Strong Antimicrobial Activity Research Articles

Bioactive metabolites from endophytes of African club moss- Selaginella kraussiana (Kunze) A. Braun exhibit broad-spectrum pharmaceutical utilities

The search for potent natural compounds from plant and microbial sources is increasing logarithmically to combat various types of health issues of which multidrug-resistant microbes and problems related to oxidative stress are the prime ones. Novel secondary metabolites from endophytes have always been potent alternatives to contemporary antimicrobials and antioxidants. The present study shows that two potent endophytic fungal isolates Ascochyta medicaginicola SK16 and Phomopsis sp. SK5 synthesises non-proteinaceous, thermostable secondary metabolites with broad-spectrum antimicrobial, antioxidative, and cytotoxic activity. Bioassay-guided fractionation revealed that the Ethyl acetate (EA) extract of the cell-free culture extract (CFCE) of SK5 and SK16 constitutes ten and eleven secondary metabolites of which 2,4, -di tert butyl phenol, aziridine- 1,2-amino ethyl, actinobolin, bactobolin, azulene, menthyl acetate, phenol, p-[2-(methylamino)ethyl], and imidazole components were significant. SK16 exhibited strong antimicrobial activity against seventeen pathogens including Methicillin-resistant Staphylococcus aureus (MRSA), and C. albicans with a minimum microbicidal concentration of 100- 400 µg mL−1. These metabolites disrupt the microbial cell membranes causing lethal leakage of biomacromolecules- nucleic acid, protein, and potassium ions. Enzymes involved in the EMP pathway, TCA cycle, and gluconeogenesis were also blocked. Both the biofilm formation and transition of Candida cells from the yeast-to-hyphal form were inhibited. SK5 metabolites are potent radical scavengers with an IC50 of 34.25 ± 0.87 – 195.21 ± 5.73 µg mL−1 against DPPH, ABTS, FRAP, and H2O2 free radical generators and significantly increased antioxidant parameters in treated peritoneal macrophage cells of male Wistar rats. Also, SK5 metabolites were cytotoxic against breast (T47D), pancreatic (MIA Paca-2), lung (A549) and colon (HCT-116) cancer cells. The present findings suggest that metabolites from endophytes of African club moss hold potent pharmaceutical utilities.

Bio-inspired synthesis of silver nanoparticles usingsalsola imbricataand its application as antibacterial additive in glass ionomer cement.

Nanotechnology has gained immense popularity and observed rapid development due to the remarkable physio-chemical properties of nanoparticles (NPs) and related nanomaterials. The green production of nanoparticles has many benefits over traditional techniques because the current procedures are expensive, time-consuming, and involve harmful substances that limit their applicability. This study aimed to use a novel green source, the Salsola imbricata (SI) plant, which is commonly found in Central Asia and known for its medicinal properties as a reducing and stabilizing agent for the synthesis of AgNPs. The current study also utilized efficient statistical design, the Plackett-Burman Design of Experiment (DOE) method to synthesize the nanoparticles. The characterization of nanoparticles was carried out using UV-Vis spectroscopy, Fourier Transform Infrared Spectroscopy, and scanning electron microscopy (SEM). The Plackett-Burman design results showed that only two out of four factors i.e., AgNO3 concentration and incubation time, were significant for the synthesis of AgNPs. While remaining factors, incubation temperature and plant extract: AgNO3 ratio were non-significant. The SEM analysis result showed that SI-AgNPs had a size of 20-50nm. The SI-AgNPs demonstrated strong antimicrobial activity against oral pathogens such as Streptococcus mutans and Lactobacillus acidophilus, with the highest efficacy observed at a concentration of 2 mg/ml. The addition of SI-AgNPs in glass ionomer cement significantly increased the antimicrobial efficacy of GIC at different concentration (p≤0.000 for 0.2% and 0.1%, p≤0.01 for 0.05% and p≤0.05 for 0.025% respectively). Based on the results of the current study, the plant based AgNPs can be further evaluated in detail as alternate antimicrobial agent either alone or in combination with other antimicrobial agents for different dental applications.

