Displaying publications 21 - 40 of 86 in total

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  1. Antibacterial and antioxidant activity of naphthofuranquinones from the twigs of tropical mangrove Avicennia officinalis
    Assaw S, Mohd Amir MIH, Khaw TT, Bakar K, Mohd Radzi SA, Mazlan NW
    Nat Prod Res, 2020 Aug;34(16):2403-2406.
    PMID: 30600710 DOI: 10.1080/14786419.2018.1538220
    Mangrove plants are endowed with various biologically active compounds which have potent antibacterial and antioxidant properties. In present study, a bioactivity-guided fractionation for antibacterial and antioxidant active metabolites from the twigs of Avicennia officinalis collected from Kuala Selangor Nature Park, Selangor, Malaysia gave 13 major fractions. The antibacterial activity of A. officinalis fractions using well-diffusion showed strong selectivity on the Gram-positive bacteria (Staphylococcus epidermidis, S. aureus and Bacillus subtilis) with minimum inhibition concentration (MIC) values of 0.156-5.00 mg/mL. However, no antibacterial activities were observed on the Gram-negative bacteria (Vibrio cholera, Enterobacter cloacae and Escherichia coli). The active antibacterial fractions were further isolated using several chromatographic techniques to give two naphthofuranquinones, namely, avicenol C (1) and stenocarpoquinone B (2). Meanwhile, the antioxidant activity of A. officinalis fractions were evaluated using DPPH radical scavenging assay exhibited low antioxidant activities. Molecular structure of the naphthofuranquinones was elucidated using 1 D and 2 D NMR spectroscopy.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects
  2. Gut bacteria of cockroaches are a potential source of antibacterial compound(s)
    Akbar N, Siddiqui R, Iqbal M, Sagathevan K, Khan NA
    Lett Appl Microbiol, 2018 May;66(5):416-426.
    PMID: 29457249 DOI: 10.1111/lam.12867
    Here, we hypothesized that the microbial gut flora of animals/pests living in polluted environments, produce substances to thwart bacterial infections. The overall aim of this study was to source microbes inhabiting unusual environmental niches for potential antimicrobial activity. Two cockroach species, Gromphadorhina portentosa (Madagascar) and Blaptica dubia (Dubia) were selected. The gut bacteria from these species were isolated and grown in RPMI 1640 and conditioned media were prepared. Conditioned media were tested against a panel of Gram-positive (Methicillin-resistant Staphylococcus aureus, Streptococcus pyogenes, Bacillus cereus) and Gram-negative (Escherichia coli K1, Salmonella enterica, Serratia marcescens, Pseudomonas aeruginosa, Klebsiella pneumoniae) bacteria, as well as the protist pathogen, Acanthamoeba castellanii. The results revealed that the gut bacteria of cockroaches produce active molecule(s) with potent antibacterial properties, as well as exhibit antiamoebic effects. However, heat-inactivation at 95°C for 10 min had no effect on conditioned media-mediated antibacterial and antiamoebic properties. These results suggest that bacteria from novel sources i.e. from the cockroach's gut produce molecules with bactericidal as well as amoebicidal properties that can ultimately lead to the development of therapeutic drugs.

    SIGNIFICANCE AND IMPACT OF THE STUDY: The bacteria isolated from unusual dwellings such as the cockroaches' gut are a useful source of antibacterial and antiamoebal molecules. These are remarkable findings that will open several avenues in our search for novel antimicrobials from unique sources. Furthermore studies will lead to the identification of molecules to develop future antibacterials from insects.

    Matched MeSH terms: Gram-Negative Bacteria/drug effects*
  3. Epidemiology and trends in the antibiotic susceptibilities of Gram-negative bacilli isolated from patients with intra-abdominal infections in the Asia-Pacific region, 2010-2013
    Chang YT, Coombs G, Ling T, Balaji V, Rodrigues C, Mikamo H, et al.
    Int J Antimicrob Agents, 2017 Jun;49(6):734-739.
