multiplied by the selection function. The method is validated using Galaxia mock data with two different selection functions. We demonstrate that the derived stellar density profiles reconstruct the true ones well not only for the full set of targets, but also for sub-populations selected from the full dataset. Finally, the method is applied to map the density pro- files for the Galactic disk and halo, using the LAMOST RGB stars. The Galactic disk extends to about R = 19 kpc, where the disk still contributes about 10% to the total stellar surface density. Beyond this radius, the disk smoothly transitions to the halo without any truncation, bending or breaking. Moreover, no over-density corresponding to the Monoceros ring is found in the Galactic anti-center direction. The disk shows moderate north-south asymmetry at radii larger than 12 kpc. On the other hand, the R-Z tomographic map directly shows that the stellar halo is substantially oblate within a Galactocentric radius of 20 kpc and gradually becomes nearly spherical beyond 30 kpc.展开更多
Introduction: The rise in antibiotic resistant cases has caused a global concern. Researchers around the world are trying to find a novel alternative to combat this issue. Green tea with its many health benefits, incl...Introduction: The rise in antibiotic resistant cases has caused a global concern. Researchers around the world are trying to find a novel alternative to combat this issue. Green tea with its many health benefits, including antibacterial and antiviral activity, has shown to be one of the most promising candidates to be used as an agent to solve this problem. Objective: This study focuses on evaluating the synergistic effects of antibiotics and two green tea polyphenols: epigallocatechin gallate (EGCG), and its modified lipophilic form epigallocatechin gallate stearate (EGCG-S). Methods: In this study, twelve antibiotics and eight bacteria: Gram-positive Staphylococcus aureus (S. aureus), Staphylococcus epidermidis (S. epidermidis) and Bacillus megaterium (B. megaterium);Gram-negative Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Serratia marcescens (S. marcescens), and Enterobacter aerogenes (E. aerogenes);and acid-fast Mycobacterium smegmatis (M. smegmatis) were used. Antibacterial synergism profiling of EGCG, EGCG-S and antibiotics has been established using a disk diffusion assay. Results: The results revealed that both 1% of EGCG and 1% EGCG-S enhanced the antimicrobial activities on antibiotics in various bacteria. Antimicrobial susceptibility study indicated that EGCG-S was able to enhance some antibiotics from the resistant category to intermediate or susceptible and/or from intermediate category to susceptible. Both EGCG and EGCG-S worked comparably on Gram-positive bacteria;in S. aureus, both compounds enhanced 5 antibiotics (AM10, CF30, C30, S10 and TE30) activities while EGCG-S had higher efficiency. B. megaterium were susceptible to most of the antibiotic treatment, thus the impact of EGCG and EGCG-S was insignificant. EGCG-S worked better than EGCG on Gram-negative bacteria;converted 9 antibiotics susceptibility in E. coli and P. aeruginosa, and 8 antibiotics in E. aerogenes. EGCG and EGCG-S also showed synergism on acid-fast bacteria M. smegmatis with EGCG-S has much higher efficiency than EGCG. Conclusion: The results suggested that EGCG-S might be a promising antibacterial synergistic agent with antibiotics to combat antibiotic-resistant bacteria.展开更多
基金Financially supported by Universiti Malaysia Kelantan(Grant No.R/SGJP/A07.00/00710A/001/2012/000081)
文摘Objective:To evaluate the anti-bacterial and anti-oxidant activity of and rographolide(AND)and echiodinin(ECH)of Andrographis paniculata.Methods:In this study,an attempt has been made to demonstrate the anti-microbial and anti-oxidant activity of isolated AND and ECH by broth micro-dilution method and 2,2-dipheny l-2-picryl-hydrazyl(DPPH)assay,respectively.Structure elucidation was determined by electro-spray ionization-MSD,NMR(1H and13C)and IR spectra.Results:AND was effective against most of the strains tested including Mycobacterium smegmatis,showing broad spectrum of growth inhibition activity with Minimum inhibitory concentration values againstStaphylococcus aureus(100μg/mL),Streptococcus thermophilus(350μg/mL)Bacillus subtilis(100μg/mL),Escherichia coli(50μg/mL),Mycobacterium smegmatis(200μg/mL),Klebsiella pneumonia(100μg/mL),andPseudomonas aeruginosa(200μg/mL).ECH showed specific anti-bacterial activity against Staphylococcus aureus,Escherichia coli,Bacillus subtilis and Pseudomonas aeruginosaat a concentration higher than 225μg/mL.Both AND and ECH were not effective against the two yeast strains,Candida albicansand Saccharomyces cerevisiae tested in this study.Conclusion:This preliminary study showed promising anti-bacterial activity and moderate free radical scavenging activity of AND and ECH,and it may provide the scientific rationale for its popular folklore medicines.
