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

Rosemary (Rosemarinus officinnalis) which is from Laimiaceae genus is almost scattered all over the world and is particularly concentrated in the Mediterranean area and it is also cultivated in Iran. Therefore, due to the importance of this plant and growing interest of people to use less chemical medicines, it seems necessary to examine the studies conducted to study the properties of Rosemary. Carnosic acid is currently an important composition which is a major component of Rosemary secondary composition. The key components which extracted from rosemary included: Cirsimaritin, Diosmin and Genkwanin. Rosemarinic acid is in the form of carnosol and carnosic acid has considerable anti-oxidant properties. Rosemary essence has very good antibacterial properties against many bacteria. In recent years, many researchers have been conducted on its inhibitory effects against microorganisms. Oleanolic acid have anti-viral, anti-oxidant and anti- proliferative properties to protect against anti-oxidative apoptosis. Ursolic acid can also be useful in preventing cancer. Rosemary is non-toxic to human and has no side effects, so that this valuable plant has been superior to some of the common antibiotics. Also, several reviewed studies showed that adding rosemary essence to food samples has a superior effect in reducing the microbial load and increasing the shelf life of foods. Given that anti- inflammatory, anti-oxidant and pharmacological properties of Rosemary with a wide range have been approved. So, this plant can be a suitable choice to be used in the field of pharmacy and food industry. Therefore, it seems necessary and beneficial to conduct further studies on evaluating its anti-microbial and anti-oxidant activities.

Today, due to increase in resistance of antibiotics, it is necessary to find suitable alternatives to natural materials. Algae also have many applications in medicine, pharmacy and the food industry.  Therefore, the present study was performed to investigate the antibacterial activity of red algae Gracilaria gracilis extract. In this study, the active compounds of methanolic extract of red algae G. gracilis were identified by gas chromatography-mass spectrometry (GC/MS). The Antimicrobial effect of algae extract on bacteria were investigated by sequential dilution method. The chemical analysis of the algae extract compounds showed that the major components of the extract were phenylethine, silacyclopntenen, phthalic acid, n-hexadecanoic acid, dibutyl phthalate, phytol and gibberellin. In the study of minimum inhibitory concentration and minimum bactericidal concentration, it was shown that Pseudomonas aeruginosa and Staphylococcus aureus with algae extract with a minimum inhibitory concentration of 6.2 and 112.5 mg/mL, respectively, compared to other studied bacteria, showed more sensitivity. Based on the results, the methanolic extract of red algae G. gracilis had good antimicrobial activity. Therefore, clinical research is necessary for the clinical applications of this extract.

Biological and natural products have been considered as the most important source of medicines from ancient times. The aim of this study was to evaluate the antioxidant, antibacterial and cytotoxicity properties of brittle star Ophiocoma erinaceus. Extracts of brittle star central disk and arms were separated by using three solvent types, n-hexane, ethyl acetate, and methanol. The antioxidant activity of each of the extracts was assessed via measuring of reducing power and total antioxidant capacity. Total phenolic and flavonoid contents were also measured spectrophotometrically. The antibacterial effect against three strains of Gram-positive and one Gram-negative bacteria were also investigated. Cytotoxicity test was carried out using the Artemia larvae. Methanolic extracts were found to have the highest antioxidant activity via both methods, and ethyl acetate extract of arms and methanolic extract of the central disk showed the highest antibacterial activity on Pseudomonas aeruginosa and Serratia marcescens, respectively (P<0.05). The highest toxicity level was also observed for extracts of 500 and 1000 μg/mL concentration respectively. The findings suggest that this species has antioxidant, antibacterial and toxicity properties. Therefore purification and identification of these effective compounds are proposed.

In medicine, nanofiber can be used in wound dressing. The aim of this study was to prepare carboxymethyl cellulose/calcium alginate/polyvinyl alcohol/silver (CMC/Alg/PVA/Ag) nanocomposite by electrospinning method and to investigate its performance as wound dressing. In the present experimental study, CMC biofilm was prepared by solution method. Then, calcium alginate/polyvinyl alcohol/silver (Alg/PVA/Ag) nanofiber was prepared by electrospining method in the optimal conditions and deposited on CMC film. Finally, the possibleof application of the product as wound dressing and its antibacterial and morphological properties, as well as permeability to water vapor were investigated. CMC/Alg/PVA/Ag film had more permeability in comparison to Alg/PVA/Ag nanofibers and less water vapor permeability value in comparison to CMC film. The most sensivity belonged to Escherichia coli and Klebsiella pneumoniae gram-negative bacteria with inhibition zone diameter of 23mm and 24mm, respectively, and Staphylococcus aureus and Staphylococcus saprophyticus gram-positive bacteria with inhibition zone diameter of 21mm and 17mm, respectively, for CMC/Alg/PVA/Ag film. Also, the wound with CMC/Alg/PVA/Ag dressing significantly showed more healing speed in comparison to CMC dressings and CMC/Ag. The use of CMC/Alg/PVA/Ag nanocomposite as wound dressing is possible. This dressing, with pores, allows the vapors to flow through the wound secretions, is impermeable to liquids and bacteria, but is permeable to oxygen and vapor; it is not allergenic and does not cause toxicity and chemical stimulation, transparent dressing and the possibility of seeing the wound is easily possible, it provides the moisture level needed for wound healing, it does not stick to the wound and as a result, its replacement is without pain and cheap.

