Synthesis of lipophilic tyrosyl esters derivatives and assessment of their antimicrobial and antileishmania activities

A large series of tyrosyl esters (TyC2 to TyC18:1) with increasing lipophilicity was synthesized in a good yield using lipase from Candida antarctica (Novozyme 435). Spectroscopic analyses of purified esters showed that the tyrosol was esterified on the primary hydroxyl group. Synthetized compounds were evaluated for either their antimicrobial activity, by both diffusion well and minimal inhibition concentration (MIC) methods, or their antileishmanial activity against Leishmania major and Leishmania infantum parasite species.Among all the tested compounds, our results showed that only TyC8, TyC10 and TyC12 exhibited antibacterial and antileishmanial activities. When MIC and IC50 values were plotted against the acyl chain length of each tyrosyl derivative, TyC10 showed a parabolic shape with a minimum value. This nonlinear dependency with the increase of the chain length indicates that biological activities are probably associated to the surfactant effectiveness of lipophilic derivatives.These results open up potential applications to use medium tyrosyl derivatives surfactants, antioxidants, antimicrobial and antileishmanial compounds in cosmetic, food and pharmaceutical industries.Polyphenolic compounds produced by plants are of considerable interest, both as functional food ingredients and as nutraceuticals [1]. In addition to their antioxidant properties, several studies showed that phenolic compounds also have antimicrobial properties by denaturing proteins and inactivating enzymes [2,3]. Tyrosol [2-(4-hydroxyphenyl) ethanol] is a well-known monophenolic antioxidant present in large amount in olive oil and can be extracted from olive mill waste water [4]. Its efficiency was demonstrated in inhibiting the oxidation of cholesterol in LDL and preventing the modification of the apoproteic moiety [5]. Tyrosol has been also effective in inhibiting leukocyte 5-lipooxygenase [6] and protecting the Caco-2 intestinal mucosa cells against the cytostatic and cytotoxic effect