Novel Approach for Flavonoid Esters Production: Statistically Optimized Enzymatic Synthesis Using Natural Oils and Application in Cosmetics

The present work describes application of natural triglycerides for lipase-catalyzed esterification of structurally diverse flavonoids-esculin, naringin, and phloridzin. Ester mixtures with laurate, linolenate, or linoleate as prevailing products were obtained in reactions with coconut, linseed, and sunflower oils, respectively. By using response surface methodology, the influences of key experimental factors-reaction time, substrates, and enzyme concentrations-for transesterification of esculin with linseed oil were investigated. High molar conversion (78.5%), product yield (19.13 mg/mL), and specific yield (2.83 mmol/g(enzyme)) were achieved at optimized conditions. Determined optimums were successfully applied in esculin transesterification with other two oils. Furthermore, esculin ester mixtures were incorporated in gel emulsions, and their effect on transepidermal water loss (TEWL) as well as skin sensitivity was examined. Obtained results have shown significant hydration effect and good dermatological compatibility without irritating effects of all examined preparations containing oil-derived esculin esters, making them very prospective for application in skin care products.