An investigation on the effect of alcoholic and aqueous extracts of Dorema aucheri (Bilhar) on some pathogenic bacteria in vitro

       Dorema aucheri is a plant that grows in Iran. In Persian it is called (Bilhar). This experimental study was carried out at Ferdowsi University of Mashhad in 2014. After collection and preparation of aqueous and ethanolic extracts of Dorema aucheri (Bilhar), The antibacterial activity of ethanolic and aqueous extracts of Bilhar was evaluated against 7 laboratory strains of microorganisms, including 4 Gram positive (Staphylococcus aureus, Streptococcus pyogenes, Bacillus cereus and Bacillus subtilis) and 3 Gram negative bacteria (Escherichia coli, Pseudomonas aeruginosa and Proteus vulgaris). Its effects against human pathogen microorganism were determined using “Spreading of the Extract on Medium Surface” and “Disk Agar Diffusion Method”, Minimal Inhibitory Concentration (MIC) and Minimum Lethal Concentration (MLC) were determined for this extract. Collected data were analyzed by SPSS software using one-way ANOVA. The zone of inhibition for the ethanolic extract varied from 8 mm for P. aeruginosa to 24 mm for S. pyogenes and from 7 mm for P. aeruginosa to 19 mm for S.pyogenes in the aqueous extract. The minimum inhibitory concentration (MIC) of the extracts ranged between 2 mg/ml and 64 mg/ml while the minimum lethal concentration (MLC) ranged between 4 mg/ml and 256 mg/ml. Among of tested strains, P. aeruginosa has maximum MIC and MBC. 30 and 40 mg/mL Concentrations of Redcurrant have significant antimicrobial effect on bacteria. Antibacterial effect of extracts was decreased with decrease of extract concentration in disk. According to result, ethanolic extract of Dorema aucheri have antimicrobial effect on growth of all of the strains exposed analyzes and antimicrobial effect of that was maximum on Gram-positive bacterum of S. pyogenes. P. aeruginosa showed the highest level of resistance against the aqueous and ethanolic Bilhar extracts. The present study demonstrated that the ethanol leaf extract of Dorema aucheri hold an excellent potential as an antibacterial agent.

Antimicrobial effect of Carboxy Methyl Cellulose (CMC) containing aqueous and ethanolic Eucalyptus camaldulensis L. leaves extract against Streptococcus pyogenes, Pseudomonas aeruginosa and Staphylococcus epidermidis

Oil from the eucalyptus tree (Eucalyptus camaldulensis L.) is used today in many over the counter cough and cold products, to relieve congestion. Eucalyptus oil is also used in creams and ointments to relieve muscle and joint pain, and in some mouthwashes. In this study Eucalyptus camaldulensis leaves extracted with water and ethanol 96°and the antimicrobial effects of extracts were evaluated by “using the method of Collins” and “disk agar diffusion method”. Antimicrobial properties of Carboxy Methyl Cellulose (CMC) films containing 20, 40, 60, and 80 mg/ml concentration of the extract studied against on Streptococcus pyogenes PTCC 1447, Pseudomonas aeruginosa PTCC 1310 and Staphylococcus epidermidis PTCC 1435. The results showed that aqueous and alcoholic extract were quite effective in 2000 μg/ml concentration on Streptococcus pyogenes and Staphylococcus epidermidis and have inhibition effect, while both extracts have no certain antimicrobial effect on Pseudomonas aeruginosa. Minimum Inhibitory Concentration (MIC) of ethanolic extract of Eucalyptus camaldulensis leaves were performed for each microorganism. Minimal Bactericidal Concentration (MBC) for bacteria was performed using the dilution method. The edible films containing mangrove extract presented more effective impact on the growth of Streptococcus pyogenes than Pseudomonas aeruginosa (p<0.05). The result indicates extracts of Eucalyptus camaldulensis leaves have the greatest effect on gram-positive bacterium Streptococcus pyogenes. As a result, aqueous and ethanloic extracts of Eucalyptus camaldulensis leaves, have been strong antimicrobial activity against many food pathogen bacteri

Analysis of different signal peptides for the secretory production of Ama r 2 in gram-positive systems (Lactococcus lactis)

Prokaryotic systems have been considered the most affordable and simplest hosts which are being employed to express recombinant proteins such as allergens; nevertheless, without appropriate signal peptide (SP), these systems cannot be used for secretory proteins. Recently, a lot of effort has been put into assessing the potential of gram-positive strains such as lactic acid bacteria for new applications in the production of heterologous proteins. Ama r 2 is a respiratory allergen from Amaranthus retroflexus, whose recombinant production in the probiotic host could be introduced as a specific and effective way to rapid diagnosis and immunotherapy of this allergy. Consequently, the production of this recombinant protein using the prokaryotic system, requires a suitable SP to protect disulfide bonds and to prevent misfolding. This study was designed to predict the best SPs for the expression of Ama r 2 protein in Lactococcus lactis as the host. In this study, 42 signal sequences were selected from SP databases and the most important features of them were evaluated. First, n, h and c regions of the SPs and their probabilities were investigated by signalP software version 4.1. Then, their physicochemical properties were evaluated by Portparam and SOLpro. Moreover, the secretion sorting and sub-cellular localization sites were evaluated by PRED-TAT and ProtcompB software programs. The results revealed that yjgB, entC2 (Entrotoxine type C-2), ent B (Entrotoxine type), blaZ (Beta lactamase), dex (number 21), blm (Beta lactamase 2), dex (Dextranase; number 20) and number 26 were introduced theatrically as the best SPs to express Ama r 2 in Lactococcus lactis