    PMID: 28435019 DOI: 10.1016/j.ijantimicag.2017.01.030
    This study was conducted to investigate the epidemiology and antimicrobial susceptibility patterns of Gram-negative bacilli (GNB) isolated from intra-abdominal infections (IAIs) in the Asia-Pacific region (APR) from 2010-2013. A total of 17 350 isolates were collected from 54 centres in 13 countries in the APR. The three most commonly isolated GNB were Escherichia coli (46.1%), Klebsiella pneumoniae (19.3%) and Pseudomonas aeruginosa (9.8%). Overall, the rates of extended-spectrum β-lactamase (ESBL)-producing E. coli and K. pneumoniae were 38.2% and 24.3%, respectively, and they were highest in China (66.6% and 38.7%, respectively), Thailand (49.8% and 36.5%, respectively) and Vietnam (47.9% and 30.4%, respectively). During 2010-2013, the rates of ESBL-producing E. coli and K. pneumoniae isolates causing community-associated (CA) IAIs (collected <48 h after admission) were 26.0% and 13.5%, respectively, and those causing hospital-associated (HA) IAIs were 48.0% and 30.6%, respectively. Amikacin, ertapenem and imipenem were the most effective agents against ESBL-producing isolates. Piperacillin/tazobactam displayed good in vitro activity (91.4%) against CA ESBL-producing E. coli. For other commonly isolated Enterobacteriaceae, fluoroquinolones, cefepime and carbapenems exhibited better in vitro activities than third-generation cephalosporins. Amikacin possessed high in vitro activity against all GNB isolates (>80%) causing IAIs, except for Acinetobacter calcoaceticus-baumannii (ACB) complex (30.9% for HA-IAI isolates). All of the antimicrobial agents tested exhibited <45% in vitro activity against ACB complex. Antimicrobial resistance is a persistent threat in the APR and continuous monitoring of evolutionary trends in the susceptibility patterns of GNB causing IAIs in this region is mandatory.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects*
  4. 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: Gram-Negative Bacteria/drug effects*
  5. 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: Gram-Negative Bacteria/drug effects
  6. Synergistic antibacterial actions of graphene oxide and antibiotics towards bacteria and the toxicological effects of graphene oxide on human epidermal keratinocytes
    Pulingam T, Thong KL, Appaturi JN, Nordin NI, Dinshaw IJ, Lai CW, et al.
    Eur J Pharm Sci, 2020 Jan 15;142:105087.
    PMID: 31626968 DOI: 10.1016/j.ejps.2019.105087
    Graphene oxide (GO) has displayed antibacterial activity that has been investigated in the past, however, information on synergistic activity of GO with conventional antibiotics is still lacking. The objectives of the study were to determine the combinatorial actions of GO and antibiotics against Gram-positive and Gram-negative bacteria and the toxicological effects of GO towards human epidermal keratinocytes (HaCaT). Interactions at molecular level between GO and antibiotics were analyzed using Attenuated Total Reflectance-Fourier-transform infrared spectroscopy (ATR-FTIR). Changes in the antibacterial activity of antibiotics towards bacteria through the addition of GO was investigated. Toxicity of GO towards HaCaT cells were examined as skin cells play a role as the first line of defense of the human body. The ATR-FTIR characterizations of GO and antibiotics showed adsorption of tested antibiotics onto GO. The combinatorial antibacterial activity of GO and antibiotics were found to increase when compared to GO or antibiotic alone. This was attributed to the ability of GO to disrupt bacterial membrane to allow for better adsorption of antibiotics. Cytotoxicity of GO was found to be dose-dependent towards HaCaT cell line, it is found to impose negligible toxic effects against the skin cells at concentration below 100 μg/mL.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects*
  7. Antimicrobial Exploration Between Counterpart Endosymbiont and Host Plant (Tamarindus indica Linn.)
    Chigurupati S, Vijayabalan S, Selvarajan KK, Aldubayan M, Alhowail A, Mani V, et al.
    Curr Pharm Biotechnol, 2020;21(5):384-389.
    PMID: 31657678 DOI: 10.2174/1389201020666191028105325
    BACKGROUND: Endophytic bacteria produce various bioactive secondary metabolites, which benefit human health. Tamarindus indica L. is well known for its medicinal value in human health care. Several studies have reported on its biological effects from various parts of T. indica, but only a few studies have been devoted to examining the biological activity of endophytes of T. indica.

