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The antibiotic properties of eight cyanobacteria (blue-green algae) species from Anzali Wetland was investigated on several bacterial species through vacuum distillation and simple mechanical methods. The result showed that Anabaena sp., A. variabilis, A. flos-aquae and Aphanizomenonflos-aquaehad negative effect on the growth of Staphylococcus aureusandA. flos-aquaeand A. oscillaroideshad negative effects on the growth of E. coli. The growth of Candida albicans yeast was greatly reduced by Aphanizomenonflos-aquae, A. variabilis, and A. oscillaroides. Among the investigated algae only A. oscillaroides could reduce the growth of Pseudomonassp. 

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The main goal of this study was to evaluate the antimicrobial activity of Ziziphora clinopodioides against some food spoilage and pathogenic bacteria and determine Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC). Extract of Ziziphora was tested for its growth inhibitory and bactericidal effect on 6 Gram-negetive (Enterobacter aerogenes, Escherichia coil, Klebsiella pneumoniae, Salmonella enteriticlis, Shigella dysenteria and Pseudomonas aeroginosa) and 3 Gram-positive (Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus) species. Minimum inhibitory Concentration (MIC) was determined using dilution method and minimum bactericidal concentration(MBC) was taken from the concentration of the lowest dosed test tube showing no growth on subcultured. All of microorganisms were inhibited by the extract of Ziziphora clinopodioides except Pseudomonas aeroginosa. The MIC and MBC for Gram-negetive bacteria, including Enterobacter aerogenes, Escherichia coil, Klebsiella pneumoniae, Salmonella enteriticlis and Shigella dysenteria were 1000-2000 μg/L. The MIC and MBC for Gram-positive bacteria, including Listeria monocytogenes, Staphylococcus aureus and Bacillus cereus, were 1000-4000 μg/L. Acording to the results of this study, It is applicable to use extract of Ziziphora as the natural preservatives and flavoring agents in food products.

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The antimicrobial and physico-mechanical properties of fish gelatin-alginate film incorporated with oregano (Origanum vulgare L.) essential oil (OEO) were assessed. The blended films were prepared with 75% fish gelatin and 25% sodium alginate and OEO (0, 0.5, 1.0, 1.5%) was added to the film solutions. Results showed that adding 0.5% OEO into films improved tensile strength about 2.54 MPa compared to the control films. The incorporation of 1.5% essential oil decreased tensile strength and the elongation percentage by 3.16 MPa and 15.59%, respectively; water vapor permeability, viscosity and opacity also significantly declined (P < 0.05). Scanning electron microscopy (SEM) of the surface of the film confirmed these results. Although 1.5% OEO-films showed higher antimicrobial activity, fish gelatin-alginate films incorporated with lower level of OEO can be can be more appropriate for food preservationl.

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Aims: Essential oils are a complex of volatile compounds obtained from different parts of plants. Cinnamon (Cinnamomum zeylanicum) essential oil (EO) is known as a suitable source of antibacterial compounds. The aim of present study was to investigate the antibacterial activity of cinnamon EO and ZnO nanoparticles (NPs) against 2 strains of Listeria monocytogenes.
Materials & Methods: In this experimental study, 2 strains of L. monocytogenes (a standard strain and a fish isolated strain) were used. The antibacterial activity of cinnamon EO and ZnO NPs was assessed by well diffusion test. The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of cinnamon EO and ZnO NPs were also determined using broth macrodilution method.  Moreover, the antibacterial properties of cinnamon EO and ZnO NPs were investigated in a liquid medium. The data were analyzed by SPSS 19 software, using one-way ANOVA and Tukey's post hoc tests.
Findings: The Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) of cinnamon EO were 16µl/ml and 64µl/ml, respectively. Furthermore, the MIC and MBC of ZnO NPs were 12.5mg/ml and 25mg/ml, respectively. The bacterial population significantly decreased with increasing the ZnO NPs and the cinnamon EO concentrations (p<0.05) and during cold storage, there were significant differences between the 2 strains.
Conclusion: Cinnamon essential oil and ZnO nanoparticles have strong antimicrobial effects against L. monocytogenes, so that the cinnamon essential oil shows bacteriostatic effects on Listeria, but ZnO nanoparticles show bactericidal effect.

