Creating new water-soluble Iso- and n-fatty acid arginate hydrochloride with antimicrobial properties

Typically, short- and long-chain lipids from oils exhibit different antimicrobial activities and therefore have been used in agriculture and aquaculture, biomedical therapeutic and antibacterial fields. However, these fatty acids have limitations in terms of bioactive efficacy, thermostability and aqueous solubility. In this study, water-soluble iso-fatty acid arginate hydrochloride derivatives with antimicrobial properties were produced by introducing branched (iso-) chain and other linear- (n-) chain fatty acids to the “arginine” amino acid molecule. The two-step synthetic route was straightforward and provided an efficient 88% and 76% product yields for ethyl n-oleoyl arginate hydrochloride and ethyl iso-oleoyl arginate hydrochloride, respectively. ATR-FT-IR, NMR, and LC-MS-Q-TOF techniques were used to thoroughly characterize and confirm the products. These arginate products had strong antimicrobial activities against Listeria innucua, a Gram-positive bacterium with minimum inhibitory concentrations and minimum bactericidal concentrations ranging from 1.8 µg mL⁻¹ to 29.1 µg mL⁻¹. Therefore, the study demonstrated the development of a novel class of antimicrobial compounds from iso-fatty acids and arginates.