Taking into account that compounds bearing a thiazolyl, pyridyl and indolyl, moieties possess a wide spectrum of biological activities which is related to their capacity to transfer electrons and to scavenge reactive oxygen species (ROS), we synthesized some new heterocyclic aryl acetic acids and the corresponding acetohydroxamic acids and we explored their ability to inhibit soybean lipoxygenase, to present antioxidant and anti-inflammatory activities as well as to present serine proteases inhibition. The compounds were found to strongly inhibit lipid peroxidation and to decrease in vivo the carrageenin induced rat paw edema (28-56%). Compound 1i possesses the highest decrease 56%, in vivo. The tested derivatives presented interesting inhibitory activity on soybean lipoxygenase. Compound 5ii showed significant in vitro inhibition on trypsin (IC(50) 87 microM). The results are discussed in terms of structural and physicochemical characteristics of the compounds. The structures of the synthesized compounds were confirmed by spectral and elemental analysis. Their lipophilicity is experimentally determined by RPTLC method.