Chestnut Burrs as Natural Source of Antimicrobial Bioactive Compounds: A Valorization of Agri-Food Waste

Currently, one-third of global food production, accounting for 1.3 billions tons, goes wasted due to major humanitarian and environmental challenges. In such a scenario, the circular bioeconomy model stands as an innovative solution by promoting sustainable production, utilizing agri-food waste, and converting non-renewable products into valuable resources. Here, the circular bioeconomy concept was applied on a previously obtained chestnut burr extract (agri-food waste) composed of gallic acid, quinic acid, protocatechuic acid, brevifolin carboxylic acid, and ellagic acid to evaluate its antimicrobial activity against four bacterial opportunistic pathogens (Enterococcus faecalis, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli). Our results evidenced a modest but measurable antibacterial activity against Enterococcus faecalis, with a minimum inhibitory concentration (MIC) of 64 μg/mL. In silico studies allowed for identifying the potential molecular target, supporting the underlying antibacterial activity of the active principle and providing useful molecular findings regarding their interaction. In this study, we show a robust and comprehensive in vitro and in silico pipeline aimed at the identification of novel antibacterial scaffolds taking advantage of agri-food waste.