Iridium(III) Complexes Containing 1,10-Phenanthroline and Derivatives: Synthetic, Stereochemical, and Structural Studies, and their Antimicrobial Activity

2013 ◽  
Vol 66 (9) ◽  
pp. 1065 ◽  
Author(s):  
Mallesh Pandrala ◽  
Fangfei Li ◽  
Lynne Wallace ◽  
Peter J. Steel ◽  
Barry Moore II ◽  
...  

A convenient synthetic strategy is reported for the series of complexes [Ir(pp)3]3+ (where pp = phen, Me2phen and Me4phen) through the intermediacy of the appropriate [Ir(pp)2(CF3SO3)2]+ species. In the case of [Ir(phen)3]3+, the cation was resolved into its enantiomeric forms, for which the absolute configurations were determined by X-ray diffraction. The availability for the first time of the CD spectra allowed comparison with computed CD spectra. Measurement of the antimicrobial activity of the [Ir(pp)3]3+ species {and the [Ir(pp)2X2]+ (X = Cl–, CF3SO3–) precursors involved in their synthesis}, as well as cell uptake studies with the four bacterial strains S. aureus, methicillin-resistant S. aureus (MRSA), E. coli, and P. aeruginosa, indicated that they showed little activity compared with their Ru(ii) analogues. The results suggest that it is unfavourable for an individual metal centre with a 3+ charge to pass across the bacterial cell membrane.

Author(s):  
Singh Gurvinder ◽  
Singh Prabhsimran ◽  
Dhawan R. K.

In order to develop new antimicrobial agents, a series of 3-formyl indole based Schiff bases were synthesized by reacting 3-formyl indole(indole-3-carboxaldehyde) with substituted aniline taking ethanol as solvent. The reaction was carried in the presence of small amount of p-toluene sulphonic acid as catalyst.All the synthesized compounds were characterized by IR, 1H-NMR spectral analysis. All the synthesized compounds were evaluated for antimicrobial activity against two gram positive bacterial strains (B. subtilisand S. aureus) and two gram negative bacterial strains (P. aeruginosaand E. coli) and one fungal strain (C. albicans). All the synthesized compounds were found to have moderate to good antimicrobial activity. The  standard drug amoxicillin, fluconazole were used for antimicrobial activity. Among the synthesized compounds, the maximum antimicrobial activity was shown by compounds GS04, GS07, GS08 and GS10.


2014 ◽  
Vol 2 (4) ◽  
pp. 521-524
Author(s):  
RP Praveen ◽  
Ashalantha Nair

The aim of the present study was to compare the antimicrobial efficacy of methanolic extract of root, callus and fruit of Myxopyrum smilacifolium Blume. Antimicrobial activity was tested using agar well diffusion with four bacterial strains viz: Escherechia coli, Enterococcus faecalis, Bacillus subtilis and Staphylococcus aureus of which E. coli alone was gram negative. The fungal strain employed was Candida albicans. Root extracts shown to be effective only against B. subtilis. Fruit extracts showed the maximum antimicrobial activity against all the microbial species considered for the current study except against S. aureus. Highlight of the present study was the antimicrobial activity of callus extracts. DOI: http://dx.doi.org/10.3126/ijasbt.v2i4.11362  Int J Appl Sci Biotechnol, Vol. 2(4): 521-524 


Author(s):  
M. V. Sycheva ◽  
A. S. Vasilchenko ◽  
E. A. Rogozhin ◽  
T. M. Pashkova ◽  
L. P. Popova ◽  
...  

Aim. Isolation and study ofbiological activity of antimicrobial peptides from chickens thrombocytes. Materials and methods. Peptides from chickens thrombocytes, obtained by reverse-phase high-performance liquid chromatography method with stepped and linear gradients of concentration increase of the organic solvent were used in the study. Their antimicrobial activity was determined by microtitration method in broth; mechanism of biological effect - by using fluorescent spectroscopy method with DNA-tropic dyes. Results. Individual fractions of peptides were isolated from chickens thrombocytes, that possess antimicrobial activity against Staphylococcus aureus P209 and Escherichia coli K12. A disruption of integrity of barrier structures of microorganisms under the effect of thrombocyte antimicrobial peptides and predominance of cells with damaged membrane in the population of E. coli was established. Conclusion. The data obtained on antimicrobial activity and mechanism of bactericidal effect of the peptide fractions from chickens thrombocytes isolated for the first time expand the understanding of functional properties of chickens thrombocytes and open a perspective for their further study with the aim of use as antimicrobial means.


