Lipase-catalyzed selective esterification of catechin

Abstract

Catechins show strong antioxidant, antitumoral, antiviral, and anti-inflammatory activities. The uses of catechins in food, cosmetic, and pharmaceutical formulations seem very attractive. Unfortunately, solubility and stability of catechins are poor in apolar media, which limits their efficient uses. In order to improve the solubility of catechins in the oil phase and maintain their oxidation resistance, a regioselective enzymatic acylation was investigated. The effects of reaction medium, water content, carbon chain length of acyl donor and other factors on the acylation reaction were studied, catechins were enzymatically esterified with an aliphatic acid (stearic acid) using an immobilized lipase Novozym 435 in n-butanol. The results show that when the ratio between catechins and stearic acid was 1:5, adding molecular sieves 4A after 11 h of reaction and the temperature of 60 °C led to the maximum conversion yield of 60.36%. Studies have shown that catechin stearate has a higher antioxidant activity than vitamin E and dibutyl hydroxytoluene (BHT).