Synthesis, Antifungal Activity, and Molecular Docking Studies of Some New Di-O-Isopentanoyl Glucopyranosides

Extensive research in the past decades indicated that the sugar ester (SE) type biomolecules bring long-chain fatty acids with sugar moieties into the plant cells, and play various important roles in food, surfactants, innovative green materials, and biological properties. Thus, methyl α-D-glucopyranoside (4) upon dimolar isopentanoylation furnished the methyl 2,6-di-O-isopentanoyl-α-D-glucopyranoside (5) indicating selectivity at C-2 and C-6 positions. Compound 5 was further acylated and obtained 3,4-di-O-acyl esters 5-8 in good yields. In vitro antifungal activities of these compounds exhibited moderate to good zone of inhibition. To rationalize these results molecular docking studies of 4-8 are performed against lanosterol 14-α-demethylase (CYP 51). Attachment of acyl ester chain(s) in the glucopyranoside ring added more lipophilicity and affected their fungal inhibition via binding with lanosterol 14-α-demethylase enzyme. Especially, isopentanoyl group(s) with lauroyl group(s) as in 8 showed better binding affinity than that of fluconazole indicating the better efficiency of SEs.