جستجوی مقالات مرتبط با کلیدواژه « Antibacterial Activity » در نشریات گروه « زیست شناسی »

Nowadays, the emergence of allergies, side effects of drugs, antibiotic-resistant strains, and the need of body to antioxidants emphasized the importance of herbal medicines.

Therefore, this project aims to investigate the phytochemical extract of hydroalcoholic of Polylophium involucratum harvested from the heights of the Javaherdeh - Ramsar and determine its cytotoxic effects on chronic myeloid leukemia.

To this end, Polylophium involucratum seeds were collected from the heights of the Javaherdeh, Ramsar, and extracted using a microwave assisted extraction. Then, using quantitative and qualitative phytochemical tests, determining antibacterial activity by disk emission method and finally, assessing the effect of cytotoxicity on the category of K562 cancer cells using the MTT method was investigated.

Phytochemical screening of the hydroalcoholic extract of Polylophium involucratum confirmed the presence of secondary metabolites such as flavonoids, terpenoids, coumarins, cardiac glycosides, tannins, phenols, quinones, and saponins. The total amount of phenolic compounds and flavonoid compounds was calculated as 12.93±2 and 7.58±7 mg/ml respectively. The percentage of free radical inhibition was obtained at 57.70±0.5 and the IC50 value was 0.66 μg/ml. The aura diameter of non-growth was observed in Gram-negative Escherichia coli bacteria and Gram-positive Staphylococcus aureus and Bacillus cereus 25, 10, and 10 mm respectively. The results of cellular toxicity also showed that Polylophium involucratum hydroalcoholic extract is dose-dependent, with the highest toxicity effect at a concentration of 50 μg/ml, and the highest bioavailability effect at a concentration of 20 μg/ml in 24 hours, with an IC50 level equal to 50.35±0.03 μg/ml with a meaningful level of 5%.

Based on the obtained results, in general, the use of effective plant compounds is considered one of the most effective strategies in the treatment of cancer, and the secondary metabolites in Polylophium involucratum extract can be a promising method in the treatment of cancer, which requires more studies and experiments are to be done in the future.

This study aimed to investigate the antimicrobial properties of metabolites extracted from cellulose microbiomes to better understand their potential as a source of new antimicrobial agents.

In this observational-analytical study, 50 soil samples were collected from different regions of Tehran province. After culturing, suspicious colonies were phenotypically and biochemically tested, and molecular identification was performed by amplifying the 16S rRNA gene. Primary screening of metabolite production with antibacterial and antifungal effects was done using the Cross-Streak Method. The antimicrobial effect of the extracted metabolite was measured using the well diffusion method and the minimum concentration of growth inhibition. Finally, the chemical composition and potential metabolite substance were determined through high-performance liquid chromatography and mass spectrometry.

Five Cellulosimicrobium isolates were identified using biochemical methods and molecular identity verification. Among the five isolates suspected to be Cellulosimicrobium, strong antibacterial activity was observed in one isolate during the screening stage. Cellulosimicrobium had a strong effect on Escherichia coli and methicillin-resistant Staphylococcus aureus, but no antifungal effect was observed. The structure of the desired metabolite with the formula C14H24N2O7 was identified through HPLC and Mass chromatography analysis.

These findings suggest that Cellulosimicrobium is a promising source for the discovery and development of new antimicrobial agents.

The aim of this study was to assay the antibacterial activity of Scenedesmus obtusus on some pathogenic bacteria. Microalgae S. obtusus were obtained from Algae Bank of Iran, and the methanol, ethyl acetate, chloroform and n-hexane extract of the microalgae were prepared using the maceration method. Bacterial strains were cultured in a solid culture medium, and antibacterial activity of the the different extracts of S. obtusus, were investigated using well diffusion method, and the determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC), against Staphylococcus aureus, Streptococcus agalactiae as gram-positive bacteria and Escherichia coli and Klebsiella pneumonia as gram-negatives. According to the results, methanolic and ethyl acetate extracts of S. obtusus, showed growth inhibitory effects against all examined bacteria at concentrations of 200, 300 and 400 mg/ml. The chloroform extract was effective only against S. aureus and E. coli, but n-hexane extract had no effect against any of the bacteria. The highest inhibitory effect of S. obtusus extract was observed on methanolic extract against E. coli (16 mm), while the least inhibitory effect belonged to ethyl acetate extract against S. aureus (6.8 mm). The results also showed that the extract of S. obtusus contains antibacterial compounds, and the solvent which used for microalgae extraction significantly affected the antibacterial potential of the extract.

