Displaying publications 121 - 140 of 276 in total

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  1. Molecular insights into 14-membered macrolides using the MM-PBSA method
    Yam WK, Wahab HA
    J Chem Inf Model, 2009 Jun;49(6):1558-67.
    PMID: 19469526 DOI: 10.1021/ci8003495
    Erythromycin A and roxithromycin are clinically important macrolide antibiotics that selectively act on the bacterial 50S large ribosomal subunit to inhibit bacteria's protein elongation process by blocking the exit tunnel for the nascent peptide away from ribosome. The detailed molecular mechanism of macrolide binding is yet to be elucidated as it is currently known to the most general idea only. In this study, molecular dynamics (MD) simulation was employed to study their interaction at the molecular level, and the binding free energies for both systems were calculated using the molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) method. The calculated binding free energies for both systems were slightly overestimated compared to the experimental values, but individual energy terms enabled better understanding in the binding for both systems. Decomposition of results into residue basis was able to show the contribution of each residue at the binding pocket toward the binding affinity of macrolides and hence identified several key interacting residues that were in agreement with previous experimental and computational data. Results also indicated the contributions from van der Waals are more important and significant than electrostatic contribution in the binding of macrolides to the binding pocket. The findings from this study are expected to contribute to the understanding of a detailed mechanism of action in a quantitative matter and thus assisting in the development of a safer macrolide antibiotic.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry*
  2. Antibacterial activity of halogenated sesquiterpenes from Malaysian Laurencia spp
    Vairappan CS, Suzuki M, Ishii T, Okino T, Abe T, Masuda M
    Phytochemistry, 2008 Oct;69(13):2490-4.
    PMID: 18718619 DOI: 10.1016/j.phytochem.2008.06.015
    During our studies on Malaysian Laurencia species, brominated metabolites, tiomanene, acetylmajapolene B, and acetylmajapolene A were isolated from an unrecorded species collected at Pulau Tioman, Pahang along with known majapolene B and majapolene A. Acetylmajapolene A was a mixture of diastereomers as in the case of majapolene A. Tiomanene may be a plausible precursor for acetylmajapolenes B and A. In addition, three known halogenated sesquiterpenes and two known halogenated C(15) acetogenins were found from other two unrecorded species collected at Pulau Karah, Terengganu and Pulau Nyireh, Terengganu, respectively. Some of these halogenated metabolites showed moderate antibacterial activity against some marine bacteria.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry
  3. Refinement of a low-resolution crystal structure to better understand erythromycin interactions on large ribosomal subunit
    Wahab HA, Yam WK, Samian MR, Najimudin N
    J Biomol Struct Dyn, 2008 Aug;26(1):131-46.
    PMID: 18533733
    Macrolides are a group of diverse class of naturally occurring and synthetic antibiotics made of macrocyclic-lactone ring carrying one or more sugar moieties linked to various atoms of the lactone ring. These macrolides selectively bind to a single high affinity site on the prokaryotic 50S ribosomal subunit, making them highly effective towards a wide range of bacterial pathogens. The understanding of binding between macrolides and ribosome serves a good basis in elucidating how they work at the molecular level and these findings would be important in rational drug design. Here, we report refinement of reconstructed PDB structure of erythromycin-ribosome system using molecular dynamics (MD) simulation. Interesting findings were observed in this refinement stage that could improve the understanding of the binding of erythromycin A (ERYA) onto the 50S subunit. The results showed ERYA was highly hydrated and water molecules were found to be important in bridging hydrogen bond at the binding pocket during the simulation time. ERYA binding to ribosome was also strengthened by hydrogen bond network and hydrophobic interactions between the antibiotic and the ribosome. Our MD simulation also demonstrated direct interaction of ERYA with Domains II, V and with C1773 (U1782EC), a residue in Domain IV that has yet been described of its role in ERYA binding. It is hoped that this refinement will serve as a starting model for a further enhancement of our understanding towards the binding of ERYA to ribosome.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry
  4. A Review of Bisindolylmethane as an Important Scaffold for Drug Discovery
    Imran S, Taha M, Ismail NH
    Curr Med Chem, 2015;22(38):4412-33.
