Agar-well Diffusion Assay Research Articles

Phytofabrication of gold and bimetallic gold-silver nanoparticles using water extract of wheatgrass (Triticum aestivum), their characterization and comparative assessment of antibacterial potential

In the present study, gold (AuNPs) and gold-silver bimetallic nanoparticles (Au-Ag BMNPs) were fabricated by using water extract of leaves of Triticum aestivum - a crop plant, and their bactericidal potency was checked against selected pathogenic bacterial strains. The phytofabricated AuNPs and BMNPs were analyzed for their physical attributes using UV–Visible and Fourier transformed infrared spectroscopy, Dynamic light scattering, High-resolution transmission electron microscopy, Energy-dispersive X-ray spectroscopy. HRTEM analysis revealed that both kinds of NPs were highly crystalline in nature and of spherical and oval-shaped. AuNPs size was found in the range of 5-40 nm, whereas BMNPs showed their size in the range of 5-30 nm. HRTEM results were corroborated by DLS results which revealed the average hydrodynamic diameter of AuNPs and BMNPs in the range of 29.08 and 26.56 nm, respectively. UV-visible spectroscopy showed high-intensity single spectral peaks at 540 and 480 nm for AuNPs and BMNPs, respectively. FTIR analysis demonstrated that protein, flavanones, hydroxyl, carboxylate groups, and reducing sugars were responsible for reducing and capping of both NPs. Bactericidal efficiency of synthesized NPs was evaluated using agar-well diffusion and XTT-colorimetric assays against K. pneumoniae, S. typhimurium, E. aerogenes, E. coli, M. luteus, S. aureus, S. mutans and S. epidermidis. K. pneumonia and S. typhimurium were found to be the most sensitive bacteria towards BMNPs-mediated (MIC: 400 µg/ml) and AuNPs-mediated toxicity (MIC: 800 µg/ml). It was observed that BMNPs generally possessed more powerful bactericidal effect against all bacterial strains in comparison to AuNPs. MIC and MBC values were observed in the concentration range of 400 µg/ml-1.5 mg /ml for different bacterial strains. Furthermore, it was demonstrated that phytosynthesized AuNPs have their own bactericidal effect, but at higher concentrations (>100 µg/ml), and bactericidal effect of BMNPs was due to the synergistic effect of both Ag and Au ions, which was also observed to be concentration-dependent.

Eco-Friendly Synthesis of Multishaped Crystalline Silver Nanoparticles Using Hill Garlic Extract and Their Potential Application as an Antifungal Agent

Antimicrobial resistance is a global health challenge, and the large loads of biocides dumped into the environment augment the spread of antifungal resistance and environmental contamination. Therefore, eco-friendly antifungal agents must be developed to combat antibiotic resistance and to reduce environmental contamination. In the present investigation, Allium sativum (Hill garlic-Malai Poondu) extract was used as a green resource to achieve silver nanoparticle (AgNP) production. AgNPs were characterized by various spectral and microscopic analyses. In vitro free radical scavenging assays were instigated to determine the antioxidant capacity of the AgNPs, and the antifungal activity was assessed using Agar well-diffusion assay again pathogenic fungal strains. The mean particle size of the AgNPs was calculated as 35.1 nm with face-centered cubic (FCC) structure. AgNPs exhibited free radical scavenging activity against 2,2-diphenyl-1-picrylhydrzyl (DPPH), 2,2-azino-bis (3-etilbenzotiazolin)-6-sulfonic acid (ABTS), and hydrogen peroxide (H2O2) radicals. Scavenging of DPPH radicals by AgNPs was impressive, and an IC50 value of 6.3 ± 0.4 μg/ml was obtained in this assay. Among the tested Candida strains, the order of the least susceptibility on exposure to AgNPs synthesized using Hill garlic extract was as follows: C . g l a b r a t a ≤ C . t r o p i c a l i s ≤ C . p a r a p s i l o s i s ≤ C . k r u s e i ≤ C . a l b i c a n s . The study highlights the synthesis of environment-friendly nanoparticles using Hill garlic extract with enhanced antifungal properties.

