SYNTHESIS AND EVALUATION OF SUGAR-BASED ALIPHATIC AND AROMATIC FATTY ACID ESTERS AS ANTIMICROBIAL AND ANTIBIOFILM AGENTS

Food pathogens are responsible of significant economic losses in food industry each year and cause various human diseases.1 Indeed, a recent study by the Centers for Disease Control and Prevention estimated new cases of food-related illness in the United States at around 50 million, resulting approximately in 3,000 deaths and 130,000 hospitalizations every year.2 Some of the common disinfection practices in food industry, such as chemical-based and irradiation, are very effective. However, they are frequently expensive, dangerous and risky for the human health and the environment. In addition, these approaches may have no effect against bacteria organized in biofilm, a wellknown tridimensional structure that confers to bacteria more resistance to environmental stresses as well as to antimicrobial treatments. Other practices, such as the use of common food preservatives (e.g. maleic acid or potassium sorbate), are now proving to be unsafe and toxic. Recently, the use of natural products in combating foodborne bacterial and fungal pathogens has become a trend. However, the antimicrobial activities of most natural products are too low to enable their practical use. In short, there is still a great need for effective antimicrobial food additives that are generally regarded as safe (GRAS) by Food and Drug Administration. In this contest and as a part of our research interests,3-5 we report enzymatic and chemical synthetic procedures applied to obtain sugar-fatty acid esters, and based on the esterification of three different sugars (monosaccharides glucose and mannose, and disaccharide lactose) with aliphatic (C8-C16 saturated fatty acids) or aromatic (phenylacetic, biphenylacetic, triphenylacetic and p-phenylbenzoic) acids. These compounds have been characterized and tested in order to determine their minimum inhibitory concentration (MIC) values against different Gram-positive and Gram-negative bacteria and fungi. Secondarily, the most promising compounds of the series were also tested to evaluate both their antibiofilm activity at different time of development (24 and 48 h, 5 days) of representative food-borne pathogens and biocompatibility profile. The obtained data reveals an elevated percentage of biofilm formation inhibition up to 5 days (> 90% in some cases) and at MICs values no toxicity on Caco-2 cell line. Overall, the analyzed sugar-based surfactants could be considered possible biocompatible and safe preservatives for food and other industrial applications.