    PMID: 26438249
    Bisindolylmethane and its derivatives are pharmacologically active and applicable in the field of pharmaceutical chemistry. Bisindolylmethanes have a variety of biological activities such as antihyperglycemic, antiinflammatory, antibacterial, anticancer, and antileishmanial activities, including enzyme inhibition activity. They play a crucial role in many diseases especially anticancer activity. Modifying their structure had proven to be useful in the search of new therapeutic agents. Extensive research carried out on bisindolylmethane and its derivatives shows that they are pharmacologically significant. The present review focuses on the pharmacological profile of bisindolylmethane derivatives. This review includes the current literature with an update of research findings as well as the perspectives that they hold for future research.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry*
  5. Three new cembranoids from the Bornean soft coral Nephthea sp
    Ishii T, Kamada T, Vairappan CS
    J Asian Nat Prod Res, 2016 May;18(5):415-22.
    PMID: 26983053 DOI: 10.1080/10286020.2016.1145670
    Three new cembranoid diterpenes, 10-hydroxy-nephthenol acetate (1), 7,8-epoxy-10-hydroxy-nephthenol acetate (2), and 6-acetoxy-7,8-epoxy-10-hydroxy-nephthenol acetate (3), along with a known compound, 6-acetoxy-7,8-epoxy-nephthenol acetate (4), were isolated from the Bornean soft coral Nephthea sp. Antibacterial and anticancer activities were exhibited by compounds 1 and 2 against Staphylococcus aureus (ATCC 6538)/Escherichia coli (ATCC 13311) and Hela/MCF-7, respectively.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry
  6. New insight into the structural, electrochemical and biological aspects of macroacyclic Cu(II) complexes derived from S-substituted dithiocarbazate schiff bases
    Low ML, Maigre L, Tahir MI, Tiekink ER, Dorlet P, Guillot R, et al.
    Eur J Med Chem, 2016 Sep 14;120:1-12.
    PMID: 27183379 DOI: 10.1016/j.ejmech.2016.04.027
    Copper (II) complexes synthesized from the products of condensation of S-methyl- and S-benzyldithiocarbazate with 2,5-hexanedione (SMHDH2 and SBHDH2 respectively) have been characterized using various physicochemical (elemental analysis, molar conductivity, magnetic susceptibility) and spectroscopic (infrared, electronic) methods. The structures of SMHDH2, its copper (II) complex, CuSMHD, and the related CuSBHD complex as well as a pyrrole byproduct, SBPY, have been determined by single crystal X-ray diffraction. In order to provide more insight into the behaviour of the complexes in solution, electron paramagnetic resonance (EPR) and electrochemical experiments were performed. Antibacterial activity and cytotoxicity were evaluated. The compounds, dissolved in 0.5% and 5% DMSO, showed a wide range of antibacterial activity against 10 strains of Gram-positive and Gram-negative bacteria. Investigations of the effects of efflux pumps and membrane penetration on antibacterial activity are reported herein. Antiproliferation activity was observed to be enhanced by complexation with copper. Preliminary screening showed Cu complexes are strongly active against human breast adenocarcinoma cancer cell lines MDA-MB-231 and MCF-7.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry
  7. Antibacterial Labdane Diterpenoids from Vitex vestita
    Corlay N, Lecsö-Bornet M, Leborgne E, Blanchard F, Cachet X, Bignon J, et al.
    J Nat Prod, 2015 Jun 26;78(6):1348-56.