Antibacterial efficiency of natural products against multiple-drug-resistant clinical isolates

Background Antibiotic resistance is a global problem that has aggravated recently to threaten humans, cattle, and crops. This has inspired scientists to examine various natural products, herbs, and plants that have been used since antiquity for their valuable medicinal potential. They have not only proven less likelihood to produce resistant strains but also exert a positive effect on beneficial probiotics boosting the general health status of the host.Objective To identify the major multiple-drug-resistant bacteria underlying diabetic foot ulcer infections and screen and select herbs and natural extracts, commonly available in local herbal stores, for their activity against the isolated bacteria.Material and methods Bacteria isolated from diabetic foot ulcers of hospitalized patients were identified according to their morphological and biochemical properties. The isolated strains were tested against extracts of bitter melon, honey, pomegranate peel, myrrh gum, and turmeric powder using the in vitro agar well-diffusion assay technique.Results and conclusion The bacterial isolates were resistant to all of the tested standard antibiotics and identified to belong to five different genera: Gram positive bacteria Staphylococcus aureus and Streptococcus pyogenes and Gram negative bacteria Escherichia coli, Klebsiella pneumoniae, and Pseudomonas aeruginosa. All of the natural preparations exerted different levels of antibacterial activity except for bitter melon. These findings shed tremendous light on the up-till-now promising effect of the natural antibiotics arsenal and necessitate the importance of systemically studying their individual and synergistic mechanisms, interactions, and kinetics.

In Vitro Antimicrobial Activity and Aggregation Abilities of Probiotic Lactobacillus casei and Lactobacillus salivarius Against Oral Pathogens

The antagonistic effect of probiotics against oral pathogens merits exploration because these bacteria are beneficial to the host’s health. The antimicrobial activity of two probiotic strains, Lactobacillus casei and Lactobacillus salivarius, as well as L. casei and L. salivarius combination (1:1), was investigated against Streptococcus mutans, Streptococcus sobrinus, Candida albicans, Candida glabrata and Candida tropicalis using agar-well diffusion, auto-aggregation and coaggregation assays. L. salivarius cell-free supernatant (CFS) alone exhibited greater inhibitory effect against Streptococci spp. compared to L. casei CFS alone and the combination. However, no inhibition was observed for Candida spp. L. salivarius alone exhibited significantly stronger auto-aggregation than L. casei alone (p ≤ 0.05) and L. casei and L. salivarius combination. L. salivarius exhibited strong coaggregation ability with Candida spp., followed by Streptococci spp. while L. casei exhibited coaggregation only with Streptococci spp. However, L. casei and L. salivarius combination did not display any coaggregation with all strains. L. salivarius alone exhibited a stronger antagonistic effect on the tested organisms than L. casei alone or in combination. Based on the results, both probiotic strains showed good antimicrobial activities against oral pathogens and should be further studied for their human health benefits.

Sequential microwave-ultrasound-assisted silver nanoparticles synthesis: A swift approach, their antioxidant, antimicrobial, and in-silico studies

The present research work unravels the novel optimization of microwave-ultrasound-assisted rapid synthesis of Olea europaea capped silver nanoparticles (O-AgNps) as a capping and stabilizing agent that is not previously studied. The synthesized O-AgNps were characterized using UV–Visible spectroscopy, Fourier transform infrared spectroscopy (ATR-FTIR), proton nuclear magnetic resonance (1H NMR), dynamic light scattering-zeta potential (DLS-Zeta potential), high-resolution transmission electron microscopy-energy dispersive X-ray spectroscopy (HR-TEM-EDAX), and atomic force microscopy (AFM) techniques. The HR-TEM-EDAX revealed that O-AgNps were ∼ 10 nm in diameter with a polydispersity index of 0.191 and were spherical to elliptical. The nanoparticles were analysed for the in-vitro 2,2-diphenyl-1-picrylhydrazyl (DPPH) antioxidant, agar-well diffusion antibacterial assay, minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) assays. The results were promising with a half-maximal inhibitory concentration (IC50) of 155.08 µg/mL for the antioxidant assay. The antimicrobial agar-well diffusion assay showed maximum zones of 24.9 ± 0.14 mm diameters at 8 mg/mL for Staphylococcus aureus (S. aureus) and 24.5 ± 0.7 mm at 8 mg/mL for Escherichia coli (E. coli). The MICs and MBCs were 156.25 µg/mL and 625 µg/mL for the antimicrobial assays againstS. aureusandE. coli. Additionally, the research throws limelight on the in-silico molecular docking analysis using AutoDock Vina software and arrives at a possible elucidation to support the experimental work.

In Vitro and In Vivo Evaluation of Lacticaseibacillus rhamnosus GG and Bifidobacterium lactis Bb12 Against Avian Pathogenic Escherichia coli and Identification of Novel Probiotic-Derived Bioactive Peptides.

