Ultrasound-Assisted Synthesis of Antimicrobial Inulin and Sucrose Esters with 10-Undecylenic Acid

Abstract

An environmentally friendly and sustainable ultrasound-assisted esterification of long-chained inulin and sucrose with monounsaturated 10-undecylenic acid was performed. The obtained esters were characterized by thin-layer chromatography (TLC), Fourier transforms infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR) spectroscopy. The spectral analyses demonstrated the successful incorporation of the hydrophobic 10-undecylenoyl residue in the water-soluble carbohydrate backbone. Additionally, the antimicrobial potential of 10-undecylenic esters of inulin and sucrose were tested against nine microorganisms (Gram-positive and Gram-negative bacteria, yeasts, and fungi). Both esters inulin 10-undecylenate and sucrose 10-undecylenate (1 mg/ml) inhibited Bacillus subtilis ATCC 6633, Listeria monocytogenes ATCC 8632, Staphylococus aureus 745, Escherichia coli 3398, yeast Candida albicans 8673, and fungi Penicillium sp. Only inulin 10-undecylenate demonstrated antimicrobial activity against Salmonella typhy 745. Both esters were inactive against fungi Aspergillus niger. The current research demonstrated a new antimicrobial activity of inulin esters. Moreover, the use of “eco-friendly” synthesized inulin and sucrose esters with 10-undecylenic acid as antimicrobial substances with future applications in pharmaceutical and cosmetic products were demonstrated.