    PMID: 26034885 DOI: 10.1021/acs.jnatprod.5b00206
    A large-scale in vitro screening of tropical plants using an antibacterial assay permitted the selection of several species with significant antibacterial activities. Bioassay-guided purification of the dichloromethane extract of the leaves of the Malaysian species Vitex vestita, led to the isolation of six new labdane-type diterpenoids, namely, 12-epivitexolide A (2), vitexolides B and C (3 and 4), vitexolide E (8), and vitexolins A and B (5 and 6), along with six known compounds, vitexolides A (1) and D (7), acuminolide (9), 3β-hydroxyanticopalic acid (10), 8α-hydroxyanticopalic acid (11), and 6α-hydroxyanticopalic acid (12). Their structures were elucidated on the basis of 1D and 2D NMR analyses and HRMS experiments. Both variable-temperature NMR spectroscopic studies and chemical modifications were performed to investigate the dynamic epimerization of the γ-hydroxybutenolide moiety of compounds 1-4. Compounds were assayed against a panel of 46 Gram-positive strains. Vitexolide A (1) exhibited the most potent antibacterial activity with minimal inhibitory concentration values ranging from 6 to 96 μM, whereas compounds 2 and 6-9 showed moderate antibacterial activity. The presence of a β-hydroxyalkyl-γ-hydroxybutenolide subunit contributed significantly to antibacterial activity. Compounds 1-4 and 6-9 showed cytotoxic activities against the HCT-116 cancer cell line (1 < IC50s < 10 μM) and human fetal lung fibroblast MRC5 cell line (1 < IC50s < 10 μM for compounds 1, 2, 7, 8, and 9).
    Matched MeSH terms: Anti-Bacterial Agents/chemistry
  8. Novel halogenated metabolites from the Malaysian Laurencia pannosa
    Suzuki M, Daitoh M, Vairappan CS, Abe T, Masuda M
    J Nat Prod, 2001 May;64(5):597-602.
    PMID: 11374951
    In connection with our chemotaxonomic studies of Malaysian species of the red algal genus Laurencia, the chemical composition of Laurencia pannosa Zanardini was examined. Two halogenated sesquiterpenoids, named pannosanol (1) and pannosane (2), have been isolated along with a halogenated C15-acetogenin, (3Z)-chlorofucin (3). The structures of these compounds were determined from their spectroscopic data (IR, 1H NMR, 13C NMR, 2D NMR, and MS). Pannosanol and pannosane are novel halometabolites with an unusual rearranged chamigrane framework. Antibacterial activities of these metabolites against marine bacteria are also described.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry*
  9. Investigation of the antibacterial activity of Ag-NPs conjugated with a specific antibody against Staphylococcus aureus after photoactivation
    Al-Sharqi A, Apun K, Vincent M, Kanakaraju D, Bilung LM, Sum MSH
    J Appl Microbiol, 2020 Jan;128(1):102-115.
    PMID: 31596989 DOI: 10.1111/jam.14471
    AIM: This work reports a new method for the use of lasers for the selective killing of bacteria targeted using light-absorbing Silver nanoparticles (Ag-NPs) conjugated with a specific antibody against the Gram-positive bacterium Staphylococcus aureus (S. aureus).

    METHODS AND RESULTS: Ag-NPs were synthesized using a chemical reduction method and characterized with respect to their surface plasmon resonance, surface morphology via transmission electron microscopy (TEM) and dynamic light scattering (DLS). The bacterial surface was targeted using 20 nm Ag-NPs conjugated with an anti-protein A antibody. Labelled bacteria were irradiated with blue visible laser at 2·04 W/cm2 . The antibacterial activity of functionalized Ag-NPs was investigated by fluorescence microscopy after irradiation, and morphological changes in S. aureus after laser treatment were assessed using scanning electron microscopy (SEM). The laser-irradiated, functionalized Ag-NPs exhibited significant bactericidal activity, and laser-induced bacterial damage was observed after 10 min of laser irradiation against S. aureus. The fluorescence microscopic analysis results supported that bacterial cell death occurred in the presence of the functionalized Ag-NPs.