Recent Advances in Amphipathic Peptidomimetics as Antimicrobial Agents to Combat Drug Resistance

The development of antimicrobial drugs with novel structures and clear mechanisms of action that are active against drug-resistant bacteria has become an urgent need of safeguarding human health due to the rise of bacterial drug resistance. The discovery of AMPs and the development of amphipathic peptidomimetics have lay the foundation for novel antimicrobial agents to combat drug resistance due to their overall strong antimicrobial activities and unique membrane-active mechanisms. To break the limitation of AMPs, researchers have invested in great endeavors through various approaches in the past years. This review summarized the recent advances including the development of antibacterial small molecule peptidomimetics and peptide-mimic cationic oligomers/polymers, as well as mechanism-of-action studies. As this exciting interdisciplinary field is continuously expanding and growing, we hope this review will benefit researchers in the rational design of novel antimicrobial peptidomimetics in the future.

A first-in-human clinical study investigating the safety and tolerability of stabilized hypochlorous acid in patients with chronic leg ulcers.

Biofilm infections in chronic wounds are common and pose a significant clinical challenge. This challenge was addressed by developing the SoftOx Biofilm Eradicator (SBE) composed of hypochlorous acid and acetic acid with strong broad-spectrum antimicrobial activity. First-in-human study investigating the safety and tolerability as primary endpoints, wound size effect and antimicrobial efficacy as secondary endpoints of SBE treatment in chronic leg wound patients. The study was divided into two: a randomized, double-blinded, Single Ascending Dose (SAD) phase (n=16 SBE; n=4 placebo), where patients were treated with SBE or saline (placebo) only once, followed by an open label, Multiple Ascending Dose (MAD) phase (n=8), where patients were treated with SBE once-daily or twice-daily over five days. Reporting according to CONSORT guidelines. SBE was safe and well-tolerated in chronic leg wound patients. There were no significant differences in pain during and after treatment with SBE or the placebo. The SBE treatment reduced bioburden in wounds compared to baseline, with 98 % and 49 % median reduction after SBE or placebo treatment, respectively. A dose dependent trend in absolute wound size reduction was observed in the MAD groups with a median (min, max) change of -2.99 (-14.25, -1.5) cm2 in the once-daily and -10.48 (-17.95, -0.38) cm2 in the twice-daily group, respectively. This study demonstrated the safe use of hypochlorous acid-based SBE in chronic leg wounds with promising trends of immediate antimicrobial action and beneficial effect on wound healing.

Antimicrobial Activity, Genetic Relatedness, and Safety Assessment of Potential Probiotic Lactic Acid Bacteria Isolated from a Rearing Tank of Rotifers (Brachionus plicatilis) Used as Live Feed in Fish Larviculture.

Aquaculture is a rapidly expanding agri-food industry that faces substantial economic losses due to infectious disease outbreaks, such as bacterial infections. These outbreaks cause disruptions and high mortalities at various stages of the rearing process, especially in the larval stages. Probiotic bacteria are emerging as promising and sustainable alternative or complementary strategies to vaccination and the use of antibiotics in aquaculture. In this study, potential probiotic candidates for larviculture were isolated from a rotifer-rearing tank used as the first live feed for turbot larvae. Two Lacticaseibacillus paracasei and two Lactiplantibacillus plantarum isolates were selected for further characterization due to their wide and strong antimicrobial activity against several ichthyopathogens, both Gram-positive and Gram-negative. An extensive in vitro safety assessment of these four isolates revealed the absence of harmful traits, such as acquired antimicrobial resistance and other virulence factors (i.e., hemolytic and gelatinase activities, bile salt deconjugation, and mucin degradation, as well as PCR detection of biogenic amine production). Moreover, Enterobacterial Repetitive Intergenic Consensus-PCR (ERIC-PCR) analyses unveiled their genetic relatedness, revealing two divergent clusters within each species. To our knowledge, this work reports for the first time the isolation and characterization of Lactic Acid Bacteria (LAB) with potential use as probiotics in aquaculture from rotifer-rearing tanks, which have the potential to optimize turbot larviculture and to introduce novel microbial management approaches for a sustainable aquaculture.