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  Phenolic compounds, especially those of plants origin, are an essential part of the human diet, and are of considerable interest due to their antioxidant properties. The total phenolics content (TPC) and antioxidant and antimicrobial activities of pistachio green hull methanolic extracts of five different cultivars (Fandoghi, Kaleghochi, Ahmadaghai, Forotani and Seyed ali aghai) were studied. TPC ranged from 15.3 mg/g of GAE (cv. Kaleghochi) to 31.1 mg/g of GAE (cv. Ahmadaghai). The antioxidant capacity of extracts was assessed through DPPH and ABTS methods. A concentration-dependent antioxidative capacity was verified in both methods for all the cultivars. Antioxidant activity of Ahmadaghai cultivar in both methods was more than the other cultivars. The antimicrobial capacity was screened against Gram positive and Gram negative bacteria, and fungi. All the extracts inhibited the growth of Gram positive bacteria of Bacillus cereus and Staphylococcus aureus. Bacillus cereus was more susceptible than Staphylococcus aureus for all the extracts. The results obtained in this study showed that pistachio green hull can be used as a cheap and easily accessible source of natural bioactive compounds.

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In this research, antimicrobial activity of extract of Salvia leriifolia were investigated with different concentrations of the extract (5000, 10000, 15000 and 20000 mg/kg) on Staphylococcus aureus count and Total viable count in hamburger at different time intervals: after treatment (day 0) and after storage for 15, 30 and 45 day at -12^˚C, all microbiological analyses performed at 3 replication. The results showed that both of microbial total count and the number of Staphylococcus aureus in all samples with different concentrations of extract, decreased during storage. This decreasing effect was significant on day 15 and 30 for Staphylococcus aureus and total count, respectively. Our data also showed that the extract of Salvia leriifolia at highest concentration (20000 mg/kg) caused maximum reduction compared to other concentrations and extract at lowest concentration (5000 mg/kg) was less effective in initial Staphylococcus aureus population and microbial total count. These data indicate that Salvia leriifolia extract can exhibit antimicrobial activity against Staphylococcus aureus; so it can be considered as an alternative natural preservative in food products.

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Steroids are one of the most important and abundant secondary metabolites of marine sponges. The aim of this study was to investigate the antibacterial properties of steroidal fractions derived from the Persian Gulf sponge Axinella sinoxea. Extraction was first done by Acetone and then the fractions were separated through column chromatography with silica gel. Identification of steroidal fractions were done by thin layer chromatography (TLC) and gas chromatography coupled with mass spectrometry (GC–MS). Then, antibacterial properties of steroids were identified and minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) were investigated by tubular dilution. Two types of steroids including Stigmasta-5,24(28)-dien-3-ol,(3β-24Z) and Ergosta-5,22-dien-3-ol,(3β,22E,24S) were determined. The extracted steroids showed different results regarding the growth inhibition and bactericidal effect on Gram negative (Escherichia coli, Klebsiella pneumoniae and Vibrio harveyi) and Gram positive (Micrococcus roseus and Staphylococcus aureus) bacteria at different experimental doses. In conclusion, promising results were found regarding the antimicrobial effects of the extracted steroids of the marine sponge from Larak island A. sinoxea. These findings reveal the necessity of more comprehensive investigations for the synthesis of pharmaceutical and antibiotic materials from the  bioactive compounds.

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Squalene is an unsaturated triterpene hydrocarbon and is a precursor of steroids and cholesterol with antioxidant properties. The aim of this study was to isolate the squalene from the liver of the Persian Gulf spot tail shark Carcharhinus sorrah and to investigate its antimicrobial activity. Extraction was first done by methanol 70% and then, the squalene was separated through column chromatography with silica gel. Identification of the extracted squalene was done by thin layer chromatography (TLC) and gas chromatography coupled with mass spectrometry (GC–MS). Antibacterial properties of the squalene were identified and minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were investigated by tubular dilution. Identification of the extracted compounds by GC-MS confirmed the presence of the squalene in the shark liver. Antibacterial studies showed that the squalene inhibited the growth of Gram negative (Escherichia coli, Klebsiella pneumonia and Vibrio harveyi) and Gram positive (Micrococcus roseus and Staphylococcus aureus) bacteria. Therefore, this metabolite has the potential to be more investigated for developing new antimicrobial compounds.