    CONCLUSIONS: The results of this study suggest that a novel method for the preparation of functionalized nanoparticles has potential as a potent antibacterial agent for the selective killing of resistant disease-causing bacteria.

    SIGNIFICANCE AND IMPACT OF THE STUDY: This study shows that Ag-NPs functionalized with a specific antibody, could be used in combination with laser radiation as a novel treatment to target resistant bacterial and fungal pathogens with minimal impact on normal microflora.

    Matched MeSH terms: Anti-Bacterial Agents/chemistry
  10. Fulltext Effect of Propolis Nanoparticles against Enterococcus faecalis Biofilm in the Root Canal
    Parolia A, Kumar H, Ramamurthy S, Madheswaran T, Davamani F, Pichika MR, et al.
    Molecules, 2021 Jan 30;26(3).
    PMID: 33573147 DOI: 10.3390/molecules26030715
    To determine the antibacterial effect of propolis nanoparticles (PNs) as an endodontic irrigant against Enterococcus faecalis biofilm inside the endodontic root canal system. Two-hundred-ten extracted human teeth were sectioned to obtain 6 mm of the middle third of the root. The root canal was enlarged to an internal diameter of 0.9 mm. The specimens were inoculated with E. faecalis for 21 days. Following this, specimens were randomly divided into seven groups, with 30 dentinal blocks in each group including: group I-saline; group II-propolis 100 µg/mL; group III-propolis 300 µg/mL; group IV-propolis nanoparticle 100 µg/mL; group V-propolis nanoparticle 300µg/mL; group VI-6% sodium hypochlorite; group VII-2% chlorhexidine. Dentin shavings were collected at 200 and 400 μm depths, and total numbers of CFUs were determined at the end of one, five, and ten minutes. The non-parametric Kruskal-Wallis and Mann-Whitney tests were used to compare the differences in reduction in CFUs between all groups, and probability values of p < 0.05 were set as the reference for statistically significant results. The antibacterial effect of PNs as an endodontic irrigant was also assessed against E. faecalis isolates from patients with failed root canal treatment. Scanning electron microscopy (SEM) and confocal laser scanning microscopy (CLSM) were also performed after exposure to PNs. A Raman spectroscope, equipped with a Leica microscope and lenses with curve-fitting Raman software, was used for analysis. The molecular interactions between bioactive compounds of propolis (Pinocembrin, Kaempferol, and Quercetin) and the proteins Sortase A and β-galactosidase were also understood by computational molecular docking studies. PN300 was significantly more effective in reducing CFUs compared to all other groups (p < 0.05) except 6% NaOCl and 2% CHX (p > 0.05) at all time intervals and both depths. At five minutes, 6% NaOCl and 2% CHX were the most effective in reducing CFUs (p < 0.05). However, no significant difference was found between PN300, 6% NaOCl, and 2% CHX at 10 min (p > 0.05). SEM images also showed the maximum reduction in E. faecalis with PN300, 6% NaOCl, and 2% CHX at five and ten minutes. CLSM images showed the number of dead cells in dentin were highest with PN300 compared to PN100 and saline. There was a reduction in the 484 cm-1 band and an increase in the 870 cm-1 band in the PN300 group. The detailed observations of the docking poses of bioactive compounds and their interactions with key residues of the binding site in all the three docking protocols revealed that the interactions were consistent with reasonable docking and IFD docking scores. PN300 was equally as effective as 6% NaOCl and 2% CHX in reducing the E. faecalis biofilms.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry
  11. Molecularly imprinted silica gel incorporated with agarose polymer matrix as mixed matrix membrane for separation and preconcentration of sulfonamide antibiotics in water samples
    Rozaini MNH, Semail NF, Saad B, Kamaruzaman S, Abdullah WN, Rahim NA, et al.
    Talanta, 2019 Jul 01;199:522-531.
