In vitro investigation on the antiglycative and carbonyl trapping activities of hydroxytyrosol

Advanced glycation end products (AGEs) are involved in the aging and the development of common chronic diseases. Hydroxytyrosol (HT) and its acetate derivative (HTA) exert a significant inhibitory activity on the formation of fluorescent AGEs in bovine serum albumin glycation model systems induced by methylglyoxal (IC50 value of 0.48 and 0.58 μmol/mL, respectively) and glucose (IC50 2.30 and 2.92 μmol/mL, respectively). Furthermore, HT and HTA showed a relevant carbonyl scavenging capacity toward methylglyoxal and glyoxal, which are the most potent promoters of the glycation in vivo, at molar reaction rates from 0.2 to 10 (carbonyl:phenol). However, carbonyl trapping capacity was significantly more effective against methylglyoxal (IC50 0.19 μmol/mL) than glyoxal (IC50 0.26 μmol/mL). At equimolar concentrations, the ester linkage did not significantly affect the antiglycative activity and carbonyl trapping capacity of the orthodiphenolic ring structure. Results were confirmed with the specific inhibition of the formation of the principal AGEs. Formation of carboxymethyl-lysine, argpyrimidine and carboxyethyl-lysine was significantly reduced by 61.9, 71.4 and 20.9 %, respectively. HT and its esters could be considered for upscaling studies as promising natural strategy against adverse consequences of protein glycation.