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In this study, the aerial parts of Pimpinella puberula were collected from Ramhormoz and Mashhad (Khuzestan and Khorasan Provinces) at the vegetative, flowering and seeding stages. Essential oils from the whole aerial parts as well as stem/leaf, inflorescence, unripe and ripe seeds, were isolated by hydro-distillation. The yields of essential oil obtained from the Ramhormoz samples were 0.49%, 0.31%, 3.81%, 6.01% and 1.80% w/w, and from those from Mashhad were 0.96%, 0.87%, 3.59%, 6.94% and 4.96% w/w, respectively. The oils from different parts of plant were also analyzed by GC and GC/MS. Limonene was the major constituent in all the oils (21.7%-82.4%), followed by pregeijerene (14.6%-55.4%) and geijerene (7.2%- 11.7%). Methyl eugenol and elemicine, however were only found in the Ramhormoz oil samples. The antimicrobial activity of the oils was determined using the disk diffusion method against Gram positive bacteria (Bacillus subtilis, Bacillus cereus, Micrococcus luteus and Staphylococcus aureus), Gram negative bacteria (Yersinia entrocolitica, Klebsiella oxytoca, Serratia marcescens, Escherichia coli and Pseudomonas aeruginosa) and yeast (Candida albicans). Results showed a significant difference between Gram positive and Gram negative bacteria in their susceptibility to the oil, although Gram positive bacteria were more susceptible to the antimicrobial activity of P. puberula oil. In addition, the antimicrobial activity of samples collected from Ramhormoz were more than of those from Mashhad.

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Chemical preservatives are usually used to reduce or eliminate pathogenic or spoilage microorganisms but their inordinate applications have resulted in toxigenic residuals and adverse effects on consumers, So many researches have been done to substitute the chemicals with naturally occurring compounds, especially plant essential oils. In this study, the chemical compositions of essential Thymus kotschyanus were identified with set GC-MS. Then organoleptic properties, microbial and physicochemical quality of Doogh sample prepared with adding different concentration Thymus kotschyanus essential oil were investigated during 14 day storage. Results of GC-MS analysis indicated that thymol (51.1 %), p-cymene (13.78 %) and γ-terpinene (9.03 %) comprised the highest amount of this EO. T. kotschyanus EO destroyed E.coli O157:H7 in addetive low concentrations to Doogh in same the early days and the MIC that  determined by the micro dilution method was 470µg/ml. Based on the results, essential oil doesn’t have significant changes in Doogh physico-chemical properties excepion total solid that essentail Doogh free comparsion with Doogh contain 100 and 200 ppm make significant changes(p<0.05), the Doogh that contain 50 ppm was accepted by panelist. The addition of this EO has no adverse effect on the physicochemical and organoleptic properties of Doogh, also this EO effective substances could be purified and used as natural antibacterial agent, solely or along with others techniques, to prolong food shelf life.

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  With emerging of infectious diseases and spread of antibiotic resistant strains, use of antimicrobial compounds with plant origin seems necessary. In this study, ethanolic extract of Cordia myxa fruit was used to evaluate antimicrobial effects against microorganisms including Bacillus cereus, Staphylococcus aureus, Escherichia coli, Salmonella typhi, Aspergillus niger and Candida albicans. Ultrasound-assisted extraction was performed to investigate three independent variables: time (5- 40 min), temperature (20- 50°C) and sonic power (20- 100%). Response surface methodology was also employed to optimize multiple variables to predict the best process conditions. Antimicrobial activity was done by methods including disk diffusion agar, pour-plate, minimum inhibition concentration and minimum bactericide (fungicide) concentration. The results showed that the highest amount of extraction rate of ethanolic extract which was equal to 8.5%, was obtained in extraction time of 39.8 min, temperature of 42.2°C and sonic power of 94.4%.In all above-mentioned methods, inhibitory effect of optimum ethanolic extract was more significant againstBacillus cereus, Staphylococcus aureus and Candida albicansthan other strains (p≤0.05).