    PMID: 30952293 DOI: 10.1016/j.talanta.2019.02.096
    Molecularly imprinted silica gel (MISG) was incorporated through dispersion in agarose polymer matrix to form a mixed matrix membrane (MMM) and was applied for the determination of three sulfonamide antibiotic compounds (i.e. sulfamethoxazole (SMX), sulfamonomethoxine (SMM), and sulfadiazine (SDZ)) from environmental water samples. Several important microextraction conditions, such as type of desorption solvent, extraction time, amount of sorbent, sample volume, pH, and effect of desorption time, were comprehensively optimized. A preconcentration factors of ≥ 20 was achieved by the extraction of 12.5 mL of water samples using the developed method. This microextraction-HPLC method demonstrated good linearity (1-500 μg L-1) with a coefficient of determination (R2) of 0.9959-0.9999, low limits of detection (0.06-0.17 μg L-1) and limits of quantification (0.20-0.56 μg L-1), good analyte recoveries (80-96%), and acceptable relative standard deviations (< 10%) under the optimized conditions. The method is systematically compared to those reported in the literature.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry
  12. D-glucosamine chitosan base molecule-assisted synthesis of different shape and sized silver nanoparticles by a single pot method: A greener approach for sensor and microbial applications
    Ranjani B, Pandian K, Kumar GA, Gopinath SCB
    Int J Biol Macromol, 2019 Jul 15;133:1280-1287.
    PMID: 31051204 DOI: 10.1016/j.ijbiomac.2019.04.196
    Silver nanoparticle was synthesized using D-glucosamine chitosan base as green reducing agent at elevated temperature in alkaline pH ranges. The excess of D-glucosamine chitosan base was used as it is both stabilizing and reducing agent at different pHs, regulates the shape and size of the silver nanoparticles. The progressive growth of silver nanoparticles was monitored by UV-Visible spectral studies. A sharp peak at 420 nm indicates the formation of spherical silver nanoparticles. The size and shape of silver nanoparticles were observed from Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) methods. The anisotropically grown nanoparticles were used as probe for Surface Enhanced Raman Studies (SERS) using ATP (4-aminothiophenol) as a model system. The catalytic behavior of silver nanoparticles was exploited for 4-nitrophenol reduction and observed that the reduction reaction follows pseudo first order kinetics with a rate constant 0.65 min. The antibacterial activity of silver nanoparticles was also tested for both gram-positive and -negative microorganisms, in which higher zone of inhibition was observed for gram negative microorganism.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry
  13. Fulltext Enhanced Pharmaceutically Active Compounds Productivity from Streptomyces SUK 25: Optimization, Characterization, Mechanism and Techno-Economic Analysis
    Al-Shaibani MM, Radin Mohamed RMS, Zin NM, Al-Gheethi A, Al-Sahari M, El Enshasy HA
    Molecules, 2021 Apr 25;26(9).
    PMID: 33923072 DOI: 10.3390/molecules26092510
    The present research aimed to enhance the pharmaceutically active compounds' (PhACs') productivity from Streptomyces SUK 25 in submerged fermentation using response surface methodology (RSM) as a tool for optimization. Besides, the characteristics and mechanism of PhACs against methicillin-resistant Staphylococcus aureus were determined. Further, the techno-economic analysis of PhACs production was estimated. The independent factors include the following: incubation time, pH, temperature, shaker rotation speed, the concentration of glucose, mannitol, and asparagine, although the responses were the dry weight of crude extracts, minimum inhibitory concentration, and inhibition zone and were determined by RSM. The PhACs were characterized using GC-MS and FTIR, while the mechanism of action was determined using gene ontology extracted from DNA microarray data. The results revealed that the best operating parameters for the dry mass crude extracts production were 8.20 mg/L, the minimum inhibitory concentrations (MIC) value was 8.00 µg/mL, and an inhibition zone of 17.60 mm was determined after 12 days, pH 7, temperature 28 °C, shaker rotation speed 120 rpm, 1 g glucose /L, 3 g mannitol/L, and 0.5 g asparagine/L with R2 coefficient value of 0.70. The GC-MS and FTIR spectra confirmed the presence of 21 PhACs, and several functional groups were detected. The gene ontology revealed that 485 genes were upregulated and nine genes were downregulated. The specific and annual operation cost of the production of PhACs was U.S. Dollar (U.S.D) 48.61 per 100 mg compared to U.S.D 164.3/100 mg of the market price, indicating that it is economically cheaper than that at the market price.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry
  14. Dye degradation, antibacterial and in-silico analysis of Mg/cellulose-doped ZnO nanoparticles
    Ikram M, Mahmood A, Haider A, Naz S, Ul-Hamid A, Nabgan W, et al.