Avian pathogenic E. coli (APEC), an extra-intestinal pathogenic E. coli (ExPEC), causes colibacillosis in poultry and is also a potential foodborne zoonotic pathogen. Currently, APEC infections in poultry are controlled by antibiotic medication; however, the emergence of multi-drug-resistant APEC strains and increased restrictions on the use of antibiotics in food-producing animals necessitate the development of new antibiotic alternative therapies. Here, we tested the anti-APEC activity of multiple commensal and probiotic bacteria in an agar-well diffusion assay and identified Lacticaseibacillus rhamnosus GG and Bifidobacterium lactis Bb12 producing strong zone of inhibition against APEC. In co-culture assay, L. rhamnosus GG and B. lactis Bb12 completely inhibited the APEC growth by 24h. Further investigation revealed that antibacterial product(s) in the culture supernatants of L. rhamnosus GG and B. lactis Bb12 were responsible for the anti-APEC activity. The analysis of culture supernatants using LC-MS/MS identified multiple novel bioactive peptides (VQAAQAGDTKPIEV, AFDNTDTSLDSTFKSA, VTDTSGKAGTTKISNV, and AESSDTNLVNAKAA) in addition to the production of lactic acid. The oral administration (108CFU/chicken) of L. rhamnosus GG significantly (P < 0.001) reduced the colonization (~ 1.6 logs) of APEC in the cecum of chickens. Cecal microbiota analysis revealed that L. rhamnosus GG moderated the APEC-induced alterations of the microbial community in the cecum of chickens. Further, L. rhamnosus GG decreased (P < 0.05) the abundance of phylum Proteobacteria, particularly those belonging to Enterobacteriaceae (Escherichia-Shigella) family. These studies indicate that L. rhamnosus GG is a promising probiotic to control APEC infections in chickens. Further studies are needed to optimize the delivery of L. rhamnosus GG in feed or water and in conditions simulating the field to facilitate its development for commercial applications.

The Efficacy of Moina micrura Enriched with Probiotic Bacillus pocheonensis in Enhancing Survival and Disease Resistance of Red Hybrid Tilapia (Oreochromis spp.) Larvae.

The administration of probiotics via live feeds, such as Artemia and rotifers, has gained significant attention. Moreover, indiscriminate use of antibiotics in conventional aquaculture practices in order to prevent or control disease outbreaks has resulted in the occurrence of residues and antimicrobial resistance. Thus, the application of eco-friendly feed additives, such as probiotics, as a safer alternative has received increasing attention in recent years. However, only minimal information on the administration of probiotics via freshwater cladoceran Moina micrura is available despite being commonly used for larval and post-larval feeding of freshwater crustaceans and fish. Thus, this study aimed to evaluate the application of Bacillus pocheonensis strain S2 administered via M. micrura to red hybrid tilapia (Oreochromis spp.) larvae. Bacillus pocheonensis that has been previously isolated from Spirulina sp. was subjected to preliminary in vitro evaluation of antagonistic properties. The agar well-diffusion assay revealed that this probiont could inhibit the growth of Streptococcus agalactiae and Aeromonas hydrophila. The size of inhibition zones ranged from 8.8 ± 0.2 to 18.2 ± 0.4 mm. Moina micrura was later used as a biological model in preliminary in vivo bacterial challenge assays to evaluate the efficacy of B. pocheonensis in protecting the host from diseases. Moina micrura was pre-enriched with B. pocheonensis at and before S. agalactiae and A. hydrophila were introduced into the culture. The study revealed that B. pocheonensis at was able to significantly enhance the survival of M. micrura after being challenged with both pathogens (63 ± 3%) in comparison to the control group. The relative percentage survival (RPS) of M. micrura was highest (p < 0.05) when treated with B. pocheonensis at both concentrations and (38.33) after being challenged against S. agalactiae. To assess the efficacy of B. pocheonensis in protecting red hybrid tilapia against streptococcosis, the larvae were fed with either unenriched (control) Moina or probiont-enriched Moina daily for 10 days. A significantly (p < 0.05) higher survival rate (77 ± 3%) was observed in larvae fed with probiont-enriched M. micrura compared to other treatments, and the RPS was recorded at 62.90. In addition, the S. agalactiae load was suppressed in larvae fed probiont-enriched M. micrura () in comparison to the control group (), indicating that the probiont might have contributed to the improvement of tilapia health and survival. This study illustrated that M. micrura was suitable to be used as a vector for probiotics in freshwater fish larvae as an alternative to hazardous antibiotics for disease control.