Lactic Acid Bacteria and Bacillus subtilis as Potential Protective Cultures for Biopreservation in the Food Industry

The use of bacteria and/or their compounds is an alternative to the use of positive-list additives that the food industry is using as a tool to meet consumer demands for more natural, long-shelf-life, and healthy products, in short, to offer clean label foods. The aim of this study is to investigate the suitability of cell-free supernatants (CFSs) from Qualified Presumption of Safety strains as bioprotective cultures. Out of an initial screening panel of about 200 isolates, strains Pediococcus acidilactici CNTA 1059, Lactiplantibacillus plantarum CNTA 600, Levilactobacillus brevis CNTA 1374, and Bacillus subtilis CNTA 517 demonstrated strong antimicrobial activity against, especially, Gram-positive bacteria. The CFSs of these four strains showed minimum inhibitory concentration values between 0.15% and 5% against Listeria monocytogenes and Lentilactobacillus parabuchneri. None of the four selected strains exhibited acquired resistance to target antibiotics, and the non-toxigenicity of all the CFSs was demonstrated. In the case of the three lactic acid bacteria, the presence of bacteriocin-like inhibitory substances was confirmed following the decline in antimicrobial activity due to treatment with proteases. Regarding B. subtilis, biosynthetic gene clusters for different bacteriocin-like substances, including protease-resistant lipoproteins, were found via whole-genome sequencing. In addition, all of the CFSs exhibited stable antimicrobial activity at a wide range of temperatures (70–121 °C) used for the pasteurization and sterilization of food products, with a loss of antimicrobial activity ranging from 3% to 28%. These results point to the possibility that CFSs from these strains could be used in the food industry as a biocontrol tool to develop new products.

In-situ synthesis and binding of silver nanoparticles to dialdehyde and carboxylated cellulose nanofibrils, and active packaging therewith

AbstractThe present work reveals the potential application of dialdehyde and carboxylated nanocellulose for the in-situ reduction of Ag+ and immobilization as silver nanoparticles (AgNPs) on cellulose surfaces. Tollens’ reagent (Ag(NH3)2OH) at concentrations ranging from 5·10–3 to 10–1 M was incorporated in both dialdehyde cellulose (DAC) and dialdehyde-modified TEMPO-oxidized cellulose nanofibers (DA-TOCNFs). The results showed that DA-TOCNFs facilitated faster reduction of Ag+ and effective immobilization of AgNPs on the nanocellulose surface. The resulting suspensions exhibited stability and demonstrated strong antimicrobial activity against Bacillus subtilis when coated on paper surfaces. Importantly, the coated papers did not show significant silver migration to food simulants B (3 vol% acetic acid) and D1 (ethanol/water mixture, 50 vol%), indicating the potential of these suspensions for active food packaging. The advantages of using DA-TOCNFs over DAC were attributed to their higher cationic demand and ζ-potential, resulting in a higher density of binding sites. Moreover, the charged and entangled network of DA-TOCNFs allowed for the individualization of AgNPs, unlike DAC, where some agglomerations were observed. Overall, this study presents an improved single-step process for the synthesis of AgNPs on nanocellulose surfaces, highlighting their potential for safe and high-performance applications in food packaging. Paper sheets coated with nanocellulose/AgNPs suspensions fully inhibited the growth of B. subtilis, at least for one month after coating, and caused damage to their cell membranes. This research provides a one-pot facile route to fabricating hybrid nanocellulose/AgNPs systems, stable in water, and may be used directly as a coating layer for board and paper active packaging with little or even undetectable release of Ag.