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     In this study, antimicrobial activity of lactic acid bacteria isolated from traditional Kurdish cheese was evaluated. At first, cell free culture supernatant was prepared, and then divided into three groups (control, treated by heat and treated by NaOH). Antimicrobial activity of supernatant treated or no treated was investigated utilizing Agar diffusion, Disk diffusion and Minimum Inhibition Concentration. In addition, coaggregation of lactic acid bacteria against pathogens was determined. Results showed native lactic acid bacteria were suitable antimicrobial activity in comparison to commercial lactic acid bacteria. Heating of supernatant hadn’t effect on antimicrobial activity, while treating by NaOH didn’t show antimicrobial activity. In addition, native lactic acid bacteria didn’t show significant difference in minimum inhibition concentration with commercial lactic acid bacteria. Native lactic acid bacteria also have a suitable coaggregation with pathogens. Results of this study showed native lactic acid bacteria isolated from traditional Kurdish cheese can be used as natural antimicrobial agents.

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In this research, a novel formulation of sponge cake was studied. Instant Tea Powder (ITP) with high ester-catechins content was used to replace 0, 7.5, 12.5, and 17.5% of flour to make sponge cakes, hereafter referred to as the control, ITP1, ITP2, and ITP3, respectively. The microbiological analysis and lipid oxidation experiments were conducted and the odor, flavor, color, chewiness, and overall acceptability of different samples were assessed by sensory evaluation. There was significant difference between ITP2 and the control in hedonic sensory evaluation results, whereas, ITP3 was rated lowest in sensory evaluation results. The results also showed the sponge cakes with ITP had good antimicrobial and antioxidant activity compared with the control, and the shelf life of ITP-treated cakes could be extended as a consequence.

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Chicken meat is highly perishable and quickly spoiled under inappropriate storage. Use of natural extracts is one of the preservation methods of this product. This research was done to evaluate savory extract effect on shelf-life of fresh chicken meat at refrigeration temperature. Chicken pieces were kept for 2 hours in 1, 2 and 3 % solutions of extract and physicochemical analysis including optical properties, pH, TBARS and microbial analysis including total count, coliform and staphylococcus aureus and sensory analysis were done during 1, 3 and 5 days. TBARS results showed that meat oxidation significantly decreased from 0.109 to 0.046 mg MDA/kg comparing to control for 5% coating. Lowest microbial load was seen in 5% coating and decreased from 6.71 to 5.69 log cfu/g. except 5% treatment at 3 and 5 days no significant difference was seen between coated samples and control. Overally, alcoholic extract of savory comparing to control increased shelf-life more than 2 days and could be used for preserving chicken meat.

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The aim of this study was to evaluate the chemical compositions and antimicrobial activity of Satureja hortensis essential oil against Escherichia coli ATCC 25922, Pseudomonas fluorescens OS8, Alternaria alternata PTCC 5224 and Staphylococcus aureus ATCC 25923 in vitro. In this study, S.hortensis essential oil was purchased from Barij Essence Pharmaceutical Company (Kashan, Iran). The chemical analysis of the essential oil was performed by using Gas chromatography/ mass spectrophotometer (GC/MS). The antimicrobial activity was determined through agar diffusion method (well and disc) and broth micro-dilution based on the CLSI protocol . The results showed that the main compounds in the oil were carvacrol (37.83%) and Isopropyl Myristate (59.14%). The oil showed activity against all tested strains. In all treatments, Gram-negative strains tested were more resistant to the antimicrobial activity of essential oil. Minimum inhibitory concentration (MIC) of S.hortensis essential oil on the Escherichia coli, Pseudomonas fluorescens, Staphylococcus aureus and Alternaria alternata was 2 , 1 , 0.5 and 1( mg/ml) respectively. The agar difiusion tests showed, the reduction of essential oil concentration significantly reduces the diameter of inhibition zone for all tested microorganisms. According to the result of this study and increasing resistance of bacteria to chemical antibiotics, it is recommended that more studies on this plant and antibacterial compounds are needed for treating infections.