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.


2021 ◽  
Vol 14 (9) ◽  
pp. 913
Author(s):  
Maria Antónia Nunes ◽  
Josman Dantas Palmeira ◽  
Diana Melo ◽  
Susana Machado ◽  
Joana Correia Lobo ◽  
...  

Olive pomace, an olive oil processing byproduct, can be upcycled and meet the current demand for natural and sustainable food ingredients. In this work, a patented process was used to obtain a functional ingredient from different olive pomaces. The nutritional, chemical and antioxidant profiles, as well as the antimicrobial activity against S. aureus, E. coli and C. albicans, were investigated for the first time. The amount of phenolics ranged between 3.1 and 3.8 g gallic acid eq./100 g in all samples and flavonoids between 2.0 and 3.2 g catechin eq/100 g. No significant differences were found regarding the antioxidant activity. The total fat varied between 5 and 11%, α-tocopherol being the major vitamer and oleic acid the main fatty acid. The protein and ash contents were 1–4% and 10–17%, respectively. The functional ingredient with a higher hydroxytyrosol content (220 mg/100 g) also presented the best minimal inhibitory concentration against the tested bacteria. No activity against C. albicans was verified. This new functional ingredient presents the potential to be used as a natural preservative or as a nutritional profile enhancer. Moreover, it can be an advantageous ingredient in food products, since it comprises specific lipid and hydrophilic bioactive compounds usually not present in other plant extracts.


F1000Research ◽  
2018 ◽  
Vol 7 ◽  
pp. 1200
Author(s):  
Cecilia Barba Guevara ◽  
Luis Montaluisa ◽  
María Elena Maldonado Rodriguez

Background: This research was carried out in order to study the antimicrobial effectiveness of crude latex of two varieties of "Sangre de Drago": Croton lechleri Muller Arg. and Croton urucurana Baill and compare that effectiveness to the antimicrobial activity of the alcoholic extracts of its leaves and bark.  Methods: The activity of the alcoholic extracts and latex were evaluated against bacterial strains of Staphylococcus epidermidis, Bacillus subtilis and Escherichia coli. The extraction of the alcoholic extracts (20% Tincture) of the leaves, bark and latex from the two Croton species was carried out by maceration using 70% alcohol as a menstruum, at room temperature, for 2 to 7 days, with shaking at least twice a day.  A 20% tincture was obtained, from which the physical and chemical parameters were determined as indicated by the Ecuadorian Quality Control Standard for natural medicinal products. Results: It was found that both the alcoholic extracts of the plant material and the crude latex indicate antimicrobial activity for S. epidermidis, moderate antimicrobial activity for B. subtilis and no antimicrobial activity for E. coli. The moderate antimicrobial activity against B. subtilis, at doses of 125 p.p.m., is in line with the findings of previous studies by other authors.  Conclusions: he antimicrobial activity of the latex of the two species against S. epidermidis is not registered in literature and, the negative antimicrobial activity for E. coli does not agree with what has been reported by previous studies.


2020 ◽  
Vol 09 ◽  
Author(s):  
Yamuna Saravanan ◽  
Bala Subramaniam Devaraj ◽  
Nithesh Kumar Velusamy ◽  
Pooja Shree Soundirarajan ◽  
Kumaravel Kandaswamy

Background:: Phytochemicals such as tannins, alkaloids, flavonoids, and peptides been found to have antimicrobial activity against a variety of bacterial strains. Objective:: However, optimal extraction procedures for these phytochemicals and their efficacy evaluation against certain pathogenic bacterial strains remain unclear. Method:: Therefore, in this study phytochemicals from Leucas aspera (L. aspera) and Dahlia pinnata (D. pinnata) were extracted by hot and cold extraction methods using water and methanol as solvents. In addition, antimicrobial activity of L. aspera and D. pinnata extracts against bacterial strains such as the gram-negative Escherichia coli (E. coli) and the gram-positive Enterococcus faecalis (E. faecalis) were performed by Minimal Inhibitory Concentration (MIC) and CFU quantification assays. Results:: The majority of the phytochemicals such as protein, carbohydrate, tannins, flavonoids, phenols, and saponins were present in our extracts but steroids were absent in the extract. Protein, tannins, flavonoids, phenols, and saponins were present in both L. aspera and D. pinnata. The yield of proteins was high (1.990 ± 0.091 mg/ml) in methanol extracts of L. aspera and low (0.199 mg/ml) in aqueous extracts. However, the yield of tannins was high (1.713 ± 0.079 mg/ml) in methanol extracts of D. pinnata and low (0.528 ± 0.136 mg/ml) aqueous extracts. The MIC of D. pinnata extracts were found to be 200 mg/ml for both E. coli and E. faecalis. However the L. aspera extracts had a MIC of 100 mg/ml and 200 mg/ml on E. coli and E. faecalis, respectively. Conclusion:: This article demonstrated the potential use of phytochemicals as novel antimicrobial compounds against bacterial infections.