    Int J Biol Macromol, 2021 Aug 31;185:153-164.
    PMID: 34157328 DOI: 10.1016/j.ijbiomac.2021.06.101
    Various concentrations of Mg into fixed amount of cellulose nanocrystals (CNC)-doped ZnO were synthesized using facile chemical precipitation. The aim of present study is to remove dye degradation of methylene blue (MB) and bactericidal behavior with synthesized product. Phase constitution, functional group analysis, optical behavior, elemental composition, morphology and microstructure were examined using XRD, FTIR, UV-Vis spectrophotometer, EDS and HR-TEM. Highly efficient photocatalytic performance was observed in basic medium (98%) relative to neutral (65%), and acidic (83%) was observed upon Mg and CNC co-doping. Significant bactericidal activity of doped ZnO nanoparticles depicted inhibition zones for G -ve and +ve bacteria ranging (2.20 - 4.25 mm) and (5.80-7.25 mm) for E. coli and (1.05 - 2.75 mm) and (2.80 - 4.75 mm) for S. aureus at low and high doses, respectively. Overall, doped nanostructures showed significant (P 
    Matched MeSH terms: Anti-Bacterial Agents/chemistry
  15. Antibacterial efficacy of poly(hexamethylene biguanide) immobilized on chitosan/dye-modified nanofiber membranes
    Xu FX, Ooi CW, Liu BL, Song CP, Chiu CY, Wang CY, et al.
    Int J Biol Macromol, 2021 Jun 30;181:508-520.
    PMID: 33775766 DOI: 10.1016/j.ijbiomac.2021.03.151
    This study aimed to develop a novel electrospun polyacrylonitrile (PAN) nanofiber membrane with the enhanced antibacterial property. The PAN nanofiber membrane was first subjected to alkaline hydrolysis treatment, and the treated membrane was subsequently grafted with chitosan (CS) to obtain a CS-modified nanofiber membrane (P-COOH-CS). The modified membrane was then coupled with different dye molecules to form P-COOH-CS-Dye membranes. Lastly, poly(hexamethylene biguanide) hydrochloride (PHMB) was immobilized on the modified membrane to produce P-COOH-CS-Dye-PHMB. Physical characterization studies were conducted on all the synthesized nanofiber membranes. The antibacterial efficacies of nanofiber membranes prepared under different synthesis conditions were evaluated systematically. Under the optimum synthesis conditions, P-COOH-CS-Dye-PHMB was highly effective in disinfecting a high concentration of Escherichia coli, with an antibacterial efficacy of approximately 100%. Additionally, the P-COOH-CS-Dye-PHMB exhibited an outstanding wash durability as its antibacterial efficacy was only reduced in the range of 5%-7% even after 5 repeated cycles of treatment. Overall, the experimental results of this study suggested that the P-COOH-CS-Dye-PHMB is a promising antibacterial nanofiber membrane that can be adopted in the food, pharmaceutical, and textile industries.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry
  16. Superhydrophobic nanocarbon-based membrane with antibacterial characteristics
    Aljumaily MM, Alsaadi MA, Binti Hashim NA, Mjalli FS, Alsalhy QF, Khan AL, et al.