Honey: Determination of volatile compounds, antioxidant and antibacterial activities

Honey is an important functional food for human health and nutrition that is collected by honey bees and stored in the honeycombs. In this study, total phenolic content, antioxidant activity and volatile compounds of 13 different honey samples collected from various districts of Malatya province were investigated. As a result of this study, it was determined that the total phenolic content varied between 8.50 mg GAE 100 g&lt;sup&gt;–1&lt;/sup&gt; and 73.90 mg GAE 100 g&lt;sup&gt;–1 &lt;/sup&gt;and it was observed that the honey samples were rich in aldehydes, aliphatic acid and esters, alcohols, hydrocarbons, carboxylic acid esters, ketones, terpenes, fatty acids and esters. In addition, the antibacterial effects of honey samples were determined against 18 different pathogenic bacteria using agar well diffusion (AWD) method, minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). In AWD assay, it was recorded that inhibition zone diameters varied between 9 mm and 14 mm and honey samples were found to have a partial inhibitory effect against selected target pathogens.

Investigation of the Resistance and Sensitivity of Infectious Bacteria to Dendrostellera lessertii and Chemical Composition Analysis

Introduction: Herbal plants are important sources for finding new and rare products of medicinal value for drug development. The present research aimed to investigate the antibacterial properties of Dendrostellera lessertii against infectious bacteria and analyze its chemical composition. Methods: The different organs comprising root, stem, and leaf of D. lessertii from Lorestan province, Iran, were tested. Antibacterial activity was assessed using the agar well-diffusion assay. The total phenolic content (TPC) and total flavonoid content (TFC) were assessed by the Folin Ciocalteu and aluminum chloride methods, respectively. Minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were tested by the serial dilution method, and chemical compositions were analyzed by gas chromatography-mass spectrometry (GC/MS). Results: The chemical composition analysis showed the dominance of bergamotol (10.62%) and bis (2-ethylhexyl) phthalate (7.49%) in the stem extract. However, phytol (12.64%) and E-11-hexadecenal (12.53%) were major constituents in the root extract. Furthermore, major constituents in the leaf extract were phytol (19.658%) and hexadecanoic acid (7.151%). The methanolic extract of root exhibited the highest TPC as 109.1±2.2 mgGA/g and TFC as 2.1±0.33 mgQ/g. The root methanolic extract demonstrated a MIC of 3.125 mg/mL against Enterococcus faecalis. Accordingly, the highest sensitivity and resistance were observed on E. faecalis and Pseudomonas aeruginosa, respectively. Conclusion: Dendrostellera lessertii extract is suggested as a source for antimicrobial drugs, especially to treat bacterial infections.

Antimicrobial Activity of Sorghum Phenolic Extract on Bovine Foodborne and Mastitis-Causing Pathogens.

Antimicrobial resistance in bacterial pathogens associated with bovine mastitis and human foodborne illnesses from contaminated food and water have an impact on animal and human health. Phenolic compounds have antimicrobial properties and some specialty sorghum grains are high in phenolic compounds, and the grain extract may have the potential as a natural antimicrobial alternative. The study’s objective was to determine antimicrobial effects of sorghum phenolic extract on bacterial pathogens that cause bovine mastitis and human foodborne illnesses. Bacterial pathogens tested included Escherichia coli, Salmonella Typhimurium, Campylobacter jejuni, Campylobacter coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Klebsiella oxytoca, Staphylococcus aureus, and Enterococcus faecalis. Antibacterial activities of sorghum phenolic extracts were determined by agar-well diffusion assay. Sorghum phenolic extract was added to the wells in concentrations of 0, 100, 200, 500, 1000, or 4000 µg/mL. The control wells did not receive phenolic extract. Plates were incubated for 18–24 h, and the diameter of each zone of inhibition was measured. The results indicated that sorghum phenolic extract had inhibitory effects on Staphylococcus aureus, Enterococcus faecalis, Campylobacter jejuni, and Campylobacter coli.