Green Synthesis and Antimicrobial Study on Jujube Seed Extract Functionalized Ag Nanoparticles

AbstractGreen synthesis of Ag nanoparticles (AgNPs) by using the plant extract is a very important strategy to gain efficient antimicrobial agents with strong antimicrobial activity and low toxicity. In this study, jujube seed extract (JSE) is utilized to green synthesis of AgNPs by both hydrothermal process and solution‐based approaches. UV–vis absorption spectroscopy and infrared spectroscopy (FTIR) spectra confirm that jujube seed extract functionalized Ag nanoparticles are formed by both approaches and jujube seed extract covered on the surface of Ag nanoparticles. Transmission electron microscopy (TEM) images indicate that the JSE‐AgNPs are spherical with the average diameter of 17.7 and 14.2 nm for the hydrothermal process and solution‐based approaches, respectively. X‐ray diffraction (XRD) results indicate that the JSE‐AgNPs prepared by both approaches have face‐centered cubic crystal structure. The antimicrobial activity test reveals that minimum inhibitory concentrations (MIC) of JSE‐AgNPs by the solution‐based method are 62.5, 125, and 62.5 µg mL−1 against Escherichia coli, Staphylococcus aureus, and Candida albicans, respectively. These results imply that the JSE‐AgNPs have potential to be developed as efficient antimicrobial agents.

Oxidative Stress Response Mechanisms Sustain the Antibacterial and Antioxidant Activity of Quercus ilex.

The development of new natural antibiotics is considered as the heart of several investigations in the nutraceutical field. In this work, leaves of Quercus ilex L. treated by tropospheric ozone (O3) and nitrogen (N) deposition, exhibited a clear antimicrobial efficacy against five multi-drug resistant (MDR) bacterial strains (two gram-positive and three gram-negative). Under controlled conditions, it was studied how simulated N deposition influences the response to O3 and the antibacterial and antioxidant activity, and antioxidant performance. The extraction was performed by ultra-pure acetone using two different steps. A higher antioxidant activity was measured in the presence of interaction between O3 and N treatments on Quercus leaves. At the same time, all organic extracts tested have shown bacteriostatic activity against all the tested strains with a MIC comprised between 9 and 4 micrograms/mL, and a higher antioxidant efficacy shown by spectrophotometric assay. Stronger antimicrobial activity was found in the samples treated with O3, whereas N-treated plants exhibited an intermediate antibacterial performance. This performance is related to the stimulation of the non-enzymatic antioxidant system induced by the oxidative stress, which results in an increase in the production of antimicrobial bioactive compounds.

Νovel Polylactic Acid/Tetraethyl Citrate Self-Healable Active Packaging Films Applied to Pork Fillets' Shelf-Life Extension.

Nowadays, increased food safety and decreased food waste are two of the major global interests. Self-healable active packaging materials are an attractive option to achieve such targets. This property is critical for the hygiene and the consumption appropriateness of the food. Polylactic acid is a very promising polymeric matrix that potentially could replace the widely used low-density polyethylene due to its biobased origin and its easy biodegradable nature. The main drawback of this polymeric matrix is its brittle, fragile nature. On the other hand, tetraethyl citrate is a biobased approved food additive which became an attractive option as a plasticizer for industries seeking alternative materials to replace the traditional petrochemically derived compounds. A novel biobased film exhibiting self-healing behavior suitable for food-active packaging was developed during this study. Polylactic acid's brittleness was reduced drastically by incorporating tetraethyl citrate, and a random cut on the original self-repairing film was fully healed after 120 s. The optimum concentration of tetraethyl citrate in the polylactic acid was around 15% v/w with a water/oxygen barrier close to the relevant of polylactic acid and low migration. According to the EC50 parameter, the antioxidant activity was 300% higher than the relevant of pure polylactic acid, while according to the thiobarbituric acid and heme iron parameters, the film resisted lipid oxidation and deterioration. Finally, the total viable count parameter indicates the strong antimicrobial activity of this sample.