Algae are composed of a diverse group of various aquatic organisms. Secondary or primary metabolites from these organisms may be potential bioactive compounds of interest for use in the development of new pharmaceutical agents. In this research, four species of marine algae, Ulva lactuca, Padina pavonica, Colpomenia sinuosa and Cystoseira myrica, isolated from Persian Gulf coasts were evaluated for their antimicrobial activities, using disk diffusion and Minimum Inhibitory Concentration assays. Extracts of the algae selected for this study were prepared using methanol, n-hexane and ethyl acetate as solvents. Best results were shown by the ethyl acetate extracts of Ulva lactuca against bacterial strains. Results also indicated that the bacteria were more sensitive against algal extracts than fungi studied. The lowest value for MIC test was belonged to the green alga, Ulva lactuca, in accordance with growth inhibition zone values obtained from disk diffusion assay. Based on present results, gram-positive bacteria were more sensitive to the algal extracts than gram-negative ones.

Resistance of many diseases pathogenic bacteria against synthetic drugs and their side effects ,besides high expense of chemical drugs directed the attention to scientists toward natural and herbal medicines usage. The purpose of this study is to investigate the antibacterial properties of root, leaf and stem hydroalcoholic extract of Dendrostellera lesserti against some human pathogenic bacteria. Dendrostellera lesserti was collected from Hamedan province in 2013. After plant identification, the extracts were prepared using maceration method. The eight positive and negative gram human pathogenic bacteria were tested. For antibacterial properties investigation, agar well diffusion, MIC (serial dilution method) and MBC methods were used. The amount of total phenol was measured by Folin-ciocalteu. The results was statistically analysis using sas 9.2 in factorial with completely randomized design in three replications. Though, the highest growth inhibition zone (18±1.00 mm) in Bacillus subtillis culture in presence of root hydroalcoholic extract, the stem hydroalcoholic extract showed more inhibitory and bactericidal effect on the most bacterial cultures. The amount of total phenol in the root, stem and leaf was measured as, 111.8± 2.69, 79.47±0.55 and 69.16±3.29 (mgGAE/g), respectively. According to the results, the root, leaf and stem hydroalcoholic extracts of Dendrostellera lesserti contain different amount of phenol and plant contains compounds with antibacterial properties. This research can be used as a base in antimicrobial compounds study of this plant.

The emergence of new pathogens and the increase in the number of multidrug-resistant strains in well-established pathogens during the past decade represent a growing public health concern globally. Therefore, it is important to introduce and replace new sources of drug such as medicinal plants with antimicrobial properties. The aim of the present sturdy was to evaluate the antibacterial effects of areal parts extract of Epilobium species collected from Iran. The results revealed that extract of all species studied, except (E. roseum subsp. subsessile) could inhibit the growth of bacteria. Based on our results, gram positive test bacteria showed the most susceptibility to the extracts compared to gram negative ones. None of the extracts could affect the growth of Pseudomonas aeruginosa and Enterococcus faecalis. We found that the willow herb extract inhibited the growth of bacteria in culture more effectively than related common antibiotics. Given that aerial parts of plant extract was utilized for this study, further investigation is recommended to determine which specific part of the plant (i.e., leaves, stem, and flowers) possess the antibacterial properties.

The increases in the microbial antibiotic resistance and decreases in the sensitivity of bacteria to antimicrobial chemical compounds are some concerns of the researchers who look for herbal compounds as antimicrobial properties. The purpose of this study is to investigate the antibacterial and antioxidant properties of leaf and stem extracts of Dendrostellera lesserti against 10 human pathogenic bacteria.

Dendrostellera lesserti was collected from the Alvand Mountain (1961 m height) located at Hamedan province. After identification, the extracts were prepared using maceration method. In this sectional study, antibacterial activity was determined by agar well diffusion method, MIC (serial dilution method) and MBC. The antioxidant properties of these extracts was determined by DPPH method. Also, the amounts of phenol and flavonoid was assayed by Folin-ciocalteu and Aluminum chloride methods, respectively.

The largest growth inhibition zone with 27.3±0.6 mm diameter was observed on Micrococcus luteus culture exposed to ethanolic extract of the stem. The MIC and MBC of the extracted obtained from stem were lower than the leaf extract. Methanolic extract of stem in concentration of 1 mg/ml had the highest scavenging percentage of free radical. The methanol extracts of stem and leaf achieved the highest amount of phenol and flavonoid, 79.4±0.5 (mgGAE/g) and 2.1±0.1(mgQ/g), respectively.

The results of present study showed that alcoholic extract, especially methanol extract, of Dendrostellera lesserti showed antibacterial ability. Since the phenolic and flavonoids compounds have anti bacterial and anti-oxidant properties, the property showed in this study can be because of the presence of these compounds in the tissues studied.