Comparative esterification of phenylpropanoids versus hydrophenylpropanoids acids catalyzed by lipase in organic solvent media

The esterification of phenylpropanoid and hydrophenylpropanoid acids, catalyzed by candida antarctica lipase B (CAL-B), with several alcohols has demonstrated that the substitution pattern on the aromatic ring has a very significant influence on the reactivity of the carboxyl group due, mainly, to electronic effects, when compared to the unsaturated acids with the hydrogenated acids. It is also clear that in the saturated acids there still remain some unclear effects related to the aromatic substituents. Phenylpropanoid acids are compounds widely present in plants, including many edible vegetable staples. Their biological properties, particularly the antioxidant activity, are well known and depend on the structural characteristics of these compounds (Nenadis et al. 2004). Because of their relative polar properties, important efforts have been made in order to increase their hydrophobicity and therefore produce amphiphilic molecules of industrial value (Figueroa-Espinoza and Villeneuve, 2005). Thus, esters of hydro-p-coumaric (Lee et al. 2003), hydroferulic (Hegazi