    OBJECTIVES: In the present study, an endophyte was isolated from the leaves of T. indica and screened for its antimicrobial potential.

    METHODS: The selected endophyte was identified by 16s rRNA partial genome sequencing and investigated for their antimicrobial potency. The preliminary phytochemical tests were conducted for the affirmation of phytoconstituents in the endophytic crude ethyl acetate extract of T. indica (TIM) and total phenolic content was performed. The antimicrobial potential of TIM was evaluated against human pathogenic ATCC gram-positive and gram-negative bacterial strains.

    RESULTS: TIM exhibited an appreciable amount of gallic acid equivalent phenolic content (21.6 ± 0.04 mg GAE/g of crude extract). TIM showed the Minimum Inhibitory Concentration (MIC) at 250 μg/mL and Minimum Bactericidal Concentration (MBC) at 500 μg/mL among the selected human pathogenic ATCC strains. At MIC of 500 μg/mL, TIM displayed a significant zone of inhibition against P. aeruginosa and N. gonorrhoeae.

    CONCLUSION: The results from our study highlighted for the first time the antimicrobial potential of endophytic bacterial strain Bacillus velezensis in T. indica leaves and it could be further explored as a source of natural antimicrobial agents.

    Matched MeSH terms: Gram-Negative Bacteria/drug effects
  8. Fulltext Antimycobacterial, antimicrobial, and biocompatibility properties of para-aminosalicylic acid with zinc layered hydroxide and Zn/Al layered double hydroxide nanocomposites
    Saifullah B, El Zowalaty ME, Arulselvan P, Fakurazi S, Webster TJ, Geilich BM, et al.
    Drug Des Devel Ther, 2014;8:1029-36.
    PMID: 25114509 DOI: 10.2147/DDDT.S63753
    The treatment of tuberculosis by chemotherapy is complicated due to multiple drug prescriptions, long treatment duration, and adverse side effects. We report here for the first time an in vitro therapeutic effect of nanocomposites based on para-aminosalicylic acid with zinc layered hydroxide (PAS-ZLH) and zinc-aluminum layered double hydroxides (PAS-Zn/Al LDH), against mycobacteria, Gram-positive bacteria, and Gram-negative bacteria. The nanocomposites demonstrated good antimycobacterial activity and were found to be effective in killing Gram-positive and Gram-negative bacteria. A biocompatibility study revealed good biocompatibility of the PAS-ZLH nanocomposites against normal human MRC-5 lung cells. The para-aminosalicylic acid loading was quantified with high-performance liquid chromatography analysis. In summary, the present preliminary in vitro studies are highly encouraging for further in vivo studies of PAS-ZLH and PAS-Zn/Al LDH nanocomposites to treat tuberculosis.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects
  9. Fulltext Synthesis of novel bisindolylmethane Schiff bases and their antibacterial activity
    Imran S, Taha M, Ismail NH, Khan KM, Naz F, Hussain M, et al.
    Molecules, 2014;19(8):11722-40.
    PMID: 25102118 DOI: 10.3390/molecules190811722
    In an effort to develop new antibacterial drugs, some novel bisindolylmethane derivatives containing Schiff base moieties were prepared and screened for their antibacterial activity. The synthesis of the bisindolylmethane Schiff base derivatives 3-26 was carried out in three steps. First, the nitro group of 3,3'-((4-nitrophenyl)-methylene)bis(1H-indole) (1) was reduced to give the amino substituted bisindolylmethane 2 without affecting the unsaturation of the bisindolylmethane moiety using nickel boride in situ generated. Reduction of compound 1 using various catalysts showed that combination of sodium borohydride and nickel acetate provides the highest yield for compound 2. Bisindolylmethane Schiff base derivatives were synthesized by coupling various benzaldehydes with amino substituted bisindolylmethane 2. All synthesized compounds were characterized by various spectroscopic methods. The bisindolylmethane Schiff base derivatives were evaluated against selected Gram-positive and Gram-negative bacterial strains. Derivatives having halogen and nitro substituent display weak to moderate antibacterial activity against Salmonella typhi, S. paratyphi A and S. paratyphi B.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects*
  10. Oritavancin - a new semisynthetic lipoglycopeptide agent to tackle the challenge of resistant gram positive pathogens
    Das B, Sarkar C, Schachter J
    Pak J Pharm Sci, 2013 Sep;26(5):1045-55.