    Biotechnol Prog, 2020 05;36(3):e2963.
    PMID: 31943942 DOI: 10.1002/btpr.2963
    To overcome the biofouling challenge which faces membrane water treatment processed, the novel superhydrophobic carbon nanomaterials impregnated on/powder activated carbon (CNMs/PAC) was utilized to successfully design prepare an antimicrobial membrane. The research was conducted following a systematic statistical design of experiments technique considering various parameters of composite membrane fabrication. The impact of these parameters of composite membrane on Staphylococcus aureus growth was investigated. The bacteria growth was analyzed through spectrophotometer and SEM. The effect of CNMs' hydrophobicity on the bacterial colonies revealed a decrease in the abundance of bacterial colonies and an alteration in structure with increasing the hydrophobicity. The results revealed that the optimum preparative conditions for carbon loading CNMs/PAC was 363.04 mg with a polymer concentration of 22.64 g/100 g, and a casting knife thickness of 133.91 μm. These conditions have resulted in decreasing the number of bacteria colonies to about 7.56 CFU. Our results provided a strong evidence on the antibacterial effect and consequently on the antibiofouling potential of CNMs/PAC in membrane.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry*
  17. Preparation and photodynamic bactericidal effects of curcumin-β-cyclodextrin complex
    Lai D, Zhou A, Tan BK, Tang Y, Sarah Hamzah S, Zhang Z, et al.
    Food Chem, 2021 Nov 01;361:130117.
    PMID: 34058659 DOI: 10.1016/j.foodchem.2021.130117
    To overcome the poor water solubility of curcumin, a curcumin-β-cyclodextrin (Cur-β-CD) complex was prepared as a novel photosensitizer. Fourier-transform infrared spectroscopy (FT-IR), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) were used to verify the formation of Cur-β-CD. Furthermore, the ROS generation capacity and photodynamic bactericidal effect were measured to confirm this Cur-β-CD complex kept photodynamic activity of curcumin. The result showed Cur-β-CD could effectively generate ROS upon blue-light irradiation. The plate count assay demonstrated Cur-β-CD complex possess desirable photodynamic antibacterial effect against food-borne pathogens including Staphylococcus aureus, Listeria monocytogenes and Escherichia coli. The cell morphology determined by scanning electron microscope (SEM) and transmission electron microscope (TEM) showed Cur-β-CD could cause cell deformation, surface collapse and cell structure damage of the bacteria, resulting in the leakage of cytoplasmic; while agarose gel electrophoresis and SDS-PAGE further illustrated the inactivation mechanisms by Cur-β-CD involve bacterial DNA damage and protein degradation.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry*
  18. Synthesis and biological evaluation of indole core-based derivatives with potent antibacterial activity against resistant bacterial pathogens
    Hong W, Li J, Chang Z, Tan X, Yang H, Ouyang Y, et al.
    J Antibiot (Tokyo), 2017 Jul;70(7):832-844.
    PMID: 28465626 DOI: 10.1038/ja.2017.55
    The emergence of drug resistance in bacterial pathogens is a growing clinical problem that poses difficult challenges in patient management. To exacerbate this problem, there is currently a serious lack of antibacterial agents that are designed to target extremely drug-resistant bacterial strains. Here we describe the design, synthesis and antibacterial testing of a series of 40 novel indole core derivatives, which are predicated by molecular modeling to be potential glycosyltransferase inhibitors. Twenty of these derivatives were found to show in vitro inhibition of Gram-positive bacteria, including methicillin-resistant Staphylococcus aureus. Four of these strains showed additional activity against Gram-negative bacteria, including extended-spectrum beta-lactamase producing Enterobacteriaceae, imipenem-resistant Klebsiella pneumoniae and multidrug-resistant Acinetobacter baumanii, and against Mycobacterium tuberculosis H37Ra. These four compounds are candidates for developing into broad-spectrum anti-infective agents.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry
  19. Fulltext Bactericidal Effect of Pterostilbene Alone and in Combination with Gentamicin against Human Pathogenic Bacteria
    Lee WX, Basri DF, Ghazali AR
    Molecules, 2017 Mar 17;22(3).