AKTIVITAS ANTIBAKTERI EKSTRAK KAYU SECANG ( Caesalpinia sappan L.) TERHADAP BAKTERI Edwardsiella tarda DAN Edwardsiella ictaluri PATOGEN BUDIDAYA PERIKANAN

The disease caused by pathogenic bacteria is one of the main problems in aquaculture in the Jambi Province. One of the diseases that occurs in cultivated catfish is due to infection by bacteria Edwardsiella tarda and Edwardsiella ictaluri, which cause Edwardsiellosis with a mortality rate above 50%. The antibacterial properties of the sappanwood extract (Caesalpinia sappan, L.) can be used to overcome problems in aquaculture, while reducing the use of antibiotics that can have negative impacts. This research aims to explore the antibacterial potential of sappanwood extract (Caesalpinia sappan, L.), a local plant believed to possess strong antimicrobial activity. The study began with isolating bacteria from catfish that showing symptoms of the disease, identifying the test bacteria, followed by extracting sappanwood using 96% ethanol solvent. Subsequently, the antibacterial activity was tested using the disc diffusion method with extract concentrations of 1%, 5%, and 10%. The research results indicate that sappanwood extract at a concentration of 5% has a very strong ability to inhibit the growth of E. tarda and E. ictaluri bacteria. The inhibition zones produced show significant antibacterial activity equivalent to the antibiotic ciprofloxacin used as a positive control.

Medicinal Properties of Cobalt and Copper Nanoparticles Synthesized Using Limonia acidissima Leaf Extract

Aim: The present investigation was undertaken to synthesize Cobalt and copper nanoparticles (NPs) using Limonia acidissima L. leaf extract and to test their few medicinal properties like antimicrobial antioxidant and anti-diabetic activities. Methodology: Limonia acidissima plant leaves were collected from the vicinity of the College and the study was completed in 11 months. The hot aqueous leaf extract and soxhlet extract using ethyl acetate as solvent were prepared. Phytochemical analysis of the leaf extract showed the presence of Tannins, Flavonoids, Alkaloids and absence of Phenols. The leaf extract was then used to make Cobalt and copper nanoparticles (NPs) using Cobalt acetate and Copper sulphate respectively. Results: The formation of NPs was checked by color change and confirmed with UV–visible spectrophotometry. The typical peaks of Co-NPs were detected in the range of maximum wavelength between 380-520 nm and that for Cu NPs was detected between 260-580 nm. The antimicrobial activity of the synthesized NPs of both metal oxides was then tested against Gram positive and Gram negative bacteria and also against two Candida sps. Cobalt NPs exhibited strong antimicrobial activity against all tested organisms but Copper NPs showed no antimicrobial activity. The both NPs were also tested for antioxidant and anti-diabetic properties. Comparatively the Copper NPs possessed higher antioxidant and anti-diabetic activity than the cobalt nanoparticles. Conclusion: Thus, this underutilized plant from India can be further exploited for more medicinal properties and bring it into pharmaceutical usage.

Potential role of Citrus bergamia flower essential oil against oral pathogens

BackgroundOral bacterial infections are difficult to treat due to emergence of resistance against antibiotic therapy. Essential oils are considered emerging alternate therapy against bacterial infections and biofilms. We investigated Citrus bergemia flower essential oil against oral pathogens.MethodsThe essential oil was analsyed using Gas Chromatography(GC–MS), in silico investigations, antioxidant, antimicrobial, antibiofilm and antiquorum sensing assays.ResultsGas Chromatography analysis confirmed presence of 17 compounds including 1,6-Octadien-3-ol,3,7-dimethyl, 48.17%), l-limonene (22.03%) and p-menth-1-ol, 8-ol (7.31%) as major components. In silico analysis showed compliance of all tested major components with Lipinski’s rule, Bioavailability and antimicrobial activity using PASS (prediction of activity spectrum of substances). Molecular docking with transcriptional regulators 3QP5, 5OE3, 4B2O and 3Q3D revealed strong interaction of all tested compounds except 1,6-Octadien-3-ol,3,7-dimethyl. All tested compounds presented significant inhibition of DPPH (2,2-diphenyl-1-picrylhydrazyl) (IC50 0.65 mg/mL), H2O2 (hydrogen peroxide) (63.5%) and high FRAP (ferrous reducing antioxidant power) value (239.01 µg). In antimicrobial screening a significant activity (MIC 0.125 mg/mL) against Bacillus paramycoides and Bacillus chungangensis was observed. Likewise a strong antibiofilm (52.1 – 69.5%) and anti-QS (quorum sensing) (4–16 mm) activity was recorded in a dose dependent manner.ConclusionIt was therefore concluded that C. bergemia essential oil posess strong antioxidant, antimicrobial and antibiofilm activities against tested oral pathogens.

