Microbiology
Elaheh Tasallot Maraghi; Nasim Kashef; Ahmad Reza Gohari; Zahra Fekrirad
Volume 28, Issue 4 , September and October 2021, , Pages 556-568
Abstract
Introduction: Staphylococcus aureus is one of the most important pathogenic bacteria in humans. Due to the antibiotic resistance, treatment of staphylococcal infections is difficult. Among the alternative treatment options, plants are considered as a rich source of material with antimicrobial activity. ...
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Introduction: Staphylococcus aureus is one of the most important pathogenic bacteria in humans. Due to the antibiotic resistance, treatment of staphylococcal infections is difficult. Among the alternative treatment options, plants are considered as a rich source of material with antimicrobial activity. The aim of this study was to evaluate of the antimicrobial effects of ethyl acetatic, methanolic and water-methanolic extracts from Satureja khuzistanica, Peganum harmala, Satureja sahendica onplanktonic growth and biofilm formation of S. aureus.
Materials and Methods: The extracts were prepared from different parts of plants and the antimicrobial properties of the extracts were determined by disk diffusion and microbroth dilution method. Also, Crystal violet staining assay was used to evaluate the ability to inhibit biofilm formation of S. aureus strains. Disruption of pre-formed biofilms of S. aureus strains were evaluated following exposure to plant extracts in different concentrations (ranging from 3/125 to 400mg/ml).
Results: The highest inhibitory zones were showed by ethyl acetatic extract of Satureja sahendica (28/6±0.6mm). Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ethyl acetatic extract of S.khuzistanica were 1/562 and 3/125mg/ml, respectively. Besides, methanolic extract of S. khuzistanica was the most effective extract in inhibition of microbial cells attachment to surface (57/89%) and it showed disruption of pre-formed biofilms at the concentration of 50 mg/ml.
Conclusion: The extracts of all mentioned plants had satisfactory antimicrobial effects against the planktonic growth of S. aureus and methanolic extract of S. khuzistanica was effective against biofilm formation of S. aureus.
Microbiology
Morteza Yazdani; Fereshteh Jookar Kashi; Akram Rahimi-Moghaddam
Volume 26, Issue 5 , November and December 2019, , Pages 555-565
Abstract
Background: Considering the adverse effects of synthetic antioxidants, anticancer drugs and antibiotics on human health, in this study, bioactivities of Mentha longifolia essential oils collected from Marivan and Qaza An were examined and compared with each other for identification a natural alternative ...
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Background: Considering the adverse effects of synthetic antioxidants, anticancer drugs and antibiotics on human health, in this study, bioactivities of Mentha longifolia essential oils collected from Marivan and Qaza An were examined and compared with each other for identification a natural alternative of synthetic antioxidants, anticancer drugs and antibiotics.Materials and Methods: Essential oil of M. longifolia leaves and stems collected from Marivan and Qaza An was prepared using solvent-free microwave extraction method. The essential oil components were identified by gas chromatography/mass spectrometry. The antioxidant and cytotoxicity activity of the essential oils were determined via β–carotene bleaching assay and brine shrimp lethality test, respectively. The antimicrobial activity of the essential oils was evaluated by the agar well diffusion method and by determination of minimum inhibitory concentration.Results: The main components of M. longifolia essential oil collected from Marivan were pulegone (81.45%) and isopulegol (8.39%) and the main components of M. longifolia essential oil collected from Qaza An were pulegone (48.29%) and piperitenone oxide (23.53%). The inhibition of linoleic acid oxidation by M. longifolia essential oils collected from Marivan, Qaza An and BHT were 80.02%, 78.59% and 95.50%, respectively. The LC50 of the M. longifolia essential oils collected from Marivan, Qaza An and vincristine sulfate were 53.47μg/ml, 55.96 μg/ml and 0.751 μg/ml, respectively. M. longifolia essential oils had good antimicrobial activity, especially against gram-positive bacteria.Conclusion: M. longifolia essential oils have significant antioxidant, antimicrobial and anticancer activity and can be introduced as alternatives of synthetic antioxidants, antibiotics and anti-cancer drugs.
Omid Azizian Shermeh; Mozhgan Taherizadeh; Moharam Valizadeh; Alireza Zaboli
Volume 25, Issue 2 , May and June 2018, , Pages 279-292
Abstract
Background: In this study antimicrobial activities, antioxidant activities and phytochemical compounds in the essential oil and extracts of Cumbopogon olivieri were studied.Material & Methods: For investigation of phytochemical compounds such as total phenolic and total flavonoid contents in three ...
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Background: In this study antimicrobial activities, antioxidant activities and phytochemical compounds in the essential oil and extracts of Cumbopogon olivieri were studied.Material & Methods: For investigation of phytochemical compounds such as total phenolic and total flavonoid contents in three extracts (Methanolic, ethanolic and aqueous) and essential oil by Folin-Ciocaltiu, Aluminum Chloride colorimetric and GC-MS methods and antioxidant activities of extracts by two methods (DPPH and FRAP) and antimicrobial activities of essential oil and extracts of Cumbopogon olivieri against three bacteria such as Staphylococcus aureus, Bacillus cereus, Escherichia coli and two fungi such as Candida albicans and Aspergillus niger by two methods (well diffusion and Minimal Inhibitory Concentration (MIC)) respectively.Results: The results showed that, the methanolic extract had maximum total phenolic and flavonoid contents and antioxidant activity and aqueous extract had minimum value of this compounds and activity. In investigation of essential oil, three compounds such as piperitone (82.95%), carene (2.493%) and limonene were the major constituents. The results of antimicrobial activity showed that, the essential oil and extracts had good inhibition effect on all of bacteria and fungi and this inhibition depends to concentration.Conclusion: Overall, based on the results obtained, the plant can be a good candidate for the treatment of diseases caused by oxidative stress, and diseases caused by pathogenic microbes. Also due to power up the plant in the elimination of pathogens, could be a viable alternative to antibiotics.