In vitro Evaluationof the Antimi- crobial Activity of a Topical Skin Preparation Containing 0.1% Polyhexanide vs a Topical Skin Prepa-ration Containing 1% Silver Sulfadiazine

Aim: The effective in vitro antibacterial activity on Staphylococcus aureus (S.aureus), Pseudomonas aeruginosa (P.aeruginosa), Klebsiella pneumoniae (K.pneumoniae),Escherichia coli (E.Coli) and the combination of S.aureus and K. pneumonia of a topical cream based on 0.1% polyhexanidewas compared to a topical cream based on 1% silver sulfadiazine.A topical cream containing 0,1% gentamicin was used as a positive control and a white blank topical cream was used as negative control. Materials and Methods: The in vitro antibacterial activities were determined by agar well-diffusion assay. Two-way Analysis of Variance (ANOVA) was used to test, by calculation of P-values, for significant antiseptic activity in bacteria treated with 0.1% polyhexanide topical cream compared to 1% silver sulfadiazine and to the negative and positive controls. Results: Among the derivatives tested, all the active topical creams analyzed were able to reduce microbial strains. The topical cream based on 0.1% polyhexanide showed a significantly higher antibacterial efficacy in comparison to the topical cream based on 1% silver sulfadiazine on S. aureus and K. pneumonia and on the combination of S. aureus and K. pneumoniae,while no significant difference was detected between the antibacterial activity of the two topical creams against P. aeruginosa and E. coli. Conclusion: These results provide a further insight into the antibacterial activity of polyhexanide and its non-inferiority compared to silver sulfadiazine towards certain bacterial strains (P. aeruginosa and E. coli) and superiority towards other (S. aureus and K. pneumoniae)and support the use of 0.1% Polyhexanide topical preparation for the treatment of wounds that are infected or at risk of infection.

Docking and Antibacterial Activity of Novel Nontoxic 5-Arylidenepyrimidine-Triones as Inhibitors of NDM-1 and MetAP-1

Background: Antibiotic resistance, which occurs through the action of metallo-β-lactamases (NDM-1), is a serious problem in the treatment of infectious diseases. Therefore, the discovery of new NDM-1 inhibitors and promising antibacterial agents as inhibitors of alternative targets (MetAP-1) is important. Method & results: In this study, a virtual library of 5-arylidene barbituric acids was created and molecular docking was performed for identification of novel possible inhibitors of NDM-1 and MetAP-1. Antibacterial activity (agar well-diffusion assay) and cytotoxicity (alamarBlue assay) of perspective compounds were evaluated. Pharmacokinetic profiles and molecular properties were predicted. Conclusion: We have identified possible novel inhibitors of NDM-1 and MetAP-1 with bacteriostatic activity, most of which are not cytotoxic and have potential excellent drug-likeness properties.

Unravelling the beehive air volatiles profile as analysed via solid-phase microextraction (SPME) and chemometrics

ObjectiveBeehive air therapy is recognized as a potential remedy for treating asthma, bronchitis, lung fibrosis, and respiratory tract infections. Developed countries in which beehive air therapy is currently authorized include Germany, Hungary, Slovenia, and Austria. However, scientific proof of its efficacy is lacking which warrants further chemical and biological analyses as a proof of concept. In this study, beehive air volatile profile was determined for the first time along with its individual components (bees, venom, honey, and beeswax). MethodsVolatile compounds were collected from beehive air using solid phase micro-extraction (SPME) coupled to gas chromatography-mass spectrometry (GC–MS). Antimicrobial assay of the air released from 4 beehive products was further performed against Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, and multi drug-resistant Staphylococcus aureus (MRSA) using the in vitro agar-well diffusion and microtiter plate assays.Results and conclusions: A total of 56 volatile compounds were identified from beehive air, venom, bee insect and wax air including 6 fatty acids, 6 alcohols, 10 aldehydes, 5 esters, 1 ether, 9 hydrocarbons, 1 phenol, 7 ketones, 1 nitrogenous compound and 10 terpenes. The most abundant constituents were short-chain fatty acids (26.32%) while the lowest were the nitrogenous compounds (0.82%). The principal component analysis (PCA) scores plot of the UPLC/MS dataset showed the similarity of the beehive air to the insect bee's aroma profile. With regards to antimicrobial assay, beehive air and venom exerted the strongest antimicrobial activity among the examined bee products against S. aureus, K. pneumoniae, A. baumannii, and MRSA in agar-well diffusion assay but failing to exert an effect using microtiter plate assay as in case of bee venom against the aforementioned bacteria.

