Sustainable Synthesis of New Antioxidants from Hydroxytyrosol by Direct Biocatalytic Esterification in Ionic Liquids

Hydroxytyrosol (HT) is a nutraceutical compound, mainly found in the fruit, leaves and waste from the olive oil industry, known for exhibiting one of the highest antioxidant activities among molecules of natural origin. To harness this bioactivity in cosmetics, pharmaceuticals and the food industry,...

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Main Authors: Susana Nieto, Inmaculada Lozano, Francisco J. Ruiz, Jose F. Costa, Rocio Villa, Pedro Lozano
Format: Article
Language:English
Published: MDPI AG 2024-10-01
Series:Molecules
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Online Access:https://www.mdpi.com/1420-3049/29/21/5057
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author Susana Nieto
Inmaculada Lozano
Francisco J. Ruiz
Jose F. Costa
Rocio Villa
Pedro Lozano
author_facet Susana Nieto
Inmaculada Lozano
Francisco J. Ruiz
Jose F. Costa
Rocio Villa
Pedro Lozano
author_sort Susana Nieto
collection DOAJ
description Hydroxytyrosol (HT) is a nutraceutical compound, mainly found in the fruit, leaves and waste from the olive oil industry, known for exhibiting one of the highest antioxidant activities among molecules of natural origin. To harness this bioactivity in cosmetics, pharmaceuticals and the food industry, it is essential to modify the hydrophilicity of HT to enhance its compatibility with lipid-based mixtures. This chemical modification must be carried out with high selectivity to avoid compromising its radical scavenging activity. This work presents a highly efficient and selective approach to perform the biocatalytic esterification of free fatty acids (FFAs) of different alkyl chain lengths with HT in a reaction medium based on the SLIL [C<sub>12</sub>mim][NTf<sub>2</sub>]. By using a 1:2 (mol/mol) HT:FFA mixture of substrates, the HT-monoester derivative was obtained up to 77% yield after 2 h at 80 °C. The optimized molar ratio of substrates, combined with the ability to recover the SLIL for further reuse, significantly reduces waste accumulation compared to other reported strategies and results in a more sustainable approach as demonstrated by different green metrics. The antioxidant activity of HT-monoester products was fully maintained with respect to that presented by the natural HT, being stable for at least 3 months at 4 °C, as demonstrated by the DPPH and FRAP antioxidant analysis.
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spelling doaj-art-abf72e29df574cca8227ec2d251afa9e2025-08-20T02:14:23ZengMDPI AGMolecules1420-30492024-10-012921505710.3390/molecules29215057Sustainable Synthesis of New Antioxidants from Hydroxytyrosol by Direct Biocatalytic Esterification in Ionic LiquidsSusana Nieto0Inmaculada Lozano1Francisco J. Ruiz2Jose F. Costa3Rocio Villa4Pedro Lozano5Departamento de Bioquímica y Biología Molecular B e Inmunología, Facultad de Química, Universidad de Murcia, E-30100 Murcia, SpainDepartamento de Bioquímica y Biología Molecular B e Inmunología, Facultad de Química, Universidad de Murcia, E-30100 Murcia, SpainDepartamento de Bioquímica y Biología Molecular B e Inmunología, Facultad de Química, Universidad de Murcia, E-30100 Murcia, SpainDepartamento de Bioquímica y Biología Molecular B e Inmunología, Facultad de Química, Universidad de Murcia, E-30100 Murcia, SpainDepartamento de Bioquímica y Biología Molecular B e Inmunología, Facultad de Química, Universidad de Murcia, E-30100 Murcia, SpainDepartamento de Bioquímica y Biología Molecular B e Inmunología, Facultad de Química, Universidad de Murcia, E-30100 Murcia, SpainHydroxytyrosol (HT) is a nutraceutical compound, mainly found in the fruit, leaves and waste from the olive oil industry, known for exhibiting one of the highest antioxidant activities among molecules of natural origin. To harness this bioactivity in cosmetics, pharmaceuticals and the food industry, it is essential to modify the hydrophilicity of HT to enhance its compatibility with lipid-based mixtures. This chemical modification must be carried out with high selectivity to avoid compromising its radical scavenging activity. This work presents a highly efficient and selective approach to perform the biocatalytic esterification of free fatty acids (FFAs) of different alkyl chain lengths with HT in a reaction medium based on the SLIL [C<sub>12</sub>mim][NTf<sub>2</sub>]. By using a 1:2 (mol/mol) HT:FFA mixture of substrates, the HT-monoester derivative was obtained up to 77% yield after 2 h at 80 °C. The optimized molar ratio of substrates, combined with the ability to recover the SLIL for further reuse, significantly reduces waste accumulation compared to other reported strategies and results in a more sustainable approach as demonstrated by different green metrics. The antioxidant activity of HT-monoester products was fully maintained with respect to that presented by the natural HT, being stable for at least 3 months at 4 °C, as demonstrated by the DPPH and FRAP antioxidant analysis.https://www.mdpi.com/1420-3049/29/21/5057lipasesbioactive moleculestailor synthesisneoteric solventsnutraceuticals
spellingShingle Susana Nieto
Inmaculada Lozano
Francisco J. Ruiz
Jose F. Costa
Rocio Villa
Pedro Lozano
Sustainable Synthesis of New Antioxidants from Hydroxytyrosol by Direct Biocatalytic Esterification in Ionic Liquids
Molecules
lipases
bioactive molecules
tailor synthesis
neoteric solvents
nutraceuticals
title Sustainable Synthesis of New Antioxidants from Hydroxytyrosol by Direct Biocatalytic Esterification in Ionic Liquids
title_full Sustainable Synthesis of New Antioxidants from Hydroxytyrosol by Direct Biocatalytic Esterification in Ionic Liquids
title_fullStr Sustainable Synthesis of New Antioxidants from Hydroxytyrosol by Direct Biocatalytic Esterification in Ionic Liquids
title_full_unstemmed Sustainable Synthesis of New Antioxidants from Hydroxytyrosol by Direct Biocatalytic Esterification in Ionic Liquids
title_short Sustainable Synthesis of New Antioxidants from Hydroxytyrosol by Direct Biocatalytic Esterification in Ionic Liquids
title_sort sustainable synthesis of new antioxidants from hydroxytyrosol by direct biocatalytic esterification in ionic liquids
topic lipases
bioactive molecules
tailor synthesis
neoteric solvents
nutraceuticals
url https://www.mdpi.com/1420-3049/29/21/5057
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AT inmaculadalozano sustainablesynthesisofnewantioxidantsfromhydroxytyrosolbydirectbiocatalyticesterificationinionicliquids
AT franciscojruiz sustainablesynthesisofnewantioxidantsfromhydroxytyrosolbydirectbiocatalyticesterificationinionicliquids
AT josefcosta sustainablesynthesisofnewantioxidantsfromhydroxytyrosolbydirectbiocatalyticesterificationinionicliquids
AT rociovilla sustainablesynthesisofnewantioxidantsfromhydroxytyrosolbydirectbiocatalyticesterificationinionicliquids
AT pedrolozano sustainablesynthesisofnewantioxidantsfromhydroxytyrosolbydirectbiocatalyticesterificationinionicliquids