2016 ◽  
Vol 5 (09) ◽  
pp. 4885 ◽  
Author(s):  
Khushbu Pandey ◽  
Mahendra Singh* ◽  
Bharat Pandey ◽  
Anshulika Upadhyaya ◽  
Kamal K. Pande

The present study was carried out for phytochemical screening of principle bioactive compounds and antimicrobial activity in Elaeocarpus ganitrus Roxb., Phytochemical analysis revealed the presence of saponin, terpenoid, steroid, saponin, flavonoid, tannin and alkaloid. The petroleum, ether, chloroform, methanol, acetone and aqueous extracts were subjected to antimicrobial activity against bacterial strains Staphylococcus aureus, Pseudomonas, E. coli and Bacillus subtilis against anti-fungal strains A.awamori, A.fumigatus, Rhizopus oryzae, Trichoderma viridae and C.oryzae. The antibacterial and antifungal activity was evaluated by disc-diffusion method.


2012 ◽  
Vol 65 (4) ◽  
pp. 343 ◽  
Author(s):  
Mei Zhang ◽  
Dong-Mei Xian ◽  
Hai-Hua Li ◽  
Ji-Cai Zhang ◽  
Zhong-Lu You

A series of new halo-substituted aroylhydrazones have been prepared and structurally characterized by elemental analysis, 1H NMR, 13C NMR, and IR spectra, and single crystal X-ray diffraction. The compounds were evaluated for their antibacterial (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, and Pseudomonas fluorescence) and antifungal (Candida albicans and Aspergillus niger) activities by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method. Among the tested compounds, N′-(2-chloro-5-nitrobenzylidene)-2-fluorobenzohydrazide showed the most effective antimicrobial activity with minimum inhibitory concentration values of 0.82, 2.5, 1.7, 15.2, and 37.5 μg mL–1 against B. subtilis, S. aureus, E. coli, P. fluorescence, and C. albicans, respectively. The biological assay indicated that the presence of the electron-withdrawing groups in the aroylhydrazones improved their antimicrobial activities.


2018 ◽  
Vol 15 (1) ◽  
pp. 21-30
Author(s):  
Deboleena Dhara ◽  
Dhanya Sunil ◽  
Pooja R. Kamath ◽  
K. Ananda ◽  
S. Shrilakshmi ◽  
...  

Introduction: The escalating threat due to dwindling effect of antibiotics and challenge of tackling rising drug-resistant infections has gathered high focus in current medicinal research. Methods: In an attempt to find new molecules that can defeat microbial resistance, two new series of 2-[2-substituted ethenyl]-5-(substituted methoxy)-1,3,4-oxadiazole derivatives were synthesized. Various aromatic hydrazides were allowed to undergo cyclization to substituted oxadiazole-2- amines in the presence of cyanogen bromide and further condensed with different heterocyclic aldehydes to give new oxadiazole derivatives. The synthesized molecules were fully characterized by various spectral techniques and tested for antimicrobial activity. Results: Almost all the newly synthesized compounds especially (5g-5l) displayed remarkable growth inhibition against three bacterial strains: M. smegmatis, S. aureus, E. coli and fungi C. albicans. The antimicrobial activity was further confirmed by MIC assay against the same microorganisms. Oxadiazole 5g displayed promising activity with a MIC value of 0.025 mM for two bacteria and fungi, whereas MIC of this compound for E. coli was 0.1 mM. Other active compounds (5h-5l) also exhibited good MIC ranging between 0.313 to 5.0 mM against the selected microorganisms. Docking simulations were generated to explore the potential binding approaches of ligand 5g at the D-alanine:d-alanine ligase (Ddl) protein of E. coli and S. aureus. Conclusion: Molecule 5g was active even at a lower concentration and could probably act as a prospective lead molecule for targeting the drug resistant microorganisms.


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