    PMID: 24035967
    Natural glycopeptide antibiotics like vancomycin and teicoplanin have played a significant role in countering the threat posed by Gram-positive bacterial infections. The emergence of resistance to glycopeptides among enterococci and staphylococci has prompted the search for second-generation drugs of this class and semi-synthetic derivatives are currently under clinical trials. Antimicrobial resistance among Gram-positive organisms has been increasing steadily during the past several decades and the current development of antibiotics falls short of meeting the needs. Oritavancin (LY-333328 diphosphate), a promising novel second-generation semisynthetic lipoglycopeptide, has a mechanism of action similar to that of other glycopeptides. It has concentration-dependent activity against a variety of Gram-positive organisms specially methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-intermediate resistant Staphylococcus aureus (VISA), Streptococcus pneumoniae and vancomycin-resistant enterococcus. It is rapidly bactericidal against many species and in particular for enterococci where vancomycin and teicoplanin are only bacteriostatic even against susceptible strains. The pharmacokinetic profile of oritavancin has not been fully described; however, oritavancin has a long half-life of about 195.4 hours and is slowly eliminated by renal means. Oritavancin is not metabolized by the liver in animals. Oritavancin will most probably be prescribed as a once-daily dose and it demonstrates concentration-dependent bactericidal activity. Oritavancin has demonstrated preliminary safety and efficacy in Phase I and II clinical trials. In a Phase III clinical trial, oritavancin has achieved the primary efficacy end point in the treatment of complicated Gram-positive skin and skin-structure infections. To date, adverse events have been mild and limited; the most common being administration site complaints, headache, rhinitis, dry skin, pain, increases in liver transaminases and accumulation of free cholesterol and phospholipids in phagocytic (macrophages) and nonphagocytic (fibroblast) cells. Oritavancin appears to be a promising antimicrobial alternative to vancomycin (with additional activity against Staphylococcus and Enterococcus resistant to vancomycin) for the treatment of complicated Gram-positive skin and skin-structure infections. Additional clinical data are required to fully explore its use.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects*
  11. Fulltext Heteroaryl chalcones: design, synthesis, X-ray crystal structures and biological evaluation
    Kumar CS, Loh WS, Ooi CW, Quah CK, Fun HK
    Molecules, 2013 Oct 15;18(10):12707-24.
    PMID: 24132195 DOI: 10.3390/molecules181012707
    Chalcone derivatives have attracted increasing attention due to their numerous pharmacological activities. Changes in their structures have displayed high degree of diversity that has proven to result in a broad spectrum of biological activities. The present study highlights the synthesis of some halogen substituted chalcones 3(a-i) containing the 5-chlorothiophene moiety, their X-ray crystal structures and the evaluation of possible biological activities such as antibacterial, antifungal and reducing power abilities. The results indicate the tested compounds show a varied range of inhibition values against all the tested microbial strains. Compound 3c with a p-fluoro substituent on the phenyl ring exhibits elevated antimicrobial activity, whereas the compounds 3e and 3f displayed the least antimicrobial activities. The compounds 3d, 3e, 3f and 3i showed good ferric and cupric reducing abilities, and the compounds 3b and 3c showed the weakest reducing power in the series.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects
  12. Fulltext Acute toxicity evaluation, antibacterial, antioxidant and immunomodulatory effects of Melastoma malabathricum
    Alnajar ZA, Abdulla MA, Ali HM, Alshawsh MA, Hadi AH
    Molecules, 2012;17(3):3547-59.