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Essential of replacing natural compounds with synthetic ones has become more important. Participation of phenolic compounds in natural plant sources in antioxidant and antimicrobial activities caused to determine not only total phenolic and tocopherol compounds, but also antiradical capacity via three various methods such as free radical scavenging DPPH, ferric reducing power FRAP and beta carotene bleaching power of maceration (SO) and subcritical water extraction (SWE) methods of cinnamon extract further than antimicrobial properties of it on both gram negative and positive bacterium. Results proved various amounts with significant difference of total phenolic and tocopherol compounds of two various extraction methods. While SO-extract contained higher phenolic compounds, higher total tocopherol compounds were measured in SWE-extract. Results of all three antioxidant assays indicated that both extracts proved different antioxidant power comparing with TBHQ. The lowest concentration of SO-extract (500ppm) had a bactericide effect on all investigated bacterium in this work.  Whereas, 500 ppm of SWE-extract was able to effect only Staphylococcusaureus as a gram positive bacteria, but not others.

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According to various reported problems, consumers' interest for using natural food additive and preservative agents instead of synthetic ones has become inevitable. In this paper, after determining the total phenolic compound, antioxidant activity of samples was investigated using three various methods of DPPH, FRAP and B-carotene bleaching power, and then, total tocopherol of the samples was measured. Results proved that ultrasound was able to extract more phenolic compounds than subcritical fluid extraction. As the result of that, US-extract expressed more antioxidant power than SFE-extract in all three antioxidant assays. Comparing antioxidant power of both extracts with synthetic antioxidant (TBHQ) proved various results in different concentrations. A part from antioxidant activity, antimicrobial activity (MIC-MBC) of extracts examined on four various bacteria of both gram positive and negative pathogenic ones. Results detected that 500ppm (the lowest concentration of this work) was the same concentration for both MIC and MBC assays.
 

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     The objective of this study was to extract the essential oil of purple basil leaf, to identify its compounds and to investigate its antimicrobial effects on some food-borne pathogenic bacteria through different qualitative and quantitative methods, and eventually, to compare it with some antibiotics including vancomycin and gentamycin in vitro. The essential oil components were identified with GC/MS. The antimicrobial effect of basil essential oil was measured through well diffusion agar (WDA), and finally, the minimum inhibitory concentration (MIC) of the essential oil was determined using microdilution broth and triphenyl tetrazolium chloride. The results revealed that 28 identified compounds constituted 99.28% of the whole essential oil compounds. p-Allylanisole (51.64%) was the most abundant component of the essential oil. In addition, other main components such as n-Tricosane (24.83%) and Linalool (14.81%). In the wall in agar method, the mean free zone diameter was equal to 15.9 mm in the case of Gram-positive bacteria and 11.15 mm in the case of Gram-negative ones. The minimum MIC of purple basil essential oil ranged from 4.6 to 36.8 mg/ml in the case of pathogenic bacteria. Moreover, its minimum bactericidal concentration varied from 4.6 to 73.6. in conclusion, it can be said that purple basil essential oil was effective on Gram-positive bacteria at lower concentrations and could inhibit their growth.

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 Dorema aucheri Boiss. (Apiaceae) is an endemic plant growing in Iran. This plant is used as food and its extracts are recommended for the treatment of a wide range of diseases. To conduct this study, leaf, stem, and flower of D. aucheri were collected from near Yasouje, Iran. Antioxidant and antimicrobialeffects of methanol extracts were measured. Further, total phenolic,flavonoid, anthocyanin, carotenoid, soluble sugar, gallicacid,chlorogenic acid,caffeicacid, andp-coumaric acid contentsof plant methanol extracts were also determined. The results showed that total phenolic, anthocyanin, and soluble sugar in the stem of D. aucheri were 22.72 mg GAE g^-1 dW, 19.33 mg g^-1 dW, and 6.45 mg g^-1 dW respectively, greater than those of the other samples tested. Also, phenolic acids were identified by RP-HPLCand chlorogenic acid was the predominant phenolic compound in the samples. The highest amount of flavonoid (1.95 mg QE g^-1 dW) was observed in the flower. All of the different extracts exhibited a good antioxidant activity based on inhibition of fatty acid oxidation assay. Themaximal inhibition was observed in the leaf (48.52%) and flower (54.24%) of D. aucheri. Ferric reducing antioxidant power (FRAP) was also high in the stem and flower. In addition, the results showed that leaf, stem, and flower extracts had inhibitory activity against four bacteria tested. The highest antimicrobial activity was obtained with flower extract. These results suggest that the methanolic extracts from different parts of D. aucheri are a valuable source of effective compounds. The antioxidant and antimicrobial activity of extracts was correlated with p-coumaric and caffeic acid content.