scholarly journals C-3 Substituted Lawsonemonoximates of Holmium(III): Synthesis, Characterization, and Antimicrobial Activity

2000 ◽  
Vol 7 (3) ◽  
pp. 147-150 ◽  
Author(s):  
S. B. Jagtap ◽  
S. G. Joshi ◽  
G. M. Litake ◽  
V. S. Ghole ◽  
B. A. Kulkarni

A series of five new metal complexes of Ho(III) with C-3 substituted derivatives of lawsonemonexime (2-hydroxy-1,4-naphthalenediene-1-oxime) were synthesized. The compounds were characterized by melting point, elemental analysis, IR spectroscopy and magnetic susceptibility. The antimicrobial activity of the compounds were determined by disk diffusion method and broth micro-dilution techniques using Mueller Hinton medium against the following organisms: S. aureus ATCC 6538P, Klebsiella pneumoniae, NCTC 418, Pseudomonas aeruginosa ATCC 27833, Salmonella typhimurium ATCC 23564, E. coli U 1777, E. coli HB101, Proteus morganii NCIM 2860, Providencia stuartii NCIM 2799 and Acinetobacter baumannii U 24. The chelates of Ho(III) with lawsonemonoxime and Ho(III) with 3-bromolawsonemonoxime showed a variable antimicrobial activity against all organisms tested except Pseudomonas and Klebsiella spp. S. aureus was found more sensitive to all ligands and chelates tested; but the MIC values of chelates were considerably less; thus having more antimicrobial effect.

2020 ◽  
Vol 2020 ◽  
pp. 1-7 ◽  
Author(s):  
Pavithra L. Jayatilake ◽  
Helani Munasinghe

Endophytic and rhizosphere fungi are understood to be aiding the host plant to overcome a range of biotic and abiotic stresses (nutrition depletion, droughts, etc.) hence, they remain to be reservoirs of plethora of natural products with immense use. Consequently, this investigation of endophytic and rhizosphere fungi isolated from Mikania cordata (a perennial vine that is well established in Sri Lanka) for their antimicrobial properties was performed with the aim of future derivation of potential beneficial pharmaceutical products. Leaves, twigs, and roots of M. cordata were utilized to isolate a total of 9 endophytic fungi out of which the highest amount (44%) accounted was from the twigs. A sample of the immediate layer of soil adhering to the root of M. cordata was utilized to isolate 15 rhizosphere fungi. Fusarium equiseti and Phoma medicaginis were endophytes that were identified based on colony and molecular characteristics. The broad spectrum of antimicrobial activity depicted by F. equiseti (MK517551) was found to be significantly greater (p≤0.05, inhibitory against Bacillus cereus ATCC 11778, Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 25853) than P. medicaginis (MK517550) (inhibitory against Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 25853) as assessed using the Kirby-Bauer disk diffusion method. Trichoderma virens and Trichoderma asperellum were rhizospere fungi that exhibited remarkable antimicrobial properties against the test pathogens chosen for the study. T. asperellum indicated significantly greater bioactivity against all four bacterial pathogens and Candida albicans ATCC 10231 under study. The ranges of minimum inhibitory concentrations (MICs) of the fungi depicting antimicrobial properties were determined. The results obtained suggest that F. equiseti, P. medicaginis, T. asperellum, and T. virens of M. cordata harness bioprospective values as natural drug candidates. This is the first report on isolation and evaluation of the antimicrobial properties of endophytic and rhizosphere fungi of Mikania cordata.


1999 ◽  
Vol 6 (3) ◽  
pp. 163-167 ◽  
Author(s):  
Bahri Ülküseven ◽  
Aydin Tavman ◽  
Gülten Ötük

The metal complexes of nine 2-substituted-1H-benzimidazoles (I-IX) with Ni(II), Pd(II), Cu(II), Ag(I), Zn(II) salts were synthesized. The compounds were characterized by melting point, analytical data, IR spectroscopy and magnetic susceptibility. The antimicrobial activity of the compounds was determined by the disk diffusion method in Mueller-Hinton Agar on Staphylococcus aureusATCC 6538, Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 8739, Klebsiella pneumoniae ATCC 4352, Pseudomonas aeruginosa ATCC 1539, Salmonella typhi, Shigella flexneri, Proteus mirabilis, Candida albicans ATCC 10231. Cu(II)and Ag(I)complexes of II, III and IV showed considerable activity against S. aureus, S. epidermidis, Ps. aeruginosa, S. typhi, Sh. flexneri and C. albicans microorganisms, the ligands themselves having no effect.