基金supported by the Strategic Priority Research Program“The Emergence of Cosmological Structures”of the Chinese Academy of Sciences(Grant No.XDB09000000)the National Key Basic Research Program of China(2014CB845700)+1 种基金the National Natural Science Foundation of China(Grant Nos.11373032 and 11333003)a National Major Scientific Project built by the Chinese Academy of Sciences.Funding for the project has been provided by the project has been provided by the National Development and Reform Commission
文摘We present a statistical method to derive the stellar density profiles of the Milky Way from spectroscopic survey data, taking into account selection effects. We assume the selection function, which can be altered during observations and data reductions, of the spectroscopic survey is based on photometric colors and magnitude. Then the underlying selection function for a line-of-sight can be recovered well by comparing the distribution of the spectroscopic stars in a color-magnitude plane with that of the photometric dataset. Subsequently, the stellar density profile along a line-of-sight can be derived from the spectroscopically measured stellar density profile multiplied by the selection function. The method is validated using Galaxia mock data with two different selection functions. We demonstrate that the derived stellar density profiles reconstruct the true ones well not only for the full set of targets, but also for sub-populations selected from the full dataset. Finally, the method is applied to map the density pro- files for the Galactic disk and halo, using the LAMOST RGB stars. The Galactic disk extends to about R = 19 kpc, where the disk still contributes about 10% to the total stellar surface density. Beyond this radius, the disk smoothly transitions to the halo without any truncation, bending or breaking. Moreover, no over-density corresponding to the Monoceros ring is found in the Galactic anti-center direction. The disk shows moderate north-south asymmetry at radii larger than 12 kpc. On the other hand, the R-Z tomographic map directly shows that the stellar halo is substantially oblate within a Galactocentric radius of 20 kpc and gradually becomes nearly spherical beyond 30 kpc.
文摘Introduction: The rise in antibiotic resistant cases has caused a global concern. Researchers around the world are trying to find a novel alternative to combat this issue. Green tea with its many health benefits, including antibacterial and antiviral activity, has shown to be one of the most promising candidates to be used as an agent to solve this problem. Objective: This study focuses on evaluating the synergistic effects of antibiotics and two green tea polyphenols: epigallocatechin gallate (EGCG), and its modified lipophilic form epigallocatechin gallate stearate (EGCG-S). Methods: In this study, twelve antibiotics and eight bacteria: Gram-positive Staphylococcus aureus (S. aureus), Staphylococcus epidermidis (S. epidermidis) and Bacillus megaterium (B. megaterium);Gram-negative Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Serratia marcescens (S. marcescens), and Enterobacter aerogenes (E. aerogenes);and acid-fast Mycobacterium smegmatis (M. smegmatis) were used. Antibacterial synergism profiling of EGCG, EGCG-S and antibiotics has been established using a disk diffusion assay. Results: The results revealed that both 1% of EGCG and 1% EGCG-S enhanced the antimicrobial activities on antibiotics in various bacteria. Antimicrobial susceptibility study indicated that EGCG-S was able to enhance some antibiotics from the resistant category to intermediate or susceptible and/or from intermediate category to susceptible. Both EGCG and EGCG-S worked comparably on Gram-positive bacteria;in S. aureus, both compounds enhanced 5 antibiotics (AM10, CF30, C30, S10 and TE30) activities while EGCG-S had higher efficiency. B. megaterium were susceptible to most of the antibiotic treatment, thus the impact of EGCG and EGCG-S was insignificant. EGCG-S worked better than EGCG on Gram-negative bacteria;converted 9 antibiotics susceptibility in E. coli and P. aeruginosa, and 8 antibiotics in E. aerogenes. EGCG and EGCG-S also showed synergism on acid-fast bacteria M. smegmatis with EGCG-S has much higher efficiency than EGCG. Conclusion: The results suggested that EGCG-S might be a promising antibacterial synergistic agent with antibiotics to combat antibiotic-resistant bacteria.
