The increase in β-lactam-resistant Gram-negative bacteria is a severe recurrent problem in the food industry for both producers and consumers. The development of nanotechnology and nanomaterial applications has transformed many features in food science. The antibacterial activity of zinc oxide nanoparticles (ZnO NPs) and their mechanism of action on β-lactam-resistant Gram-negative food pathogens, such as Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, Serratia marcescens, Klebsiella pneumoniae, and Proteus mirabilis, are investigated in the present paper. The study results demonstrate that ZnO NPs possesses broad-spectrum action against these β-lactamase-producing strains. The minimal inhibitory and minimal bactericidal concentrations vary from 0.04 to 0.08 and 0.12 to 0.24 mg/mL, respectively. The ZnO NPs elevate the level of reactive oxygen species (ROS) and malondialdehyde in the bacterial cells as membrane lipid peroxidation. It has been confirmed from the transmission electron microscopy image of the treated bacterial cells that ZnO NPs diminish the permeable membrane, denature the intracellular proteins, cause DNA damage, and cause membrane leakage. Based on these findings, the action of ZnO NPs has been attributed to the fact that broad-spectrum antibacterial action against β-lactam-resistant Gram-negative food pathogens is mediated by Zn²⁺ ion-induced oxidative stress, actions via lipid peroxidation and membrane damage, subsequently resulting in depletion, leading to β-lactamase enzyme inhibition, intracellular protein inactivation, DNA damage, and eventually cell death. Based on the findings of the present study, ZnO NPs can be recommended as potent broad-spectrum antibacterial agents against β-lactam-resistant Gram-negative pathogenic strains.

Spiropyrrolidine tethered piperidone heterocyclic hybrids were synthesized with complete regio- and stereoselectively in excellent yield via a tandem three-component 1,3-dipolar cycloaddition and subsequent enamine reaction in [bmim]Br. The synthesized compounds were evaluated for their anticancer activity against FaDu hypopharyngeal tumor cells. Interestingly, most compounds displayed cytotoxicities similar to the standard anticancer agent bleomycin, with two of them (5a and 5g) being slightly more active than the reference drug. Synthesized compounds have also been evaluated for their apoptosis-inducing properties in a cancer cell model, finding that treatment with compounds 5a–e led to apoptotic cell death.

Human gut microbes are a profitable tool for the modification of food compounds into biologically active metabolites. The biological properties of catechins have been extensively investigated. However, the bioavailability of catechin in human blood plasma is very low. This study aimed to determine the biotransformed catechin metabolites and their bioactive potentials for modulating the immune response of human peripheral blood mononuclear cells (PBMCs). Biotransformation of catechin was carried out using in-vitro gut microbial biotransformation method, the transformed metabolites were identified and confirmed by gas chromatography-mass spectrometry (GC–MS) and high-performance liquid chromatography-mass spectrometry (HPLC–MS). Present observations confirmed that the catechin was biotransformed into 11 metabolites upon microbial dehydroxylation and C ring cleavage. Further, immunomodulatory potential of catechin metabolites was analyzed in peripheral blood mononuclear cells (PBMCs). We found up-regulation of anti-inflammatory cytokine (IL-4, IL-10) and down-regulation of pro-inflammatory (IL-16, IL-12B) cytokine may be due to Th2 immune response. In conclusion, biotransformed catechin metabolites enhance anti-inflammatory cytokines which is beneficial for overcoming inflammatory disorders.