Showing 3 results for Inhibitory
Mohsen Fatemi, Nasrin Mollania, Madjid Momeni-Moghaddam, Fatemeh Sadeghifar,
Volume 6, Issue 1 (5-2019)
Abstract
New properties of nano-materials have made nanotechnology the leading part of biology and medical sciences. Due to their various biomedical properties, iron-based magnetic nanoparticles (MNPs) have been highly considered by biological researchers. Nowadays, increasing resistance to antibiotics is a major problem in treating clinical infections. Finding new antibacterial agents is therefore essential for the treatment of resistant strains. In this study, the iron oxide MNPs were produced using culture-medium supernatant of a newly isolated bacterium to investigate the inhibitory effects of the NPs on strains with a major role in clinical infections. Biosynthesis of iron oxide MNPs were detected by UV-Vis spectroscopy and the average size of particles was estimated by dynamic light scattering technique. The anti-bacterial activity of these NPs against E. coli and S. aureus was investigated using methods for the calculation of bacterial sensitivity coefficient. In the presence of NPs, the highest sensitivity coefficient value was observed for E. coli in 1xMIC concentration. On the other hand, S. aureus showed the lowest value. The death rate of the two strains in contact with NPs followed the first order kinetic equation and the survival rate decreased with the increase of exposure time. The results of this study as well as the high functionality of iron oxide MNPs, make its application desirable in the prevention and treatment of clinical infections.
Asghar Mosleh Arany, Navid Nemati, Hengame Zandi, Mostafa Naderi,
Volume 6, Issue 4 (1-2020)
Abstract
The aim of this study was to evaluate the antibacterial activity of the water extracts of three species of Salvia (S. perspolitana, S. palaestina, S. bracteata) on Staphylococcus aureus, Escherichia coli and Pseudomonas aeroginosa. The antibacterial activity of water extracts of the studied species on the bacterial strains was examined using well diffusion method and minimum inhibitory concentration (MIC). Results showed that only S. bracteata formed growth inhibitory zone (9 mm) on Staphylococcus aureus. The extracts of all three plants formed growth inhibitory zone on E.coli and P. aeroginosa. The extract of S. bracteata was more effective than that of the other species. Results for MIC also showed that the extracts of S. perspolitana had the lowest effect on St. aureus and its MIC was observed in a concentration of 1024 µg/ml. The extracts of this species had the inhibitory effect in a concentration of 256 µg/ml. The uppermost inhibitory effect was provided by the extract of S. bracteata, since the minimum inhibitory concentration of this species for S. aureus was equal to 64 µg/ml; and for the other two bacteria, it was equal to 128 µg/ml. The extracts of S. palaestina had the lowest effect on S. aureus and its MIC was observed in a concentration of 1024 µg/ml. The extracts of this species had an MIC equal to 512 µg/ml for the other two bacteria. It was concluded that S. bracreata could be considered a suitable species with anti-bacterial activities in future researches.
Vida Tafakori, Nasim Nasiri,
Volume 6, Issue 4 (1-2020)
Abstract
Plants have been used as medicines in the treatment of diseases from the past to present. In this research, the anti-microbial effects of aqueous and methanolic extracts of Erythrostemon gilliesii were studied. For this purpose, fresh flowers were ground and then macerated in methanol 100% and water overnight. After the evaporation of solvents, anti-microbial activities of the concentrated extracts were evaluated by the well-diffusion method on Klebsiella pneumoniae, Pseudomonas aeroginosa, Methicilin resistance, Staphylococcus aureus, Bacillus subtilis and Candida albicans. The results showed that the extracts were effective on different bacteria and yeasts. In order to determine the minimum inhibitory concentration (MIC) and minimum biocidal concentration (MBC), anti-microbial tests were performed in micro-plates. Subsequently, the results indicated that the extracts were stable at different temperatures. The aqueous and methanolic extracts of the flowers of E. gilliesii had exhibited anti-microbial effects against important infectious microbes and could be introduced as an excellent source for anti-microbial agents.
