Synthesis and Structure/Antioxidant Activity Relationship of Novel Catecholic Antioxidant Structural Analogues to Hydroxytyrosol and Its Lipophilic Esters

Abstract

A large panel of novel catecholic antioxidants and their fatty acid or methyl carbonate esters has been synthesized in satisfactory to good yields through a 2-iodoxybenzoic acid (IBX)-mediated aromatic hydroxylation as the key step. The new catechols are structural analogues of naturally occurring hydroxytyrosol (3,4-DHE). To evaluate structure/activity relationships, the antioxidant properties of all catecholic compounds were evaluated in vitro by ABTS assay and on whole cells by DCF fluorometric assay and compared with that of the corresponding already known hydroxytyrosyl derivatives. Results outline that all of the new catechols show antioxidant capacity in vitro higher than that of the corresponding hydroxytyrosyl derivatives. Less evident positive effects have been detected in whole cells experiments. Cytotoxicity experiments, using MTT assay, on a representative set of compounds evidenced no influence in cell survival.

Effect of hydroxytyrosol methyl carbonate on the thermal, migration and antioxidant properties of PVA‐based films for active food packaging

“…In search of novel hydroxytyrosol‐derived compounds that can be used as AIs in antioxidant food packaging, hydroxytyrosol methyl carbonate (HTyr‐MC) appears a promising candidate due to its strong antioxidant activity, absence of cytotoxicity and water solubility. In consideration of these particular properties, HTyr‐MC was tested as an AI for the PVA matrix in order to obtain novel PVA/HTyr‐MC binary films.…”

Sustainability, Innovation, and Green Chemistry in the Production and Valorization of Phenolic Extracts from Olea europaea L.

“…The selective introduction of the methyl carbonate moiety into HTyr reduces the hydrophilicity, while the free catecholic moiety guarantees the antioxidant activity. In vitro tests confirmed the efficiency of HTyr-MC as a radical scavenger [28] and the lack of cytotoxicity makes it possible to be used as a preservative for food applications [35]. Recently, HTyr-MC was added into poly(vinyl alcohol) (PVA) matrices to obtain novel PVA-based binary films useful for packaging applications, to preserve food susceptible to oxidation [36].…”

Hydroxytyrosol-Derived Compounds: A Basis for the Creation of New Pharmacological Agents for Cancer Prevention and Therapy

“…54 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 synthesis was performed according to the procedure depicted in Scheme 14. First, HTyr was converted into the corresponding 3,4-dihydroxyphenethyl chloro and iododerivatives by using PPh 3 and CCl 4 in CH 3 CN and a mixture of PPh 3 , I 2 and imidazole.…”

“…The authors suggested that the enhanced antioxidant activity was due in part to an increased bioavailability of both HTyr derivatives and also to their enzymatic conversion by the cell into the parental HTyr compound. 44 A more recent study by Bernini et al reported the synthesis of HTyr catecholic analogs 35-37 and a large panel of their fatty acid esters 38-73 54. In this study, the antioxidant activity of these compounds (10 µM) was evaluated in L6 rat muscle cells through the DCF assay.…”