Microwave-Assisted Synthesis of Lactose Acetates with Antimicrobial, Cytotoxic, and Antiviral Properties

Abstract

The task of this study was to perform the "green" synthesis of lactose octaacetate through microwave irradiation and to establish their biological activities. Lactose ester was prepared after microwave-assisted esterification of lactose with acetic anhydride (yield 85-90 %). Lactose octaacetate was characterized by a high degree of acetylation (DS 3.2-3.7). The lactose esters' structure was elucidated by infrared spectroscopy and nuclear magnetic resonance spectroscopy. Lactose octaacetate showed better antifungal activities than antibacterial activities. It possessed slight to moderate antifungal activities against Aspergillus niger ATCC 1015, Penicillium sp., Rhizopus sp., Fusarium moniliforme ATCC 38932. Lactose acetates demonstrated low cytotoxicity against three cell lines: Madin-Darby bovine kidney (MDBK) cells, human epithelial type 2 (HEp-2), and Madin-Darby canine kidney (MDCK) cells. This is the first report for antiviral activity of lactose acetates against herpes simplex virus type 1 (HSV-1), influenza virus A/Panama/2007/99/H3N2 - (IAV/H3N2), PV-1 and Coxsackievirus B1. It was found that this compound showed activity with SI = 2.4 only against PV-1, but against HSV-1, IAV/H3N2, and Coxsackievirus B1 was inactive. The current study demonstrated the applications of lactose acetates as antimicrobial and antiviral substances in food, pharmaceutical, agricultural and cosmetic preparations.