Ali Asghar Ghaderi; Baratali Fakheri; Nafise Mahdinezhad; Saeede Saeedi
Abstract
Backgrounds The current study aimed at investigating the antimicrobial effects of Vulgaris thymus ethanol extract on the important human pathogens.Methods & Materials The thymus alcoholic extract was provided based on a standard protocol. The following standard bacteria were also provided: Streptococcus ...
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Backgrounds The current study aimed at investigating the antimicrobial effects of Vulgaris thymus ethanol extract on the important human pathogens.Methods & Materials The thymus alcoholic extract was provided based on a standard protocol. The following standard bacteria were also provided: Streptococcus pyogenes ATCC 19615, Streptococcus pneumoniae ATCC 49619, S. saprophyticus ATCC15305, Hafnia alvei ATCC 51873, Acinetobacter baumannii ATCC 19606, Enterococcus faecalis ATCC 29212, Proteus mirabilis ATCC 35659, Serratia marcescens ATCC 274, Staphylococcus aureus ATCC 25923.The minimum inhibitory concentration (MIC) of thymus ethanol extract on the bacteria was determined. The linear sensitivity of the bacteria against some antibiotics was also measured by the standard method of Kirby-Bauer disk diffusion. Results The results showed that the thymus leaf alcoholic extract inhibited the bacterial growth in the evaluated concentrations. The MIC of 6/25 ppm was observed effective against S. pneumoniae, H. alvei, P. mirabilis, and S. marcescens.Conclusion The results of the current study indicated the high effect of thymus alcoholic extract on the pathogenic bacteria. However, the medicinal application of plants requires further investigations.
Ali Salehi; Nabi Shariatifar; Aftab Salehi; Alireza Mohammadzadeh
Volume 23, Issue 3 , July and August 2016, , Pages 430-437
Abstract
Background Food-borne pathogens are a group of microorganisms that cause food-borne illness, and the research for finding effective natural products against the infection arisen from these microorganisms is necessary. The purpose of this study was to determine antimicrobial effect of aqueous and ethanol ...
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Background Food-borne pathogens are a group of microorganisms that cause food-borne illness, and the research for finding effective natural products against the infection arisen from these microorganisms is necessary. The purpose of this study was to determine antimicrobial effect of aqueous and ethanol extracts of Rheum ribes on some important foodborne bacteria.Materials & Methods After collecting the leaves and stalks of rhubarb in the spring, its different concentrations of 50, 75, 100, 125, and 150 mg/mL were prepared. Then, antibacterial effect of aqueous and ethanol extracts were determined by the disk diffusion and serial dilution methods.Results Findings showed that aqueous and ethanolic extracts of stalks and leaves of rhubarb have good inhibitory effect on S. aureus and E. coli. The minimum inhibitory concentration (MIC) of the ethanolic leaves and stalks extracts of rhubarb against S. aureus and E. coli were ≤75, ≤50, ≤100, and ≤75, respectively, and MIC of the aqueous leaves and stalks extracts of rhubarb against S. aureus and E. coli were ≤100, ≤100, ≤125, and ≤100, respectively. The minimum bactericidal concentration of the ethanolic leaves and stalks extracts of rhubarb against S. aureus and E. coli were ≤100, ≤75, ≤150, and ≤125, respectively, and aqueous extracts did not have bactericidal effects.Conclusion Extracts of rhubarb leave and stalk showed a good antimicrobial activity against food-borne pathogens. Therefore, they can be used in food preservation systems to inhibit the growth of these bacteria and improve food quality and safety.
Mohammad Bokaeian; Faramarz Dahmardeh; Mohammad Sohrabi; Saeide Saeidi
Volume 22, Issue 5 , November and December 2015, , Pages 780-787
Abstract
Background: Infectious diseases are an important cause of mortality in the world. Because of resistance of some human pathogenic bacteria to antibiotics, use of natural and herbal medicine is increasing to control these factors. The aim of this study is to investigate the antibacterial effects of Ramalina ...
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Background: Infectious diseases are an important cause of mortality in the world. Because of resistance of some human pathogenic bacteria to antibiotics, use of natural and herbal medicine is increasing to control these factors. The aim of this study is to investigate the antibacterial effects of Ramalina hyrcana Sipman lichens against many Gram-positive and Gram-negative bacteria.
Materials and Methods: The lichen ethanol extract was prepared by using a rotary machine. Nine standard strains of Gram- positive and Gram -negative bacteria were cultured in nutrient broth. The minimum inhibitory concentration (MIC) was determined by the micro dilution method.
Results: The results of this study showed that the lichen R. hyrcana extract in different concentrations inhibited both Gram-positive and Gram-negative bacteria. The results showed that the lichen extract of all concentrations inhibited of Staphylococcus aureus. After S. aureus bacteria inhibition, the minimum inhibitory concentrations are for Hafnia and Acinetobacter (12.5 ppm).
Conclusion: According to the results and other reports in this area, lichen R. hyrcana extract could be introduced as a biological control agent. However, for the use of different lichen extracts for clinical application, the chemical analysis of extracts and clinical research is necessary.