Over the past decade, numerous publications have emerged in the literature focusing on the inhibition of quorum sensing (QS) by plant extracts and phenolic compounds. However, there is still a scarcity of studies that delve into the specific mechanisms by which these compounds inhibit QS. Thus, our question is whether phenolic compounds can inhibit QS in a specific or indirect manner and to elucidate the underlying mechanisms involved. This study is focused on the most studied QS system, namely, autoinducer type 1 (AI-1), represented by N-acyl-homoserine lactone (AHL) signals and the AHL-mediated QS responses. Here, we analyzed the recent literature in order to understand how phenolic compounds act at the cellular level, at sub-inhibitory concentrations, and evaluated by which QS inhibition mechanisms they may act. The biotechnological application of QS inhibitors holds promising prospects for the pharmaceutical and food industries, serving as adjunct therapies and in the prevention of biofilms on various surfaces.

The emergence of multidrug-resistant bacteria stimulates the search for new substitutes to traditional antimicrobial agents, especially molecules with antivirulence properties, such as those that interfere with quorum sensing (QS). This study aimed to evaluate the potential of phenolic compounds for QS inhibition in a QS biosensor strain (Chromobacterium violaceum) and three foodborne bacterial species (Aeromonas hydrophila, Salmonella enterica serovar Montevideo, and Serratia marcescens). Initially, an in silico molecular docking study was performed to select the compounds with the greatest potential for QS inhibition, using structural variants of the CviR QS regulator of C. violaceum as target. Curcumin, capsaicin, resveratrol, gallic acid, and phloridizin presented good affinity to at least four CviR structural variants. These phenolic compounds were tested for antimicrobial activity, inhibition of biofilm formation, and anti-QS activity. The antimicrobial activity when combined with kanamycin was also assessed. Curcumin, capsaicin, and resveratrol inhibited up to 50% of violacein production by C. violaceum. Biofilm formation was inhibited by resveratrol up to 80% in A. hydrophila, by capsaicin and curcumin up to 40% in S. Montevideo and by resveratrol and capsaicin up to 60% in S. marcescens. Curcumin completely inhibited swarming motility in S. marcescens. Additionally, curcumin and resveratrol increased the sensitivity of the tested bacteria to kanamycin. These results indicate that curcumin and resveratrol at concentrations as low as 6μM are potential quorum sensing inhibitors besides having antimicrobial properties at higher concentrations, encouraging applications in the food and pharmaceutical industries.

Kombucha is an ancient, fermented beverage that has gained increasing popularity worldwide due to its potential health benefits. Its origins trace back to China, from where it spread across Asia and Europe before reaching the modern global market. The fermentation of kombucha is mediated by a Symbiotic Culture of Bacteria and Yeasts (SCOBY), comprising yeasts, acetic acid bacteria, and lactic acid bacteria. The microbial consortium plays a crucial role in the production of organic acids and bioactive metabolites, shaping the sensory characteristics of the beverage. Given the growing interest in kombucha as a functional beverage, this study aims to explore its historical background, fermentation process, and microbiological composition, including key yeasts, acid acetic bacteria, and lactic acid bacteria and their interactions. Additionally, we describe the potential health effects of kombucha, particularly its antimicrobial and antioxidant activity, the probiotic potential of the strains associated with kombucha, and safety considerations while also addressing the risks associated with its consumption. Although several studies suggested that kombucha may have antioxidants, antimicrobial, and probiotic properties, as well as contribute to gut microbiota regulation and immune system support, there is significant variability in the composition of the beverage, especially in artisanal preparations. This variability poses challenges in standardizing its potential effects and ensuring consistent safety. The risk of contamination further underscores the importance of adhering to strict sanitary production standards. To scientifically validate its health benefits and guarantee safe consumption, further research with larger sample sizes and robust methodologies is essential. The findings of this study will contribute to a deeper understanding of the functional properties of kombucha and provide scientific support for its safe and beneficial applications.

Edible coatings have several advantages in preserving foods, such as avoiding water loss, controlling microbial growth, and reducing the need for preservatives added directly to the product. Antimicrobial action can be obtained by adding antimicrobial substances including phenolic compounds commonly found in plant extracts. This study evaluated the phenolic compounds content, antioxidant and antimicrobial activity of pulp, and seed extracts of Mimusopsis comersonii (popularly known in Brazil as abrico), besides the phenolic compounds were identified and quantified in the pulp extract. Edible coatings were incorporated with pulp extract in order to evaluate the preservation of minimally processed apples and baroa potatoes against foodborne bacteria, and enzymatic browning was also determined. Myricetin‐3‐glucoside, quercetin‐3‐glucoside, and kaempferol‐3‐glucoside were identified as major flavonoids in the apricot pulp extract. The seed and pulp extracts inhibited all tested microorganisms, especially Staphylococcus aureus and Salmonella Typhimurium. Edible coatings added with 9% of phenolic extract showed in vitro antimicrobial activity, in addition to being effective in preventing enzymatic browning in minimally processed apples and baroa potatoes for up to 15 days of storage. They were also effective in reducing up to 2 log CFU/g of aerobic mesophiles after 15 days of storage for apples, even though no microbial inhibition in baroa potatoes was observed under the same conditions. The addition of pulp phenolic extract in edible coatings proved to be an alternative in the preservation of apples and in the antibrowning activity of minimally processed baroa potatoes.