Chemical Composition and Antimicrobial Activity of Essential Oils and Hydrosols from Oregano, Sage and Pennyroyal against Oral Pathogens

In this study, the chemical composition of essential oils (EOs) extracted from Origanum vulgare ssp. hirtum Lamiaceae, (oregano), Salvia officinalis Lamiaceae (sage), Mentha pulegium Lamiaceae (pennyroyal), and respective hydrosols (HSs) has been investigated by Gas Chromatography–Mass Spectrometry (GC-MS). The antimicrobial activity was assessed against two oral pathogens: Gram-positive bacterium Streptococcus mutans and the fungus Candida albicans by determination of Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal/Fungicidal concentration (MBC/MFC). Three-fold diluted solutions were dispensed into each well of a 96-well microtiter plate and, after incubation, MIC was determined by visual monitoring. The MBC/MFC was determined by transferring a small quantity of sample contained in each replicate well of the microtiter plates to appropriate culture media using a microplate replicator. The EOs of the tested herbs showed antimicrobial properties, especially the EO oil of O. vulgare, which exerted the highest antimicrobial activity. HSs of S. officinalis and M. pulegium exerted no antimicrobial activity, in contrast to oregano HS, which displayed strong antimicrobial activity. In all cases, a higher number of compounds were detected in EOs than in the corresponding HSs. The major compounds of sage EO were detected to be α-thujone (25.1%), 1,8-cineole (15.8%) and β-pinene (10.0%), while the HS was characterized by the presence of 1,8-cineole (32.6%), borneol (22.6%) and α-thujone (22.4%). Pennyroyal EO and HS consists mainly of pulegone (62.1 and 50.6%, respectively). Carvacrol was the major component present in EO (63%) and HS (97.3%) of oregano, probably contributing to the antimicrobial activity. Further research is needed in order to elucidate the antimicrobial mechanisms of specific compounds present in essential oils and hydrosols of Lamiaceae grown in Greece against oral pathogens.

Antimicrobial and Probiotic Potential of Lactobacilli Associated with Traditional Fermented Beverages.

Fermented foods have been recognized as a source of probiotic bacteria which can have a positive effect when administered to humans and animals. Discovering new probiotics in fermented food products poses a global economic and health importance. In this study, we investigated the antimicrobial and probiotic potential of lactobacilli isolated from fermented beverages produced traditionally by ethnic groups in Northeast India. Out of thirty Lactobacilli, fifteen exhibited strong antimicrobial activity against Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter aerogenes with significant anti-biofilm and anti-quorum sensing activity. These isolates also showed characteristics associated with probiotic properties, such as tolerance to low pH and bile salts, survival in the gastric tract, auto-aggregation, and hydrophobicity without exhibiting hemolysis formation or resistance to certain antibiotics. The isolates were identified using gram staining, biochemical tests, and 16S rDNA sequencing. They exhibited probiotic potential, broad-spectrum of antibacterial activity, promising anti-biofilm, anti-quorum sensing activity, non-hemolytic, and tolerance to acidic pH and bile salts. Overall, four specific Lactobacillus isolates, Lactiplantibacillus plantarum BRD3A and Lacticaseibacillus paracasei RB10OW from fermented rice-based beverage, and Lactiplantibacillus plantarum RB30Y and Lacticaseibacillus paracasei MP11A from traditional local curd demonstrated potent antimicrobial and probiotic properties. These findings suggest that these lactobacilli isolates from fermented beverages have the potential to be used as probiotics with therapeutic benefits, highlighting the importance of traditional fermented foods for promoting gut health and infectious disease management.