Gamma-aminobutyric acid production by Lactobacillus brevis A3: Optimization of production, antioxidant potential, cell toxicity, and antimicrobial activity

In this study, whey powder was used as the basic compound for fermentation culture and the production of bioactive gamma-aminobutyric acid (GABA) compound. GABA is a nonprotein four-carbon amino acid that inhibits stress signals by preventing brain signals, reducing stress, and being effective in treating neurological disorders and decreasing the growth of cancer cells. Due to the side effects caused by the chemical type of GABA, the biological production of GABA has attracted. Three levels of whey powder (5%, 10%, and 15%), and monosodium glutamate (MSG) (1%, 3%, and 5%) were selected at temperatures (25, 30, and 37°C) and after fermentation, the presence of GABA in the culture medium was examined by thin-layer chromatography. The optimal amount of GABA was measured by using high-performance liquid chromatography. The results of the central composite design of the response surface methodology at a significant level of 95% showed that the optimal treatment was 14.96% whey powder, 4.95% MSG at temperature of 37°C and fermentation for 48 hr and under these conditions, GABA production was 553.5 ppm. The results of the fermented extract tests showed that the highest antimicrobial activity was on Escherichia coli and the highest free radical scavenging was 59.67%. The IC50 level in the Caco-2 cancer cell cytotoxicity test was 39.5 mg/ml. According to the results, the combination of whey with MSG can be used as a cheap substrate to produce a valuable bioactive GABA product, and the cellular extract of this fermentation can also be used as an antimicrobial and antioxidant compound in food and pharmaceutical formulations

Probiotic Bacillus strains inhibit growth, biofilm formation, and virulence gene expression of Listeria monocytogenes

This research aimed to evaluate the probiotic potential and anti-biofilm properties of Bacillus species isolated from dairy sludge, namely Bacillus subtilis GS3 (DS-1), Bacillus cereus BF2 (DS-2), Bacillus velezensis DM (DS-3), and Bacillus thuringiensis JB (DS-4). These strains exhibited tolerance to gastrointestinal fluids, bile salt, phenol, NaCl, and temperature variations. Moreover, they demonstrated notable cell surface hydrophobicity (70.80–89.30%), auto-aggregation (79.30–92.70%), and cholesterol removal (20.12–59.46%). Additionally, the strains displayed antioxidant activity and susceptibility to a wide range of antibiotics. The cell-free supernatants (CFS) of the strains exhibited inhibitory effects against Listeria monocytogenes ATCC 19115, with minimum inhibitory concentrations (MIC) observed at 12.5%, 25%, 25%, and 50% v/v for DS-1, DS-2, DS-3, and DS-4, respectively. The CFS also showed degradation and inhibition of L. monocytogenes biofilms, affecting adhesion, hydrophobicity, auto-aggregation, and exopolysaccharide production. Notably, DS-1 CFS suppressed the expression of genes associated with biofilm formation in L. monocytogenes, including those related to quorum sensing, virulence factors, and flagella. The antibacterial activity of CFS against L. monocytogenes was further confirmed by scanning electron microscopy. Particularly, the CFS of Bacillus spp., especially B. subtilis GS3, exhibited a strong inhibitory effect on the biofilm formation of L. monocytogenes

Identification of Chemical Compounds, Antioxidant Potential, Phenolic Content and Evaluation of Inhibitory and Bactericidal/Fungicidal Effects of Ginger Essential Oil on Some Pathogenic Microorganisms in Vitro

Background and Objectives: Ginger (Zingiber officinale) has been used as medicine and spice in Iran, China, and India since ancient times. Currently ginger is used in many foods, beverages and pharmaceutical agents. The purpose of this research was to evaluate the antibacterial and antifungal activities of ginger essential oil on some pathogenic strains and to determine the chemical compounds, total phenolic content, and antioxidant activity of the ginger essential oil using 2,2-diphenyl-1-picrylhydrazyl.   In this experimental study, identification of chemical compounds of the ginger essential oil and their quantitative measurement was performed using gas chromatography and gas chromatography- mass spectrometry devices. The antimicrobial properties were determined by various qualitative and quantitative methods [disc diffusion agar, minimum inhibitory concentration (MIC), and minimum bactericidal/fungicidal concentration (MBC/MFC)]. Measurement of total phenol and antioxidant potential were carried out by Seevers and Daly colorimetric and radical scavenging methods, respectively. The data were analyzed using one-way ANOVA and Tukey test.   In this study, the highest and the lowest diameters of the inhibition zone at the concentration of 100mg/ml were observed for Candida albicans and Salmonella typhi, respectively. The MIC of the ginger essential oil was equal to 50, 50, 25, 6.25, 12.5, 12.5, 6.25, and 6.25mg/ml for Pseudomonas aeruginosa, Salmonella typhi, Escherichia coli, Staphylococcus aureus, Listeria innocua, Bacillus cereus, Candida albicans, and Aspergillus niger, respectively. The MBC/MFC of the essential oil, were higher than MIC. Zingiberene (29.48%) was the major compound in the ginger essential oil, and the antioxidant activity (IC50) and total phenolic content of ginger essential oil were equal to 93.45μg/ml and 76.65 mg GAE/g, respectively. Conclusion: The results of the current study showed that the effect of ginger essential oil on Gram-positive bacteria was higher as compared to Gram-negative bacteria. Therefore, clinical trials are suggested for future researches

