Multidrug-resistant (MDR) Escherichia coli is a major foodborne pathogen posing a critical threat to public health, particularly through the contamination of animal products. The increasing prevalence and virulence of MDR E. coli strains underscore the urgent need for alternative antimicrobial strategies. This study aimed to synthesize and characterize zinc oxide nanoparticles (ZnO-NPs) using Stevia rebaudiana as a sustainable capping and reducing agent, aligning with green chemistry principles. Of the 120 fish samples, 74.2% (89/120) were positive for E. coli contamination. Among the identified E. coli strains, 77.8% (119/153) were classified as MDR. Resistance profiling revealed 22 distinct patterns, and seven highly resistant and virulent strains were selected for further analyses. The eco-friendly auto-combustion synthesis of ZnO-NPs produced nanoparticles with semi-spherical to hexagonal shapes and an average size ranging from 12 to 25 nm. Scanning Electron Microscope–Energy Dispersive X-ray analysis (SEM-EDS) confirms that ZnO-NPs primarily consist of zinc (37.5%) and oxygen (19.9%), with carbon (42.6%) indicating the green synthesis process. ZnO-NPs demonstrated potent, dose-dependent antibacterial and antibiofilm activity against the selected MDR E. coli strains. Additionally, mechanistic studies revealed that ZnO-NPs disrupt bacterial cell membranes, alter cellular morphology, and interfere with DNA integrity. These findings highlight the potential of eco-friendly ZnO-NPs as a promising nanomaterial for enhancing food safety and addressing the growing challenge of MDR foodborne bacteria.

The rise of multidrug-resistant (MDR) bacteria in food products poses a significant threat to public health, necessitating innovative and sustainable antimicrobial solutions. This study investigates the green synthesis of zinc oxide nanoparticles (ZnO-NPs) using Stevia rebaudiana extracts to evaluate their antibacterial and antibiofilm activities against MDR Staphylococcus aureus strains isolated from sold fish samples. The obtained results show that the contamination with S. aureus reached 54.2% in the tested fish samples (n = 120), underscoring the urgent need for effective interventions. ZnO-NPs were successfully synthesized and characterized using UV-visible spectroscopy, FT-IR, XRD, and TEM, confirming their formation with an average size of 15.7 nm and reflecting their suitability for antimicrobial and biological applications. ZnO-NPs exhibited potent antibacterial activity, with a maximum inhibition zone of 24.4 ± 0.4 mm at 20 μg/disk, MIC values of 6.25–25 μg/mL, and MBC values of 12.5–50 μg/mL. Additionally, biofilm formation was inhibited by up to 92.1% at 250 μg/mL. Our mechanistic study confirmed that ZnO-NPs damage bacterial membranes and DNA, leading to the intracellular leakage of cell components that lead to bacterial cell lysis. The use of S. rebaudiana in ZnO-NP synthesis aligns with green chemistry principles, offering an eco-friendly alternative to conventional antibiotics and enhancing the bioactivity of ZnO-NPs, and may address the growing issue of antimicrobial resistance, thereby contributing to improved food safety and public health protection.

This study explored the impact of ethanol as a co-solvent in supercritical fluid extraction on the recovery of bioactive compounds from carrot seeds and assessed the resulting extracts for antimicrobial, α-amylase and α-glucosidase, and butyrylcholinesterase inhibitory potential. Ethanol supplementation significantly improved extraction performance, with the yield increasing from 110 mg in the absence of ethanol to 134 mg at 5% ethanol, followed by a slight decrease to 132 mg at 10%. High-performance liquid chromatography (HPLC) revealed pronounced phytochemical enrichment at 5% ethanol, particularly for chlorogenic acid (1541.24 µg/g), gallic acid (1279.27 µg/g), and hesperetin (1513.68 µg/g), indicating enhanced recovery of phenolic and flavonoid constituents. The 5% ethanol extract demonstrated superior antimicrobial activity, producing inhibition zones of 19 mm against Enterococcus faecalis, 26 mm against Klebsiella pneumoniae, 25 mm against Staphylococcus aureus, and 29 mm against Candida albicans. Values of both minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) were markedly reduced, while antibiofilm activity reached 93.11% for E. faecalis and 91.00% for K. pneumoniae. The extract also exhibited potent inhibitory effects with IC₅₀ values of 7.74 and 13.37 µg/mL, against α-amylase and α-glucosidase, correspondingly, as well as strong butyrylcholinesterase inhibition (IC₅₀ = 2.51 µg/mL), highlighting promising α-amylase/α-glucosidase and butyrylcholinesterase inhibitory potential. Molecular docking further supported these findings, showing that chlorogenic acid bound more strongly than vanillin to OmpK36, lysosomal acid-α-glucosidase, and butyrylcholinesterase, with docking scores ranging from −6.1 to −6.9 kcal/mol. These findings identify ethanol-modified supercritical fluid extraction as a sustainable and effective green strategy for improving the recovery of carrot seed bioactives and enhancing their multifunctional in vitro biological properties. Notably, this study provides the first comprehensive evidence that 5% ethanol modification selectively enriches key phenolic constituents, including chlorogenic acid, gallic acid, and hesperetin, in carrot seed extracts, with corresponding enhancement of α-amylase, α-glucosidase, and butyrylcholinesterase inhibitory activities.