The impact of cell-free supernatants of Lactococcus lactis subsp. lactis strains on the tyramine formation of Lactobacillus and Lactiplantibacillus strains isolated from cheese and beer

Tyramine is one of the most toxic biogenic amines and it is produced commonly by lactic acid bacteria in fermented food products. In present study, we investigated the influence of selected nisin-producing Lactococcus lactis subsp. lactis strains and their cell-free supernatants (CFSs) on tyramine production by four Lactobacillus and two Lactiplantibacillus strains isolated from cheese and beer. Firstly, we examined the antimicrobial effect of the CFSs from twelve Lactococcus strains against tested tyramine producers by agar-well diffusion assay. Six Lactococcus strains whose CFSs showed the highest antimicrobial effect on tyramine producers were further studied. Secondly, we investigated the influence of the selected six Lactococcus strains and their respective CFSs on tyramine production by tested Lactobacillus and Lactiplantibacillus strains in MRS broth supplemented with 2 g.L−1 of l-tyrosine. Tyramine production was monitored by HPLC-UV. The tyramine formation of all tested Lactobacillus and Lactiplantibacillus strains was not detected in the presence of Lc. lactis subsp. lactis CCDM 71 and CCDM 702, and their CFSs. Moreover, the remainder of the investigated Lactococcus strains (CCDM 670, CCDM 686, CCDM 689 and CCDM 731) and their CFSs decreased tyramine production significantly (P < 0.05) – even suppressing it completely in some cases – in four of the six tested tyramine producing strains.

Growth Inhibitory Effect of Garlic Powder and Cinnamon Extract on White Colony-Forming Yeast in Kimchi.

White colony-forming yeast (WCFY), also referred to as film forming yeast or spoilage yeast, that appear on the surface of kimchi can deteriorate the sensory properties of kimchi, such as odor and texture. Thus, the aim of this study was to develop a method to inhibit the formation of the white colony in kimchi. First, alterations in kimchi manufacturing and storage conditions, including temperatures, pH, salinity, and anaerobic condition, were investigated to determine if they could inhibit the growth of WCFY (i.e., Kazachstania servazzii, Candida sake, Debaryomyces hansenii, Pichia kudriavzevii, and Hanseniaspora uvarum). Thereafter, the anti yeast activity of freeze-dried garlic powder (FGP) and cinnamon ethanol extract (CEE) was evaluated against WCFY using the agar-well diffusion assay. Following the direct application of FGP and CEE to the surface of the kimchi, the inhibitory effects on white colony were determined. The results showed that WCFY can grow under various manufacturing and storage conditions of kimchi. Regarding the growth inhibitory effect on WCFY, FGP exhibited anti yeast activity against four WCFYs. It did not show anti yeast activity against K. servazzii. However, CEE showed anti yeast activity against K. servazzii. In particular, the mixture of 10% FGP and 1.75% CEE, which was manufactured considering the influence of sensory properties in kimchi, exhibited anti yeast activity against all WCFY. Furthermore, the application of the FGP and CEE mixture supplemented with 0.02% xanthan gum to kimchi to enhance adhesion to the kimchi surface, led to a delay in the formation of a white colony on the surface of the kimchi by an average of 17 d at 10 °C compared to the control group. Collectively, the use of a FGP, CEE, and xanthan gum mixture could be an effective method for the inhibition of white colony formation on the surface of kimchi, extending its shelf life.

Phytochemical Profile and Bioactivity of Industrial Rapeseed Meal Ethanol-Wash Solutes

Rapeseed meal is a by-product of oil producing industry which contains a high amount of protein (37–42%). To prepare protein isolates, suitable for human nutrition, the industrial rapeseed meal is often subjected to a pre-treatment with aqueous ethanol solution. The aim of the study was to investigate the phytochemical profile and bioactivity of the ethanol-wash solutes (EWS) obtained as a waste product of the main process of the protein isolate preparation from industrial rapeseed meal. Proximate composition analysis revealed that total carbohydrates were more than half of the product (60.63%). The content of hydrolysable reducing sugars was 44.13%, while glucose was 7.22%. The total phenols amounted 13.38%. EWS contained 1.63% total flavonoids and 242.05 µmol/g dry weight glucosinolates. The major components, as determined by GC–MS analysis, were sucrose, turanose and melibiose with 22.68%, 4.08% and 3.97% of total ion current (TIC) of polar compounds, respectively; cetyl alcohol (2.45% of TIC) and methyl oleate (2.08% of TIC) representing nonpolar compounds, and sinapic acid (73.71% of TIC) which was the prevailing substance of the phenolic acids identified in the EWS. The 0.2% EWS, prepared in aqueous 70% ethanol solution, exhibited 70.68% scavenging capability of DPPH radicals and 585.11 µmol Fe2+/g EWS (dry weight) reducing capacity. The product demonstrated limited antibacterial but broad antifungal activity which was expressed against Aspergillus niger (ATCC 1015), Aspergillus flavus, Penicillium sp., Rhizopus sp. and Fusarium moniliforme (ATCC 38932) as determined by the agar-well diffusion assay. Overall, EWS exhibited bioactive capacity, which revealed its potential application as a value-added product in the food and nutraceutical industries or agriculture. The broad-spectrum antifungal activity makes the product a prospective agent for food biopreservation or plant bioprotection.

