SYNTHESIS AND CHARACTERIZATION OF NOVEL CHOLESTERYL LACTATE BASED FATTY ACID ANALOGS AND THEIR IN VITRO ANTIMICROBIAL ACTIVITY

A series of novel cholesteryl lactate-fatty acid conjugates (4a-i) were prepared by esterification of cholesterol with lactic acid, followed by coupling hydroxyl group of cholesteryl lactate with –COOH group of fatty acids including, saturated fatty acids of varying carbon chain of C₁₀-C₁₈, unsaturated fatty acids like 10-undecenoic, oleic ((9Z)-octadec-9-enoic), ricinoleic ((9Z,12R)-12-hydroxyoctadec-9-enoic) and 11-bromoundecanoic acid. Cholesteryl lactate-fatty acid conjugates were characterized by spectroscopic techniques like FT-IR, 1H-NMR, 13C-NMR, ESI-MS and HRMS. All the synthesized compounds were tested for their antimicrobial activity against a panel of seven bacterial strains like Staphylococcus aureus MTCC 96, Bacillus subtilis MTCC 121, Micrococcus luteus MTCC 2470, Klebsiella planticola MTCC 530, Escherichia coli MTCC 739, Pseudomonas aeruginosa MTCC 2453 and fungal strain like Candida albicans. Among them, the compounds with unsaturation (4f and 4h), and functional groups like bromine and hydroxyl group (4g and 4i) showed good antibacterial activity. But, promising activity was observed against Staphylococcus aureus MTCC 96 strain ranging from 7.8-15.6 µg/ml. These compounds (4f-i) are also exhibited good to moderate antifungal activity against different Candida strains ranging between 7.8-31.2 µg/ml.