    PMID: 22433579 DOI: 10.3390/molecules17033547
    Melastoma malabathricum (MM) is a well-known plant in Malaysian traditional medicine, locally known as senduduk. Its ethanol and aqueous extracts have been used in the present investigation to study the immunomodulatory role on human peripheral blood mononuclear cell (PBMC), and the DPPH, ABTS and FRAP free radical scavenging activities were also measured. Total flavonoids and total phenolic contents were assayed and the antibacterial effect was tested against four species of bacteria; two Gram-positive (Staphylococcus aureus and Streptococcus agalactiae) and two Gram-negative (Escherichia coli and Klebsilla pneumonia). The tests were carried out using the disc diffusion, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods. Moreover, the acute toxicity was evaluated in vivo on the ethanol extract of MM to establish its safety when administered orally. In our results, both extracts of MM showed abilities to scavenge DPPH and ABTS free radicals, IC(50) values: (11.599 ± 0.84, 10.573 ± 0.58 µmol/L) and (62.657 ± 0.78, 63.939 ± 0.48 µmol/L) for ethanol and aqueous extracts respectively. Indeed the ethanol extract evidenced high phenolic content (384.33 ± 0.005 mg/g), flavonoids contents (85.8 ± 0.009 mg/g) and ferric reducing antioxidant power (33,590 ± 0.038 mmol/g), with high activity against S. aureus and S. agalactiae (11 ± 0.3 and 12 ± 0.6 mm inhibition zones). Likewise, the percentage of peripheral blood mononuclear cells (PBMC) viability was increased in response to MM, IC(50) values (1.781 ± 1.2 and 6.545 ± 0.93 µg/mL) for ethanol and aqueous extracts, respectively. In addition, our results showed that the MM extract is safe even at a high dose of 5,000 mg/kg and has no oral toxicity. These findings suggest the excellent medicinal bioactivity of MM and explain the popularity of this plant in the folk medicine as a remedy for different illnesses.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects
  13. Fulltext Flavonoid analyses and antimicrobial activity of various parts of Phaleria macrocarpa (Scheff.) Boerl fruit
    Hendra R, Ahmad S, Sukari A, Shukor MY, Oskoueian E
    Int J Mol Sci, 2011;12(6):3422-31.
    PMID: 21747685 DOI: 10.3390/ijms12063422
    Phaleria macrocarpa (Scheff.) Boerl (Thymelaceae) is commonly known as 'Crown of God', 'Mahkota Dewa', and 'Pau'. It originates from Papua Island, Indonesia and it grows in tropical areas. Empirically, it is potent in treating the hypertensive, diabetic, cancer and diuretic patients. It has a long history of ethnopharmacological usage, and the lack of information about its biological activities led us to investigate the possible biological activities by characterisation of flavonoids and antimicrobial activity of various part of P. macrocarpa against pathogenic bacteria and fungi. The results showed that kaempferol, myricetin, naringin, and rutin were the major flavonoids present in the pericarp while naringin and quercetin were found in the mesocarp and seed. Furthermore, the antibacterial activity of different parts of P. macrocarpa fruit showed a weak ability to moderate antibacterial activity against pathogenic tested bacteria (inhibition range: 0.93-2.17 cm) at concentration of 0.3 mg/disc. The anti fungi activity was only found in seed extract against Aspergillus niger (1.87 cm) at concentration of 0.3 mg/well. From the results obtained, P. macrocarpa fruit could be considered as a natural antimicrobial source due to the presence of flavonoid compounds.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects
  14. Synthesis and antimicrobial properties of some new thiazolyl coumarin derivatives
    Arshad A, Osman H, Bagley MC, Lam CK, Mohamad S, Zahariluddin AS
    Eur J Med Chem, 2011 Sep;46(9):3788-94.
    PMID: 21712145 DOI: 10.1016/j.ejmech.2011.05.044
    Two novel series of hydrazinyl thiazolyl coumarin derivatives have been synthesized and fully characterized by IR, (1)H NMR, (13)C NMR, elemental analysis and mass spectral data. The structures of some compounds were further confirmed by X-ray crystallography. All of these derivatives, 10a-d and 15a-h, were screened in vitro for antimicrobial activity against various bacteria species including Mycobacterium tuberculosis and Candida albicans. The compounds 10c, 10d and 15e exhibited very good activities against all of the tested microbial strains.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects
  15. A multicentre surveillance study on the characteristics, bacterial aetiologies and in vitro antibiotic susceptibilities in patients with acute exacerbations of chronic bronchitis
    Hui DS, Ip M, Ling T, Chang SC, Liao CH, Yoo CG, et al.