Optimization of gamma‐aminobutyric acid production by Lactobacillus brevis PML1 in dairy sludge‐based culture medium through response surface methodology

Abstract Gamma‐aminobutyric acid (GABA) is a pharmaceutical, bioactive amino acid that can produce by some species of Lactic Acid Bacteria (LAB). For the first time, we evaluated the production of GABA by Lactobacillus brevis PML1 in the medium that contain the contaminant food bio‐product like dairy sludge and soybean meal. GABA production was analyzed by chromatography (TLC, HPLC) and the features of fermented extract which contains this amino acid were evaluated. The results of Response Surface Methodology (RSM) of Central Composite Design (CCD) at p < .05 showed 300 ppm of GABA production in optimal treatment including 14.77% dairy sludge powder, 6.27% soybean meal, and 0.49% ammonium sulfate (32°C for 120 hr fermentation). The results of fermented extract also showed the acceptable antimicrobial, antioxidant, and toxicity (against cancer cell) properties. Also, L. brevis PML1has not shown any hemolytic or DNase activity which confirm its safety aspects. According to the results, this new culture can be used as a cheap substrate to biological production of GABA, by L. brevis PML1 in various food and pharmaceutical formulations

Oral Immunotherapy Using Probiotic Ice Cream Containing Recombinant Food-Grade Lactococcus lactis Which Inhibited Allergic Responses in a BALB/c Mouse Model

This study was conducted to evaluate the effects of recombinant probiotic bacteria as a candidate for oral vaccine with the potential of treating allergy to Amaranthus retroflexus pollens. The main gene of this allergen, Ama r 2, was cloned into the food grade plasmid pNZ7025 and then was electrotransformed into the food grade Lactococcus lactis NZ1330. No expression was observed in the primary structure due to the distance between the ribosome binding site and the start codon. Therefore, the vector structure was corrected using the site-directed mutagenesis (SDM) technique. The cell extract of this strain was used for assessing the expression of the recombinant allergen in western blot analysis, and the existence of this protein with a molecular weight of 14.2 kDa was confirmed. To evaluate the efficacy of this strain in the treatment of allergies as an oral vaccine, probiotic ice cream was prepared. After the sensitization of mice, the treatment was performed by oral immunotherapy for 4 weeks, 4 to 5 times per week. 20 μl of functional ice cream with 1012 CFU/ml of r-L. lactis NZ1330 significantly reduced the serum IgE level. The levels of IFN-γ and TGF-β cytokines increased in the 20 μl ice cream treatment group as well as 40 μg/ml pure allergen compared with the PBS-treated group, and IL-4 cytokine levels decreased compared with the PBS-treated group. Overall, 20 μl ice cream with 1012 CFU/ml of the recombinant bacteria resulted in the best performance in terms of improving allergies to Th1 and Treg responses

Identification of phytochemical, antioxidant, anticancer and antimicrobial potential of Calotropis procera leaf aqueous extract

Abstract Since the dawn of civilization, people have turned to plants as a safe and efficient form of treatment for a variety of diseases. It has long been known that Calotropis procera has the potential to treat a number of diseases. In this study, the C. procera leaf aqueous extract was obtained using the maceration method, and p-coumaric was found to be the main compound. The extract was rich in phenols (174.82 mg gallic acid equivalent/g) and flavonoids (1781.7 µg quercetin equivalent/g). The extract had high antioxidant properties, as indicated by the IC50 values obtained for 2,2-diphenyl-1-picrylhydrazyl (DPPH) (366.33 μg/mL) and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid (ABTS) (169.04 μg/mL), as well as the ferric ions reducing antioxidant power (FRAP) (1.67 μg ascorbic acid equivalent/g of the extract). The cytotoxicity of the extract was evaluated against the survival of HT 29 cells, and the IC50 was found to be 236.87 μg/mL. The most resistant and sensitive strains to the extract were Escherichia coli and Staphylococcus aureus, respectively. The morphological changes of these strains were demonstrated through scanning electron microscopy and confocal laser scanning microscopy. The C. procera extract could be therefore used as an antioxidant, antimicrobial, and anticancer agent