Nanoemulsions have small droplet size and are kinetically stable colloidal systems. They have enhanced functional properties in comparison to conventional emulsions. The composition and structure of the nanoemulsions can be controlled for the encapsulation and effective delivery of bioactive lipophilic compounds. Nanoemulsions have potential application in the food industry for the delivery of nutraceuticals, coloring and flavoring agents, and antimicrobials. The nanoemulsion formulations of active ingredients can be used for developing biodegradable coating and packaging films to enhance the quality, functional properties, nutritional value, and shelf life of foods. This review focuses on preparation of food grade nanoemulsions using high-energy methods and low-energy approaches and their characterization for physical properties, stability, and microstructure. The application of nanoemulsion formulations for sustainable food processing and improving the delivery of functional compounds, such as colorants, flavoring agents, nutraceuticals, and preservatives or antimicrobial agents in foods has been discussed.

Quorum sensing is involved in biofilm formation and modulates virulence factor production in pathogenic bacteria. Quorum sensing inhibitors can be used as novel intervention strategies for attenuating bacterial pathogenicity. Berberine is an isoquinoline alkaloid with pharmacological properties. The present study investigated the sub-inhibitory concentrations of berberine for inhibiting biofilm formation and quorum sensing regulated phenotypes in the bacterial pathogens Pseudomonas aeruginosa PA01 and Salmonella enterica serovar Typhimurium. Berberine inhibited quorum sensing regulated violacein production in C. violaceum. It reduced the pigment production in the wild type strain at 1.6 mg mL⁻¹ by 62.67%. In the opportunistic pathogen, P. aeruginosa PA01, at sub-MIC, it showed significant antibiofilm activity in by reducing biomass by 71.70% (p < 0.05). It prevented biofilm formation and inactivated biofilm maturation in bacterial pathogens at the concentration ranging from 0.019 to 1.25 mg mL⁻¹. In silico studies showed that berberine interacted with the quorum sensing signal receptors, LasR and RhlR. Furthermore, its anti-infective properties in S. Typhimurium were studied. At sub-inhibitory concentrations of 0.019 mg mL⁻¹, it reduced biofilm formation in S. Typhimurium by 31.20%. It significantly prevented invasion and adhesion of Salmonella invasion in the colonic cell, HT 29 by 55.37% and 54.68%, respectively. It was capable of reducing in vivo virulence in Caenorhabditis elegans infected with Salmonella at 0.038 mg mL⁻¹ by 65.38%. Our results suggest that berberine, previously recognised for its antimicrobial activity, could find potential application as an anti-biofilm and anti-infective agent based on its quorum sensing inhibitory activity.

In the present study, nanoparticles of gold, iron oxide and zinc oxide (ZnO) were studied for cytotoxicity in the colorectal cancer cell HT 29. The metallic nanoparticles in the range of <50 and <100 nm were screened for anticancer activity by MTT assay. The nanoparticles were tested at concentrations ranging from 0.5 to 50 µg/ml. Zinc oxide exhibited significant anti-cancer activity in comparison to other nanoparticles. It had an IC50 value of 17.12 µg/ml. The mechanism of action was studied by fluorescence microscopy with acridine orange, propidium iodide and DAPI staining techniques. The ROS production of ZnO nanoparticles was determined by DCFH-DA. The ZnO nanoparticles were conjugated with novel hydrophobic peptides and evaluated for anticancer activity. It was observed that the nanoparticles peptide complex showed better cytotoxicity than either peptide or nanoparticle alone. Thus, the ZnO nanoparticles tested in our study has anticancer activity against colon cancer cells. It can also be conjugated with peptides and used for targeting cancer cells with higher efficacy.