2017 ◽  
Vol 119 (10) ◽  
pp. 2277-2286 ◽  
Author(s):  
Sireerat Laodheerasiri ◽  
Nirasha Horana Pathirage

Purpose The purpose of this paper is to determine the antimicrobial compounds extracted from various types of soybean materials; raw soybean, soybean flour and roasted soybean. Bacteria growth inhibition was tested in E.coli and S. aureus by disk diffusion method. Efficiency of antimicrobial activities were compared among the extracted solution. Design/methodology/approach Soybean (Glycine max) isoflavones contain the ability to inhibit the growth of many strains of microorganisms. The solid-liquid extraction, ethanol-hexane extraction, was modified to isolate the inhibitory compounds from the three different types of soybean materials. All crude extracts at various concentrations performed under different extracted solutions (75, 50, 25, 12.5, 6.25 and 3.125 percent) were tested with E. coli. and S. aureus to determine the antimicrobial activities and the minimum inhibition concentration (MIC). Disk diffusion method was chosen to study the antimicrobial activity of isoflavones. Findings Soybean flour extract inhibited the growth of E. coli and S. aureus more effective than roasted soybean and raw soybean, respectively. The MIC of inhibitory compounds extracted from soybean flour was 6.25 percent (0.031 mg/ml), roasted soybean was 25 percent (0.125 mg/ml) and raw soybean was 50 percent (0.250 mg/ml). Crude extracts of soybean flour and roasted soybean showed better results than raw soybean. All the three of extracted soybeans inhibited the growth of E. coli better than S. aureus. Originality/value Ethanol-hexane extraction was successfully used to isolate the antimicrobial compounds from raw soybean, soybean flour and roasted soybean. Comparison of antimicrobial activity showed that soybean flour contained the highest inhibition activity.


2021 ◽  
Vol 14 (4) ◽  
pp. 1730-1736
Author(s):  
Kalpana. P. R

Chitosan, a cationic biopolymer is a major derivative of chitin. It is biocompatible, non-toxic and environ-friendly material and has broad spectrum antimicrobial activity. However, it is less effective in neutral or basic conditions due to its solubility only in acidic medium. Therefore, chemical modification with suitable groups is necessary to enhance the potency of chitosan. The present study was mainly conducted to explore the effect of structural modifications on antimicrobial potential of chitosan. N-Methyl, N-Ethyl and N-Propyl pyrrole were reacted with N-chloroacyl-6-O-triphenylmethylchitosan prepared by stepwise modification of chitosan to form N-Methyl, N-Ethyl and N-Propyl pyrrole derivatives of chitosan. Structural characterization of these pyrrole derivatives was done by IR, NMR, XRD, DSC and Elemental Analysis. The gram-negative bacterium Escherichia coli, gram-positive bacterium Staphylococcus aureus were selected for antibacterial activity and the fungus C. albicans was selected for antifungal activity by agar diffusion method and MIC method. Antimicrobial activity of the N-Methyl, N-Ethyl and N-Propyl pyrrole derivatives on E. coli, S. aureus and C. albicans showed an inhibitory effect on all the organisms. The potency of inhibition was found to be varied with the substitutions. The maximum activity was shown by N-pyrrolylpropylchitosan against E. coli (zone of inhibition 1.2±0.05cm, MIC 0.15±0.03mg/ml), S. aureus (zone of inhibition 1.4±0.03cm, MIC 0.15±0.01mg/ml), C. albicans (zone of inhibition 0.8±0.03cm, MIC 0.2±0.03mg/ml). The study also confirmed that all the three derivatives exhibited higher inhibition than that of chitosan against E. coli (zone of inhibition 0.7±0.03cm, MIC 0.09±0.02mg/ml), S. aureus (zone of inhibition 0.8±0.03cm, MIC 0.09±0.02mg/ml), C. albicans (zone of inhibition 0.6±0.03cm, MIC 0.09±0.03mg/ml). Results demonstrated that these three N-alkylpyrrole chitosan derivatives exhibited improved potency and hence can have the more applicability as antimicrobials.


2020 ◽  
Vol 4 (1) ◽  
pp. 49
Author(s):  
Gracielle Oliveira Sabbag Cunha ◽  
Ana Paula Terezan ◽  
Andreia Pereira Matos ◽  
Marcela Carmen De Melo Burger ◽  
Paulo Cezar Vieira ◽  
...  