Natural products may address infection, oxidative stress and metabolic disorders. This study used gas chromatography-mass spectrometry (GC-MS), bioassays and molecular docking to characterize Delonix regia seed oil and evaluate its antimicrobial, antibiofilm, radical-scavenging and pancreatic lipase-inhibitory activities. The most abundant tentatively identified peaks in the GC-MS total ion chromatogram were β-sitosterol (26.35%), stigmasterol (14.57%), linoleic acid (10.39%), and oleic acid (5.82%). Minimum inhibitory concentrations (MICs) were 15.62 µg/mL for Listeria monocytogenes, Salmonella typhi, and Candida albicans, and 62.5 µg/mL for methicillin-resistant Staphylococcus aureus. The corresponding inhibition zones were 28 ± 0.7, 21 ± 0.3, 31 ± 0.1, and 15 ± 0.5 mm, respectively. At 75% of the minimum bactericidal/fungicidal concentration, the oil inhibited biofilm formation by 94.95% for both L. monocytogenes and C. albicans. DPPH and ABTS radical-scavenging IC₅₀ values were 17.04 ± 0.25 and 13.17 ± 0.40 µg/mL, respectively, while the pancreatic lipase IC₅₀ was 26.29 ± 0.08 µg/mL. Time-kill assays demonstrated ≥3 log₁₀ CFU/mL reductions, with no recoverable colonies for any of the five tested pathogens within 3 h. Docking predicted stronger stigmasterol binding to L. monocytogenes Sortase A (−6.60 kcal/mol) than to C. albicans lanosterol 14α-demethylase (CYP51; −3.41 kcal/mol), involving hydrogen bonds with Met63 and Arg381, respectively, and hydrophobic contacts. These findings identify a phytosterol-enriched GC-MS-detectable fraction of Delonix regia seed oil with in vitro activities warranting further mechanistic and in vivo investigation.

Background/Objectives: Delonix regia seeds contain phytochemicals with therapeutic potential, but their activity against Helicobacter pylori and biomedical properties remain incompletely characterized. This study aimed to characterize the phenolic and amino acid composition of D. regia seed extract (DRSE) and evaluate its anticancer, wound-healing, anti-inflammatory, anticoagulant, antibacterial, antibiofilm and urease-targeted docking activities. Methods: DRSE was analyzed by high-performance liquid chromatography (HPLC) and amino acid analysis. Biological effects were assessed using MTT cytotoxicity, scratch wound-healing, bovine serum albumin (BSA) denaturation, prothrombin time (PT) and partial thromboplastin time (PTT), antibacterial and crystal violet antibiofilm assays. Gallic acid and vanillin were docked against H. pylori urease (PDB ID: 1E9Y). Results: Gallic acid was the predominant phenolic compound (1417.90 µg/g), while aspartic and glutamic acids dominated the amino acid fraction. DRSE showed preferential cytotoxicity toward A431 carcinoma cells (IC₅₀ = 108.97 ± 0.68 µg/mL) compared with HFB4 fibroblasts (IC₅₀ = 318.56 ± 2.06 µg/mL), yielding a selectivity index of 2.92. Scratch closure was comparable to the control (81.71% versus 80.85%), although the migration rate increased to 16.12 µm. DRSE inhibited protein denaturation by 91.20% (IC₅₀ = 6.39 ± 0.19 µg/mL) and prolonged PT and PTT to 27.37 and 90.50 s, respectively. It inhibited H. pylori with minimum inhibitory and bactericidal concentrations of 31.25 µg/mL and suppressed biofilm formation by 95.39%. Gallic acid and vanillin showed comparable urease docking scores of −4.72 and −4.71 kcal/mol. Conclusions: DRSE showed selective anticancer, anti-H. pylori, antibiofilm, anti-inflammatory, anticoagulant, and moderate pro-migratory activities. Mechanistic, safety and in vivo studies are warranted.