Investigação in vitro da atividade antimicrobiana de Mangifera indica frente às bactérias associadas a lesão por pressão

ABSTRACT: Pressure injury they are chronic wounds where the is bacterial infection common and represent a challenging problem for public health. The aim of this study was investigating the antimicrobial activity of Mangifera indica on bacteria associated by pressure injury. In vitro tests were conducted with crude extract and fractions organics against strains Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 12228), Staphylococcus saprophyticus (ATCC 15305) e Escherichia coli (ATCC 25922) through in agar-well diffusion assay and the minimal inhibitory concentrations (MIC) and minimum bactericidal concentrations (MBC) were determined. The extracts ethanolic was the most active, with diameter of inhibition zones ranging between 19,0 and 22,0 mm against the tested bacterial strains. The CIM varied from 0,04 and 0,29 mg/ml against all the tested microorganism also to the extract ethanolic. The fractions organics hexanic and methanolic showed antimicrobial activity against all the tested microorganisms. Chemical study to extraction and isolation of active compound is recommended to in vitro assays these compounds to investigate the antimicrobial activity. KEYWORDS: Mangifera indica. Pressure injury. Antimicrobial activity.

Antimicrobial assessment of polyphenolic extracts from onion (Allium cepa L.) skin of fifteen cultivars by sonication-assisted extraction method

Onion skin possesses various health benefits due to its phenolic and antimicrobial components. In this study, sonication-assisted extracts of onion skin of differentially coloured cultivars (dark-red, red, pink and white) were investigated for their antimicrobial activity against six pathogenic bacteria. Antimicrobial efficacy of fifteen different coloured extracts was analysed by agar well-diffusion assay with principal component analysis (PCA) for comprehensive investigation. Result showed skin extracts of pink cultivars (cv.) significantly (P ≤ 0.05) effective against pathogenic bacteria followed by red and dark red skin. White skin showed least effect on the growth of bacteria. Skin of cv. ‘Phursungi Local’ (pink) and cv. ‘Hissar-3’ (pink) showed best range of inhibition against Staphylococcus aureus, Klebsiella pnuemoniae, Bacillus cereus and Solmonella typhimurium compared to other. Only white skin extracts of cv. ‘Bhima Shubhra’ and ‘Udaipur Local’ inhibited the growth of Pseudomonas aeruginosa up to 4.0 ± 0.0 mm. Minimum inhibitory concentration (MIC) of the effective extracts was also elucidated in the range between 0.09 – 9.0 mg/mL. Skin extracts of cv. ‘Hissar-2’ (red) and ‘Bhima Shubhra’ (white) showed better inhibition at the concentration of 0.45 and 0.72 mg/mL against Streptococcus agalactiae and Pseudomonas aeruginosa, respectively. As per correlation analysis, positive correlation was obtained between total flavonoids and inhibition rate of all the bacteria while a weak correlation (R2 = 0.3967) was observed against Pseudomonas aeruginosa. The waste skin of the analysed cultivars can be utilised in food and health sector as natural preservative and antimicrobial agent.