    PMID: 28304328 DOI: 10.3390/molecules22030463
    The antibacterial activity of pterostilbene in combination with gentamicin against six strains of Gram-positive and Gram-negative bacteria were investigated. The minimum inhibitory concentration and minimum bactericidal concentration of pterostilbene were determined using microdilution technique whereas the synergistic antibacterial activities of pterostilbene in combination with gentamicin were assessed using checkerboard assay and time-kill kinetic study. Results of the present study showed that the combination effects of pterostilbene with gentamicin were synergistic (FIC index < 0.5) against three susceptible bacteria strains: Staphylococcus aureus ATCC 25923, Escherichia coli O157 and Pseudomonas aeruginosa 15442. However, the time-kill study showed that the interaction was indifference which did not significantly differ from the gentamicin treatment. Furthermore, time-kill study showed that the growth of the tested bacteria was completely attenuated with 2 to 8 h treatment with 0.5 × MIC of pterostilbene and gentamicin. The identified combinations could be of effective therapeutic value against bacterial infections. These findings have potential implications in delaying the development of bacterial resistance as the antibacterial effect was achieved with the lower concentrations of antibacterial agents.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry
  20. Fulltext Alpha-Mangostin-Rich Extracts from Mangosteen Pericarp: Optimization of Green Extraction Protocol and Evaluation of Biological Activity
    Ghasemzadeh A, Jaafar HZE, Baghdadi A, Tayebi-Meigooni A
    Molecules, 2018 Jul 25;23(8).
    PMID: 30044450 DOI: 10.3390/molecules23081852
    Since α-mangostin in mangosteen fruits was reported to be the main compound able to provide natural antioxidants, the microwave-assisted extraction process to obtain high-quality α-mangostin from mangosteen pericarp (Garcinia mangostana L.) was optimized using a central composite design and response surface methodology. The parameters examined included extraction time, microwave power, and solvent percentage. The antioxidant and antimicrobial activity of optimized and non-optimized extracts was evaluated. Ethyl acetate as a green solvent exhibited the highest concentration of α-mangostin, followed by dichloromethane, ethanol, and water. The highest α-mangostin concentration in mangosteen pericarp of 121.01 mg/g dry matter (DM) was predicted at 3.16 min, 189.20 W, and 72.40% (v/v). The verification of experimental results under these optimized conditions showed that the α-mangostin value for the mangosteen pericarp was 120.68 mg/g DM. The predicted models were successfully developed to extract α-mangostin from the mangosteen pericarp. No significant differences were observed between the predicted and the experimental α-mangostin values, indicating that the developed models are accurate. The analysis of the extracts for secondary metabolites showed that the total phenolic content (TPC) and total flavonoid content (TFC) increased significantly in the optimized extracts (OE) compared to the non-optimized extracts (NOE). Additionally, trans-ferulic acid and catechin were abundant among the compounds identified. In addition, the optimized extract of mangosteen pericarp with its higher α-mangostin and secondary metabolite concentrations exhibited higher antioxidant activities with half maximal inhibitory concentration (IC50) values of 20.64 µg/mL compared to those of the NOE (28.50 µg/mL). The OE exhibited the highest antibacterial activity, particularly against Gram-positive bacteria. In this study, the microwave-assisted extraction process of α-mangostin from mangosteen pericarp was successfully optimized, indicating the accuracy of the models developed, which will be usable in a larger-scale extraction process.
    Matched MeSH terms: Anti-Bacterial Agents/chemistry*
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