This study evaluated the antimicrobial activity of isolated compounds and semisynthetic derivatives from Miconia ferruginata (Melastomataceae) against five microorganisms: Staphylococcus aureus (ATCC 25923), Escherichia coli (ATCC 25922), Bacillus subtilis (ATCC 6623), Pseudomonas aeruginosa (ATCC 15442), and Candida albicans (ATCC 10231). The isomeric mixture of ursolic and oleanolic acids was active against S. aureus (MIC = 250 μg mL-1) and against E. coli, B. subtilis, and P. aeruginosa (MIC = 500 μg mL-1). The flavone 5,6,7-trihydroxy-4’-methoxyflavone and the methyl esters, semisynthetic derivatives of a mixture of ursolic and oleanolic acids, showed no activity against the tested microorganisms. These results suggest that the carboxyl group present in the triterpenes may contribute to antimicrobial activity.


Author(s):  
SHIBU GEORGE ◽  
MEVLIN JOY

Objective: The objective of this study was to evaluate the antimicrobial activity of methanolic extract of Ludwigia parviflora L. using standard bacterial strains and compare its activity with that of standard antibiotics. Methods: The antibacterial activity and antibiotic susceptibility tests were done by disk diffusion method using MTCC bacterial strains. Results: The study revealed that the methanolic extract of the whole plant of L. parviflora L. was effective to inhibit the growth of Staphylococcus aureus, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Escherichia coli. Among the tested strains, S. aureus, P. aeruginosa, K. pneumoniae, and E. coli were more susceptible to the methanolic extract of L. parviflora than the commonly using antibiotic tetracycline 30 mcg. The activity of methanolic extract was also higher than the activity of gentamicin 10 mcg against the P. aeruginosa. Conclusion: The study concluded that the crude methanolic extract of the whole plant of L. parviflora L. is a good source for antibacterial agent against S. aureus, P. aeruginosa, K. pneumoniae, and E. coli. Hence, this plant can be used as a natural alternative to the common antibiotics such as gentamicin and tetracycline against common bacterial infections after validating its pharmacological and toxicological activities.


2015 ◽  
Vol 1 (1) ◽  
Author(s):  
Caroline Suryadi ◽  
Djaja Rusmana ◽  
Endang Evacuasiany

Escherichia coli is the most common bacteria that cause diarrhea. Based on Kurniawati’s research, ethanol extract of tamarind leaves has an antimicrobial effect to Escherichia coli. This study aims to determine the antimicrobial effect using disk diffusion method, the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of tamarind leaves infusion against Escherichia coli. This research was done using a real laboratory experimental design with tamarind leaves infusion and Escherichia coli microbes as the research objects. Zones of inhibition were observed using disk diffusion method by putting the tamarind leaves infusion disks on Mueller-Hinton agars with Ampicillin antibiotic for comparison, followed by observing the MIC using macro broth dilution method  and MBC. The result of disk diffusion showed that tamarind leaves infusion had no zone of inhibition, whereas the mean value of the zones of inhibition of ampicillin is 17.2 mm. The MIC of tamarind leaves infusion is 62.5 mg/mL. Average growth of bacteria  for the MBC of tamarind leaves infusion at 125 mg/mL and 62.5 mg/mL concentration are 13 CFU/mL and >300 CFU/mL. It can be concluded that tamarind leaves infusion has antimicrobial activity effect against E.coli and that effect is bacteriostatic. Keywords: Tamarindus indica Linn, Escherichia coli, MIC, MBC


2015 ◽  
Vol 43 (2) ◽  
pp. 327-334 ◽  
Author(s):  
Mihaela NICULAE ◽  
Laura STAN ◽  
Emoke PALL ◽  
Anamaria Ioana PAȘTIU ◽  
Iulia Maria BALACI ◽  
...  

The study was aimed to characterize the chemical composition and the antimicrobial activity of Romanian propolis ethanolic extracts (EEP) against antibiotic-sensitive and antibiotic-resistant E. coli strains isolated from bovine mastitis. The preliminary antimicrobial screening was performed by a disk diffusion method, followed by determination of minimum inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) based on broth microdilution assay; further, the synergistic action of propolis with antimicrobial drugs was assessed by a disk diffusion method on agar containing subinhibitory concentrations of propolis. For the chemical characterisation of EEP, the flavonoids (flavones/flavonols, flavanones/dihydroflavonols) and total phenolics were evaluated by spectrophotometric methods. The phenolic compounds of these extracts were also determined using HPLC. The results indicated for Romanian propolis ethanolic extracts the typical poplar composition profile with flavonoids and phenolic acids as main biological active compounds, with chromatographic analysis data confirmed also spectrophotometrically. In addition, positively correlated with the chemical composition, a strong antimicrobial efficacy was exhibited towards E. coli strains, along with interesting synergistic interaction with antibiotics that can be further investigated to obtain propolis-based formulation with antibacterial properties. Subsequent in vitro and in vivo studies evaluating the safety and efficacy are intended to consider propolis in veterinary therapeutic protocols.