Common garlic (Allium sativum L.) has potent Anti-Bacillus anthracis activity

Ethnopharmacological relevanceGastrointestinal anthrax, a disease caused by Bacillus anthracis, remains an important but relatively neglected endemic disease of animals and humans in remote areas of the Indian subcontinent and some parts of Africa. Its initial symptoms include diarrhea and stomachache. In the current study, several common plants indicated for diarrhea, dysentery, stomachache or as stomachic as per traditional knowledge in the Indian subcontinent, i.e., Aegle marmelos (L.) Correa (Bael), Allium cepa L. (Onion), Allium sativum L. (Garlic), Azadirachta indica A. Juss. (Neem), Berberis asiatica Roxb. ex DC. (Daruharidra), Coriandrum sativum L. (Coriander), Curcuma longa L. (Turmeric), Cynodon dactylon (L.) Pers. (Bermuda grass), Mangifera indica L. (Mango), Morus indica L. (Black mulberry), Ocimum tenuiflorum L. (Ocimum sanctum L., Holy Basil), Ocimum gratissimum L. (Ram Tulsi), Psidium guajava L. (Guava), Zingiber officinale Roscoe (Ginger), were evaluated for their anti-Bacillus anthracis property. The usage of Azadirachta indica A. Juss. and Curcuma longa L. by Santals (India), and Allium sp. by biblical people to alleviate anthrax-like symptoms is well documented, but the usage of other plants is traditionally only indicated for different gastrointestinal disturbances/conditions. Aim of the studyEvaluate the above listed commonly available edible plants from the Indian subcontinent that are used in the traditional medicine to treat gastrointestinal diseases including those also indicated for anthrax-like symptoms for the presence of potent anti-B. anthracis activity in a form amenable to use by the general population in the endemic areas. Materials and methodsAqueous extracts made from fourteen plants indicated above were screened for their anti-B. anthracis activity using agar-well diffusion assay (AWDA) and broth microdilution methods. The Aqueous Garlic Extract (AGE) that displayed most potent anti-B. anthracis activity was assessed for its thermostability, stability under pH extremes encountered in the gastrointestinal tract, and potential antagonistic interaction with bile salts as well as the FDA-approved antibiotics used for anthrax control. The bioactive fractions from the AGE were isolated by TLC coupled bioautography followed by their characterization using GC-MS. ResultsGarlic (Allium sativum L.) extract was identified as the most promising candidate with bactericidal activity against B. anthracis. It consistently inhibited the growth of B. anthracis in AWDA and decreased the viable colony-forming unit counts in liquid-broth cultures by 6-logs within 6–12 h. The AGE displayed acceptable thermostability (>80% anti-B. anthracis activity retained on incubation at 50 °C for 12 h) and stability in gastric pH range (2–8). It did not antagonize the activity of FDA-approved antibiotics used for anthrax control. GC-MS analysis of the TLC separated bioactive fractions of AGE indicated the presence of previously unreported constituents such as phthalic acid derivatives, acid esters, phenyl group-containing compounds, steroids etc. ConclusionThe Aqueous Garlic Extract (AGE) displayed potent anti-B. anthracis activity. It was better than that displayed by Azadirachta indica A. Juss. (Neem) and Mangifera indica L., while Curcuma longa L. (Turmeric) did not show any activity under the assay conditions used. Further work should be undertaken to explore the possible application of AGE in preventing anthrax incidences in endemic areas.

Cytotoxicity and antimicrobial activity of Dialium ovoideum thwaites, an endemic plant in Sri Lanka

This study was aimed exploring the cytotoxicity and antimicrobial activity of the leaves D. thwaites is an endemic plant to Sri Lanka. The plant is known for its nutritional and medicinal applications where especially the leaf decoctions are being used to wash skin wounds in indigenous medicine. The brine shrimp lethality assays was performed to evaluate normal toxicity and it gave LC50 value greater than 1000 μg/ mL showing that the plant extracts are non-toxic to the normal cells. The agar-well diffusion assay was performed to assess the antimicrobial activity, and strains of bacteria; E. coli, Staphylococcus aureus, Pseudomonas aeruginosa and Methicillin Resistant Staphylococcus aureus (MRSA) and fungus; Candida albicans were used as test organisms. The results indicated that all the extracts are active against Staphylococcus aureus (Gram Positive) with maximum inhibition shown for methanolic and aqueous extracts. When it was tested against MRSA both aqueous and methanolic extracts gave similar inhibitions. The minimal inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were determined as 6.25 mg/mL and 100 mg/mL respectively with S. aureus whereas no inhibition observed by any of the extract against Gram negative bacteria and Candida albicans. Thus, this study revealed the leaves of D. thwaites possesses strong anti-bacterial activity against S. aureus and MRSA. The results confirmed the efficacy of using D. thwaites as the natural antimicrobial agent and suggested to develop the leaves into value added products to be used in topical applications as antiseptic solutions or ointments.&#x0D; Asian J. Med. Biol. Res. June 2020, 6(2): 316-320