    Respirology, 2011 Apr;16(3):532-9.
    PMID: 21299688 DOI: 10.1111/j.1440-1843.2011.01943.x
    Antimicrobial resistance is a global problem and the prevalence is high in many Asian countries.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects
  16. Fulltext Antimicrobial properties of erythromycin and colistin impregnated bone cement. An in vitro analysis
    Ruzaimi MY, Shahril Y, Masbah O, Salasawati H
    Med J Malaysia, 2006 Feb;61 Suppl A:21-6.
    PMID: 17042224
    Deep surgical site infection is a devastating consequence of total joint arthroplasty. The use of antibiotic impregnated bone cement is a well-accepted adjunct for treatment of established infection and prevention of deep orthopaedic infection. It allows local delivery of the antibiotic at the cement-bone interface and sustained release of antibiotic provides adequate antibiotic coverage after the wound closure. Preclinical testing, randomised and clinical trials indicate that the use of antibiotic-impregnated bone cement is a potentially effective strategy in reducing the risk of deep surgical site infection following total joint arthroplasty. The purpose of this study was to assess antibacterial activity of erythromycin and colistin impregnated bone cement against strains of organisms' representative of orthopaedic infections including Gram-positive and Gram-negative aerobic organisms: Staphylococcus aureus, coagulase-negative Staphylococci, Enterococcus sp., Proteus sp., Klebsiella sp., Pseudomonas sp., and Escherichia coli. Pre-blended Simplex P bone cement with the addition of erythromycin and colistin (Howemedica Inc) was mixed thoroughly with 20ml liquid under sterile conditions to produce uniform cylindrical discs with a diameter of 14mm and thickness of 2mm. 24-48 hour agar cultures of Staphylococcus aureus, coagulase-negative Staphylococci, Enterococcus sp.,Proteus sp., Klebsiella sp.,Pseudomonas sp., and Escherichia coli were used for the agar diffusion tests. The agar plates were streaked for confluent growth followed by application of erythromycin and colistin impregnated bone cement disc to each agar plate. The plates were incubated at 30 degrees C and examined at 24, 48, 72 hours, and four and five days after the preparation of the impregnated cement. The susceptibility of Staphylococcus aureus to the control discs was most clearly demonstrated showing a distinct zone of inhibition. The zone observed around coagulase-negative Staphylococci, Klebsiella sp., Pseudomonas sp., and Escherichia coli were also significant. However, there was no zone of inhibition or signs of antibacterial activity at the cemented surface were detected around discs with Enterococcus sp. and Proteus sp. The results showed that Simplex P bone cement with the addition of erythromycin and colistin was effective against most of the broad spectrum organisms encountered during total joint arthroplasty. The activity of Simplex P bone cement impregnated with erythromycin and colistin is mainly during the first 72 hours.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects*
  17. Resistoflavine, cytotoxic compound from a marine actinomycete, Streptomyces chibaensis AUBN1/7
    Gorajana A, Venkatesan M, Vinjamuri S, Kurada BV, Peela S, Jangam P, et al.
    Microbiol Res, 2007;162(4):322-7.
    PMID: 16580188
    In our systematic screening programme for marine actinomycetes, a bioactive Streptomycete was isolated from marine sediment samples of Bay of Bengal, India. The taxonomic studies indicated that the isolate belongs to Streptomyces chibaensis and it was designated as S. chibaensis AUBN1/7. The isolate yielded a cytotoxic compound. It was obtained by solvent extraction followed by the chromatographic purification. Based on the spectral data of the pure compound, it was identified as quinone-related antibiotic, resistoflavine (1). It showed a potent cytotoxic activity against cell lines viz. HMO2 (Gastric adenocarcinoma) and HePG2 (Hepatic carcinoma) in vitro and also exhibited weak antibacterial activities against Gram-positive and Gram-negative bacteria.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects
  18. Biosynthesis and structural characterization of Ag nanoparticles from white rot fungi
    Chan YS, Mat Don M
    Mater Sci Eng C Mater Biol Appl, 2013 Jan 1;33(1):282-8.
