In vitro and in vivo efficacy of methyl oleate and palmitic acid against ESBL producing MDR Escherichia coli and Klebsiella pneumoniae

Effective biocontrol of Botrytis cinerea by antifungal metabolites of Trichoderma reesei T1 for gray mold in postharvest tomato

Botrytis cinerea is a serious fungal pathogen that causes gray mold in postharvest tomatoes, leading to voluminous economic losses during storage and transport. Trichoderma reesei T1 has demonstrated an enormous antagonistic activity against B. cinerea by 69.2 % in a dual culture assay. Both culture filtrates and ethyl acetate extract of T. reesei T1 exhibited strong inhibition on the growth, conidial germination, and germ tube elongation of the pathogen. Di(2-ethylhexyl) phthalate, constituting 74.64 % of the extract, was identified as the main component through GC-MS analysis. Gray mold incidence and severity in tomato fruits treated with the filtrates and extract were significantly reduced at all tested concentrations. For example, the disease severity was 8.6 % at 70 % from the filtrate, and 7.6 % at 10 mg mL-1 from the extract after five days in fruits inoculated with B. cinerea. Furthermore, the content of total phenolic and flavonoid compounds in tomato fruits treated with filtrates and extract of T. reesei was remarkably higher levels compared to the untreated group as well as enhancing antioxidant activity during the whole experiment. The treatment with the filtrates and extract also increased the activities of peroxidase (POD), polyphenoloxidase (PPO), and phenylalanine ammonia-lyase (PAL) in tomato fruits throughout the experiment. In conclusion, both filtrates and extract of T. reesei caused a substantial inhibitory effect on gray mold in postharvest tomato fruits. Thus, T. reesei presents a proper alternative to prevent and control tomato postharvest diseases throughout storage time.

Antibiotic potential and metabolic modulation of Bacillus velezensis VTRNT 01 in response to bacterial elicitors

Bacterial elicitors are recognized for their ecological role in stimulating plant defenses and enhancing the production of beneficial metabolites. This study explores the antibiotic potential of endophytic Bacillus velezensis VTRNT 01, isolated from Adenosma bracteosum Bonati, under co-cultivation with bacterial elicitors (Staphylococcus aureus, Escherichia coli, and Aeromonas hydrophila). By leveraging these interactions, we aim to unlock the full potential of endophytic bacteria for sustainable applications in agriculture and pharmaceuticals. Using gas chromatography-mass spectrometry (GC-MS) analysis, we identified a total of 42 distinct chemical compounds produced under these conditions. Notably, 15 of these compounds were exclusively induced by the elicitor treatment, suggesting a strong interactive effect between Bacillus velezensis and the elicitors. Among the identified compounds, several have well-documented antimicrobial properties, including benzaldehyde, benzeneacetic acid, and tetradecanoic acid, which were shown to exhibit significant antibacterial activity against common pathogens. These findings demonstrate the potential of bio-elicitor strategies to enhance the biosynthesis of antimicrobial compounds, paving the way for innovative solutions in crop protection and the development of new therapeutic agents.

Cymbopogon proximus phytochemicals induce S-phase arrest in A549 lung cancer cell lines via CDK2/cyclin A2 inhibition: gas chromatography-mass spectrometry and molecular docking analyses

Cymbopogon proximus comprises several phytoconstituent classes that are reported to possess anticancer activity; however, studies on the anticancer potentials of the plant are lacking. C. proximus was extracted using solvents with increasing polarity. In-vitro cytotoxic activity of C. proximus extracts was examined against liver (HepG2), lung (A549), prostate (PC3), and bone (MG63) cell lines using MTT assay in comparison to doxorubicin. Flow cytometry was used to analyze the cell cycle for identification of the phase of inhibition. Chemical composition of the most active fraction was examined using the GC/MS technique. Molecular docking was used to explore the mechanism of cytotoxicity against A549, and the results were confirmed by Western blot analysis. Petroleum ether fraction was the highly effective fraction against A549 with IC50 = 14.02 ± 2.79. GC/MS analysis of Pet.Eth led to the identification of nine compounds in unsaponifiable matter and 27 components in the saponifiable fraction. Di-N-octyl phthalate, 3-β-hydroxylean-11.13(18)-dien-30-oic acid methyl ester, elemol hydrocarbons, linoelaidic acid and linoleic acid demonstrated the lowest docking binding scores and similar binding modes against CDK2 as compared to that attained by the native ligand R-Roscovitine "CDK2 ATP inhibitor". Western blot analysis demonstrated that CDK2/cyclinA2 protein expression has been suppressed in A549 cell lines by Pet.Eth fraction.