Antimicrobial Activity and Phytochemical Characterization of Baccharis concava Pers., a Native Plant of the Central Chilean Coast.

Few sclerophyllous plants from the central coast of Chile have been systematically studied. This work describes the phytochemical composition and antimicrobial properties of Baccharis concava Pers. (sin. B. macraei), a shrub found in the first line and near the Pacific coast. B. concava has been traditionally used by indigenous inhabitants of today's central Chile for its medicinal properties. Few reports exist regarding the phytochemistry characterization and biological activities of B. concava. A hydroalcoholic extract of B. concava was prepared from leaves and small branches. Qualitative phytochemical characterization indicated the presence of alkaloids, steroids, terpenoids, flavonoids, phenolic, and tannin compounds. The antimicrobial activity of this extract was assessed in a panel of microorganisms including Gram-positive bacteria, Gram-negative bacteria, and pathogenic yeasts. The extract displayed an important antimicrobial effect against Gram-positive bacteria, Candida albicans, and Cryptococcus neoformans but not against Gram-negatives, for which an intact Lipopolysaccharide is apparently the determinant of resistance to B. concava extracts. The hydroalcoholic extract was then fractionated through a Sephadex LH-20/methanol-ethyl acetate column. Afterward, the fractions were pooled according to a similar pattern visualized by TLC/UV analysis. Fractions obtained by this criterion were assessed for their antimicrobial activity against Staphylococcus aureus. The fraction presenting the most antimicrobial activity was HPLC-ESI-MS/MS, obtaining molecules related to caffeoylquinic acid, dicaffeoylquinic acid, and quercetin, among others. In conclusion, the extracts of B. concava showed strong antimicrobial activity, probably due to the presence of metabolites derived from phenolic acids, such as caffeoylquinic acid, and flavonoids, such as quercetin, which in turn could be responsible for helping with wound healing. In addition, the development of antimicrobial therapies based on the molecules found in B. concava could help to combat infection caused by pathogenic yeasts and Gram-positive bacteria, without affecting the Gram-negative microbiota.

Using Subcritical Water to Obtain Polyphenol-Rich Extracts with Antimicrobial Properties.

The use of green extraction methods that meet the criteria of sustainable and environmentally friendly technologies has been increasing in recent decades due to their many benefits. In this respect, extracts obtained using subcritical water are also gaining increased attention because of their potential antioxidant and antimicrobial properties. Their antimicrobial activity is mainly due to the presence of various polyphenolic compounds. Although the exact mechanism of the antibacterial action of polyphenolic compounds has not yet been fully investigated and described, polyphenols are known to affect the bacterial cell at several cellular levels; among other things, they cause changes and ruptures in the cell membranes of the bacterial cell, affect the inactivation of bacterial enzymes and damage bacterial DNA. The difference in the strength of the antimicrobial activity of the extracts is most likely a result of differences in their lipophilicity and in the number and position of hydroxyl groups and double bonds in the chemical structure of polyphenols. By changing the extraction conditions, especially the temperature, during subcritical water extraction, we affect the solubility of the compounds we want to extract. In general, as the temperature increases, the solubility of polyphenolic compounds also increases, and the reduction of the surface tension of subcritical water at higher temperatures also enables faster dissolution of polyphenolic compounds. Different bacterial strains have different sensitivity to different extracts. However, extracts obtained with subcritical water extraction demonstrate strong antimicrobial activity compared to extracts obtained with conventional methods.

Pseudomonas sp. AMGC1 takes on rice blast: Broad-spectrum antimicrobial activity underpins plant growth and disease tolerance.

