Synthesis, Pass Predication of Antimicrobial Activity and Pharmacokinetic Properties of Hexanoyl Galactopyranosides and Experimental Evaluation of their Action against Four Human Pathogenic Bacteria and Four Fungal Strains

Direct unimolar hexanoylation of methyl α-D-galactopyranoside (MDG) at low temperature gave 6-O-hexanoate in 53% yield indicating regioselectivity at the C-6 position. To develop galctopyranoside-based potential antimicrobial sugar esters (SEs), 6-O-hexanoate was further converted into seven new 2,3,4-tri-O-acyl esters in reasonably good yields. Prediction of Activity Spectra for Substances (PASS) and in vitro antimicrobial studies established these SEs as better antifungal agents as compared to antibacterials. ADMET properties reveal that these SEs can penetrate through the blood-brain barrier, they are P-glycoprotein inhibitors, noncarcinogenic, and possess lower median lethal dose (LD50) values. Drug likeliness calculations indicate that these MDG esters are in good agreement with several important parameters. Structure-activity relationship (SAR) of these SEs indicated that the incorporation of hexanoyl and octanoyl group(s) increased the antimicrobial potential of MDG.