Nanoparticles are used as a pharmaceutical tool for infections against microbes and in the near future, there is an urgent need to replace antibiotics with new substances with antibacterial properties. One of the most efficient methods of nanoparticle synthesis is the method of green synthesis of nanoparticles by plants. In this study, an environmentally friendly extracellular biosynthesis method, namely reducing agents of Mentha piperita L. extract, was used to produce gold nanoparticles. The gold nanoparticles were characterized by color changes, the XRD method and the UV-visible spectroscopy and the antibacterial activity of nanoparticles against four species of bacteria (Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Bacillus cereus) investigated through bacteria disc fusion assays. Results showed that due to the reduction of gold ions and the production of nanoparticles, the color of the samples changed from yellow to brown, which indicates the production of a colloidal suspension of gold nanoparticles. The gold nanoparticles have the maximum absorbance at 550 nm, spherical shape and their average size was 2-10 nm. Further investigation revealed that synthesized nanoparticles have relatively antibacterial activity on Escherichia coli, Salmonella typhimurium but have no effect on Bacillus cereus and Staphylococcus aureus. In general, based on the observations of this study, it can be concluded that the aqueous extract of Mentha piperita L. due to its secondary components and antioxidant activity, has high potential in the reduction of gold metal ions as well as synthesis and stabilization of gold nanoparticles. Also, the synthesized gold nanoparticles show relatively good antibacterial activity against some bacteria.

In this study, the effect of different levels of the amino acid methionine on some growth factors, mucosal immunity and antibacterial properties of mucus in Rutilus frisii kutum was investigated. Therefore, first 420 juvenile Rutilus frisi katum with an average weight of 1.24± 0/02 g were prepared, then 35 fish were randomly distributed in 12 tanks with four treatments and three replications. They were then fed at doses of 0, 2/5, 5 and 10 mg / kg methionine for 60 days, respectively. The results of this study showed that different levels of methionine had no effect on whitefish growth indices, so that there was no significant difference between treatments containing different levels of methionine in terms of different growth indices. The highest lysozyme activity was observed at 5% level, and the amounts of alkaline phosphatase and mucus-soluble protein were observed at 10% level. The results showed that the highest antibacterial activity was related to the levels of 5 and 10% of the amino acid methionine. According to the results, it can be said that 5 and 10% levels of the amino acid methionine can be effective in improving the activity of some digestive enzymes (lysozyme, alkaline phosphatase), soluble proteins and antibacterial activity in the study species. Achieving more complete and accurate results requires more research in this area.

Today, the increasing failure of chemotherapy and antibiotic resistance displayed by pathogenic bacteria infectious agents have caused the screening of new secondary metabolites with various chemical structures of marine crustaceans, molluscs and echinoderms with desirable antibacterial activity. This study was designed to determine the antimicrobial effect of muscle wall methanol and acetone extracts of four species of sea cucumber (Holothuria arenicola, H. leucospilota, Stichopus hermanni, S.horrens) in Chabahar coasts on some rainbow trout (Oncorhynchus mykiss) pathogenic bacteria (Lactococcus garvieae, Aeromonas hydrophila, Yersinia ruckeri and Streptococcus iniae).

An experimental study was conducted at in vitro conditions. Experimental variables include sea cucumber species, different concentrations of extracts and bacterial strains. After preparing extracts of mentioned sea cucumber by maceration method, the antimicrobial effect of outcome extracts from their muscle wall were investigated by two different methods disk diffusion and well diffusion.

At acetone extract of S.horrens, the highest growth inhibition zone for Y. ruckeri and A. hydrophila bacteria at 12 mg/mL concentration in disk diffusion method (11.10 and 13.03 mm) were seen respectively. Different concentrations of methanol extract of S. hermanni, H. leucospilota and H. arenicola were inactive on the tested bacteria. While, Minimum Inhibitory Concentration (MIC) of acetone extracts of S.horrens for Y. ruckeri and A. hydrophila was 0.625 and 1.25 mg/mL respectively and Minimum Bactericidal Concentration (MBC) for Y. ruckeri and A. hydrophila bacteria were 2.5 and 2.5 mg/mL respectively in well diffusion method.Generally, it type of extract, sea cucumber species and also bacterium strain are influenced on growth inhibition zone, MIC and MBC. Acetone extract of S. hermanni and S. horrens sea cucumbers can prevent the growth of Y.ruckeri bacterium tested by both methods (disk diffusion and well).