Restraining Staphylococcus aureus Virulence Factors and Quorum Sensing through Lactic Acid Bacteria Supernatant Extracts

The escalating prevalence of antibiotic-resistant bacteria poses a grave threat to human health, necessitating the exploration of novel alternatives to conventional antibiotics. This study investigated the impact of extracts derived from the supernatant of four lactic acid bacteria strains on factors contributing to the pathogenicity of three Staphylococcus aureus strains. The study evaluated the influence of lactic acid bacteria supernatant extracts on the growth, biofilm biomass formation, biofilm metabolic activity, and biofilm integrity of the S. aureus strains. Additionally, the impact on virulence factors (hemolysin and coagulase) was examined. Gas chromatography coupled with mass spectrometry was used to identify the bioactive compounds in the extracts, while molecular docking analyses explored potential interactions. Predominantly, the extracts contain eight 2,5-diketopiperazines, which are cyclic forms of peptides. The extracts demonstrated inhibitory effects on biofilm formation, the ability to disrupt mature biofilms, and reduce the biofilm cell metabolic activity of the S. aureus strains. Furthermore, they exhibited the ability to inhibit α-hemolysin production and reduce coagulase activity. An in silico docking analysis reveals promising interactions between 2,5-diketopiperazines and key proteins (SarA and AgrA) in S. aureus, confirming their antivirulence and antibiofilm activities. These findings suggest that 2,5-diketopiperazines could serve as a promising lead compound in the fight against antibiotic-resistant S. aureus.

Hydrolysis of Edible Oils by Fungal Lipases: An Effective Tool to Produce Bioactive Extracts with Antioxidant and Antimicrobial Potential

Hydrolysis of olive, rapeseed, linseed, almond, peanut, grape seed and menhaden oils was performed with commercial lipases of Aspergillus niger, Rhizopus oryzae, Rhizopus niveus, Rhizomucor miehei and Candida rugosa. In chromogenic plate tests, olive, rapeseed, peanut and linseed oils degraded well even after 2 h of incubation, and the R. miehei, A. niger and R. oryzae lipases exhibited the highest overall action against the oils. Gas chromatography analysis of vegetable oils hydrolyzed by R. miehei lipase revealed about 1.1 to 38.4-fold increases in the concentrations of palmitic, stearic, oleic, linoleic and α-linolenic acids after the treatment, depending on the fatty acids and the oil. The major polyunsaturated fatty acids produced by R. miehei lipase treatment from menhaden oil were linoleic, α-linolenic, hexadecanedioic, eicosapentaenoic, docosapentaenoic and docosahexaenoic acids, with yields from 12.02 to 52.85 µg/mL reaction mixture. Folin-Ciocalteu and ferric reducing power assays demonstrated improved antioxidant capacity for most tested oils after the lipase treatment in relation to the concentrations of some fatty acids. Some lipase-treated and untreated samples of oils, at 1.25 mg/mL lipid concentration, inhibited the growth of food-contaminating bacteria. The lipid mixtures obtained can be reliable sources of extractable fatty acids with health benefits.

Antibacterial Activity and Mechanism of Polygonum orientale L. Essential Oil against Pectobacterium carotovorum subsp. carotovorum

Infected by Pectobacterium carotovorum subsp. carotovorum (Pcc), the quality of Chinese cabbage could severely decline. Using chemical bactericides to control Pcc could cause food safety problems. Thus, we investigated the optimum extraction conditions, antibacterial activity, chemical compounds and antibacterial mechanism of Polygonum orientale L. essential oil (POEO) against Pcc in order to search a new way to control Pcc. The optimum extraction conditions of POEO (soaking time 2.6 h, extraction time 7.7 h and ratio of liquid to solid 10.3 mL/g) were optimized by response surface methodology. The minimum inhibitory concentration (MIC) of POEO against Pcc was 0.625 mg/mL. The control efficiency of protective activity of POEO against Pcc was 74.67~92.67%, and its curative activity was 76.00~93.00%. Then, 29 compounds were obtained by GC-MS; the prime compounds of POEO were phytol, phytone, n-pentacosane, 1-octen-3-ol and β-ionone. It was verified that, compared with control samples, POEO destroyed cell morphology. It increased surface potential, increased hydrophobicity, damaged cell walls, destroyed the integrity and permeability of cell membrane, reduced membrane potential (MP), and changed membrane protein conformation. It inhibited the activities of pyruvate kinase (PK), succinate dehydrogenase (SDH) and adenosine triphosphatase (ATPase). Briefly, the results of this study demonstrate that POEO showed effective inhibitory activity against Pcc, thus POEO could have potential application in controlling Pcc.