A diverse group of gram-negative bacteria called Pseudomonas have been extensively researched for their ability to promote plant growth and suppress pathogens. The aim of the study was to identify the strain AMGC1 as a biocontrol agent against rice blast disease and a plant growth-promoting agent. The activity of AMGC1 against phytopathogens and its plant growth promotion activity were tested in vitro. Molecular identification by 16S rRNA gene sequencing, detection of antifungal antibiotic genes, biochemical characterization and antibiotic resistance testing were performed. Moreover, an in-planta biocontrol experiment with a blast susceptible rice cultivar was conducted to assess the effectiveness in managing the disease. Thin-layer chromatography was used to verify the presence of antifungal compounds. The results showed that AMGC1 had strong antimicrobial activity and multiple plant growth promotion traits. The strain was identified as Pseudomonas sp. and it contained genes for phenazine-1-carboxamide, hydrogen cyanide, and 2-hexyl, 5-propyl resorcinol antifungals. In the in-planta suppression experiment, applying AMGC1 strain two days before pathogen inoculation reduced the disease severity by 28% and disease incidence by 29% compared to control. Applying AMGC1 two days after pathogen inoculation resulted in lower reductions in disease severity (17.10%) and disease incidence (18.5%). Two putative bioactive compounds, phenazine-1-carboxamide and 2-hexyl, 5-propyl resorcinol, were isolated and purified from the AMGC1 growth medium. AMGC1 showed varied carbohydrate utilization patterns and both resistance and susceptibility to different antibiotics. The strain had multiple features that enhance plant growth and resistance against various phytopathogens, making it a potential biocontrol agent for sustainable agriculture.

Recovery of Cembratrien-Diols from Waste Tobacco (Nicotiana tabacum L.) Flowers by Microwave-Assisted Deep Eutectic Solvent Extraction: Optimization, Separation, and In Vitro Bioactivity.

Deep eutectic solvents (DESs) are novel solvents with physicochemical properties similar to those of ionic liquids, and they have attracted extensive attention for the extraction of bioactive compounds from different plant materials in the context of green chemistry and sustainable development. In this study, seven DESs with different polarities were explored as green extraction solvents for cembratrien-diols (CBT-diols) from waste tobacco flowers. The best solvent, DES-3 (choline chloride: lactic acid (1:3)), which outperformed conventional solvents (methanol, ethanol, and ethyl acetate), was selected and further optimized for microwave-assisted DES extraction using the response surface methodology. The maximum yield of CBT-diols (6.23 ± 0.15 mg/g) was achieved using a microwave power of 425 W, microwave time of 32 min, solid/liquid ratio of 20 mg/mL, and microwave temperature of 40 °C. Additionally, the isolated CBT-diols exhibited strong antimicrobial activity against Salmonella, Staphylococcus aureus, Escherichia coli, Bacillus subtilis, and Pseudomonas aeruginosa and antitumor activity in the human liver cancer HepG2 and SMMC-7721 cell lines. This study highlights the feasibility of recovering CBT-diols from tobacco flower waste using DESs and provides opportunities for potential waste management using green technologies.

Chemical composition and biological activities of Pittosporum eriocarpum Royle: an unexplored medicinal plant of Indian himalayan region

In this study, different parts (leaf, bark, and fruit) of Pittosporum eriocarpum were investigated to explore its chemical composition and biological activities. The GC-MS analysis confirmed the presence of fifty-seven, eighty-one, and forty-six compounds in leaf, fruit, and bark extract, respectively. The important identified bioactive compounds include 1,3,4,5-tetrahydroxy-cyclohexanecarboxylic acid (quinic acid), falcarinol, tetradecanoic acid, and isopropyl myristate. Further, four polyphenolic compounds namely p-coumaric, chlorogenic, ferulic acid, and catechin were also identified and quantified in different parts through HPLC-PDA analysis. Of the studied parts of P. eriocapum, leaf extract contains the highest total phenolic, flavonoid, and tannin content, and exhibited potent antioxidant activity in ABTS assay. P. eriocarpum extracts also exhibited strong antimicrobial activity against gram-negative bacteria and showed considerable high protection against free radical-mediated DNA damage. To the best of our knowledge, this is the first detailed study of the chemical composition and biological activities of P. eriocarpum.