Enzymatic synthesis of fatty acid esters of trehalose: Process optimization, characterization of the esters and evaluation of their bioactivities.

Abstract

One-pot synthesis of caprylic, lauric and palmitic acid mono- and diesters of trehalose was catalyzed by the lipase Fermase CALB™ 10000. An optimized molar conversion of 35% of trehalose to its palmitate esters was obtained in acetone at 60°C with a trehalose:palmitic acid molar ratio of 1:5 in 4h. Trehalose fatty acid esters (THFAE) were purified by column chromatography and characterized using TLC, HPTLC, HR-MS, ATR-FTIR, and differential scanning calorimetry. THFAE were studied for their antimicrobial potential against four bacterial, and two fungal species. Trehalose monolaurate and trehalose dicaprylate demonstrated MIC of 0.45mM and 16mM against Pseudomonas aeruginosa and Escherichia coli, respectively. Trehalose monocaprylate showed the highest inhibition of biofilm forming property against Staphylococcus aureus (86.25%) at 99.2mM and trehalose dipalmitate had lowest IC50 of 13.23mM. Furthermore, their anti-inflammatory property was studied in vitro using 15-LOX inhibition assay and human red blood cell membrane stabilization assay. In the confirmatory in vivo tests using carrageenan-induced rat paw edema assay, inflammation in disease control group reached up to 63% as against 32% and 20% for trehalose dilaurate and diclofenac treated groups, respectively. THFAE can hence find potential applications in pharmaceuticals, functional foods, and nutraceuticals.