Author(s):  
Ahmad Jafari ◽  
Ramin Mazaheri Nezhad Fard ◽  
Sima Shahabi ◽  
Farid Abbasi ◽  
Golshid Javdani Shahedin ◽  
...  

Background and Objectives: Silver nanoparticles (Ag-NPs) are potent antimicrobial agents, which have recently been used in dentistry. The aim of the current study was to optimize antimicrobial activity of Ag-NPs used in preparing irre- versible hydrocolloid impressions against three microorganisms of Escherichia coli, Streptococcus mutans and Candida albicans. Materials and Methods: After assessing antimicrobial activity of the compound using disk diffusion method, three parame- ters of concentration of Ag-NPs (250-1000 ppm), ratio of hydrocolloid impression material powder to water (0.30-0.50) and time of mixing (20.0-60.0 s), affecting antimicrobial activity of irreversible hydrocolloid impression materials against the three microorganisms, were optimized. This combined process was successfully modeled and optimized using Box-Behnken design with response surface methodology (RSM). Decreases in colony number of E. coli, S. mutans and C. albicans were proposed as responses. Results: Qualitative antimicrobial assessments respectively showed average zone of inhibition (ZOI) of 3.7 mm for E. coli, 3.5 mm for S. mutans and 4 mm for C. albicans. For all responses, when the mixing duration and powder-to-water ratio increased, the circumstances (mixing duration of 59.38 s, powder-to-water ratio of 0.4 and Ag-NP concentration of 992 response) increased. Results showed that in optimum ppm, the proportion of decreases in colony numbers was maximum (89.03% for E. coli, 87.08% for S. mutans and 74.54% for C. albicans). Regression analysis illustrated a good fit of the ex- perimental data to the predicted model as high correlation coefficients validated that the predicted model was well fitted with data. Values of R2Adj with R2Pred were associated to the accuracy of this model in all responses. Conclusion: Disinfection efficiency dramatically increased with increasing of Ag-NP concentration, powder-to-water ratio and mixing time.


Author(s):  
V. V. Pantyo ◽  
M. M. Fizer ◽  
O. I. Fizer ◽  
G. M. Koval ◽  
E.M. Danko

Annotation. The development and rapid pace of the spread of resistance to antimicrobial agents predetermines the search for new methods of counteracting pathogenic and conditionally pathogenic microorganisms. In this context, studies of the antimicrobial activity of newly synthesized chemicals, which in the future can be considered as candidates for antiseptic and disinfectants, are relevant. The aim of the work was to determine the antimicrobial activity of new ionic associates based on the surface-active cetylpyridinium cation with respect to certain opportunistic microorganisms. The antimicrobial activity of four ionic associates based on the cetylpyridinium cation with respect to clinical isolates of E. coli, P. vulgaris, K. pneumonia, P. aeruginosa, S. aureus, as well as the collection test strains of S. aureus ATCC 25923, E. coli ATCC 29522 and P. aeruginosa ATCC 27853 was studied. Screening studies were performed by the disk diffusion method. With substances that showed an antimicrobial effect, quantitative studies were carried out by the method of serial macro-dilutions in a liquid nutrient media. Screening studies revealed the antibacterial activity of the substances against E. coli ATCC 25923, E. coli (clinical isolate), P. vulgaris and K. pneumonia. With these microorganisms quantitative studies were carried out with the determination of the minimum inhibitory and minimum bactericidal concentrations. The most pronounced antimicrobial activity for the investigated microflora was shown by tetraphenylborate and cetylpyridinium perchlorate. The MIC and MBC values of these substances ranged between 1.625–3.125 mmol / L and 3.125–12.5 mmol / L, respectively. The studied associates showed high antimicrobial activity against representatives of the Enterobacteriaceae family in in vitro studies. Promising is the further study of the effect of the counter-anion associates of cationic surfactants on the biofilm formation of conditionally pathogenic microorganisms.


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