    PMID: 25428073 DOI: 10.1016/j.msec.2012.08.041
    Five species of white rot fungi were screened for their capability to synthesize Ag nanoparticles (AgNPs). Three modes of AgNP bioreduction were developed. Pycnoporus sanguineus is found as a potential candidate for the synthesis of AgNPs with a yield at 98.9%. The synthesized AgNPs were characterized using UV-vis spectroscopy, DLS, FTIR, TEM, and SEM. Results showed that AgNP absorption band was located at a peak of 420 nm. Both the SEM and TEM confirmed that the formation of AgNPs were mainly spherical with average diameters of 52.8-103.3 nm. The signals of silver atoms' presence in the mycelium were observed by SEM-EDS spectrum.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects
  19. Screening antimicrobial activity of various extracts of Urtica dioica
    Modarresi-Chahardehi A, Ibrahim D, Fariza-Sulaiman S, Mousavi L
    Rev. Biol. Trop., 2012 Dec;60(4):1567-76.
    PMID: 23342511
    Urtica dioica or stinging nettle is traditionally used as an herbal medicine in Western Asia. The current study represents the investigation of antimicrobial activity of U. dioica from nine crude extracts that were prepared using different organic solvents, obtained from two extraction methods: the Soxhlet extractor (Method I), which included the use of four solvents with ethyl acetate and hexane, or the sequential partitions (Method II) with a five solvent system (butanol). The antibacterial and antifungal activities of crude extracts were tested against 28 bacteria, three yeast strains and seven fungal isolates by the disc diffusion and broth dilution methods. Amoxicillin was used as positive control for bacteria strains, vancomycin for Streptococcus sp., miconazole nitrate (30 microg/mL) as positive control for fungi and yeast, and pure methanol (v/v) as negative control. The disc diffusion assay was used to determine the sensitivity of the samples, whilst the broth dilution method was used for the determination of the minimal inhibition concentration (MIC). The ethyl acetate and hexane extract from extraction method I (EA I and HE I) exhibited highest inhibition against some pathogenic bacteria such as Bacillus cereus, MRSA and Vibrio parahaemolyticus. A selection of extracts that showed some activity was further tested for the MIC and minimal bactericidal concentrations (MBC). MIC values of Bacillus subtilis and Methicillin-resistant Staphylococcus aureus (MRSA) using butanol extract of extraction method II (BE II) were 8.33 and 16.33mg/mL, respectively; while the MIC value using ethyl acetate extract of extraction method II (EAE II) for Vibrio parahaemolyticus was 0.13mg/mL. Our study showed that 47.06% of extracts inhibited Gram-negative (8 out of 17), and 63.63% of extracts also inhibited Gram-positive bacteria (7 out of 11); besides, statistically the frequency of antimicrobial activity was 13.45% (35 out of 342) which in this among 21.71% belongs to antimicrobial activity extracts from extraction method I (33 out of 152 of crude extracts) and 6.82% from extraction method II (13 out of 190 of crude extracts). However, crude extracts from method I exhibited better antimicrobial activity against the Gram-positive bacteria than the Gram-negative bacteria. The positive results on medicinal plants screening for antibacterial activity constitutes primary information for further phytochemical and pharmacological studies. Therefore, the extracts could be suitable as antimicrobial agents in pharmaceutical and food industry.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects*
  20. Isolation and identification of antibacterial and cytotoxic compounds from the leaves of Muntingia calabura L
    Sufian AS, Ramasamy K, Ahmat N, Zakaria ZA, Yusof MI
    J Ethnopharmacol, 2013 Mar 7;146(1):198-204.
    PMID: 23276785 DOI: 10.1016/j.jep.2012.12.032
    Muntingia calabura (Elaeocarpaceae) is one of the most common roadside trees in Malaysia. Its leaves, barks, flowers and roots have been used as a folk remedy for the treatment of fever, incipient cold, liver disease, as well as an antiseptic agent in Southeast Asia. The aim of this study is to isolate and identify the antibacterial and cytotoxic compounds from the leaves of Muntingia calabura L.
    Matched MeSH terms: Gram-Negative Bacteria/drug effects
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