10597-60-1Relevant articles and documents
Synthesis of hydroxytyrosol, 2-hydroxyphenylacetic acid, and 3-hydroxyphenylacetic acid by differential conversion of tyrosol isomers using Serratia marcescens strain
Allouche, Noureddine,Sayadi, Sami
, p. 6525 - 6530 (2005)
We investigated to develop an effective procedure to produce the potentially high-added-value phenolic compounds through bioconversion of tyrosol isomers. A soil bacterium, designated Serratia marcescens strain, was isolated on the basis of its ability to grow on p-tyrosol (4-hydroxyphenylethanol) as a sole source of carbon and energy. During growth on p-tyrosol, Ser. marcescens strain was capable of promoting the formation of hydroxytyrosol. To achieve maximal hydroxytyrosol yield, the growth state of the culture utilized for p-tyrosol conversion as well as the amount of p-tyrosol that was treated were optimized. The optimal yield of hydroxytyrosol (80%) was obtained by Ser. marcescens growing cells after a 7-h incubation using 2 g/L of p-tyrosol added at the end of the exponential phase to a culture pregrown on 1 g/L of p-tyrosol. Furthermore, the substrate specificity of the developed biosynthesis was investigated using m-tyrosol (3-hydroxyphenylethanol) and o-tyrosol (2-hydroxyphenylethanol) as substrates. Ser. marcescens strain transformed completely m-tyrosol and o-tyrosol into 3-hydroxyphenylacetic acid and 2-hydroxyphenylacetic acid, respectively, via the oxidation of the side chain carbon of the treated substrates. This proposed procedure is an alternative approach to obtain hydroxytyrosol, 2-hydroxyphenylacetic acid, and 3-hydroxyphenylacetic acid in an environmentally friendly way which could encourage their use as alternatives in the search for replacement of synthetic food additives.
Antioxidant activity of olive phenols: Mechanistic investigation and characterization of oxidation products by mass spectrometry
Roche, Marjolaine,Dufour, Claire,Mora, Nathalie,Dangles, Olivier
, p. 423 - 430 (2005)
In this work, the antioxidant activity of olive phenols is first characterized by their stoichiometries ntot (number of radicals trapped per antioxidant molecule) and their rate constants for the first H-atom abstraction k1, by the stable radical DPPH. It appears that oleuropein, hydroxytyrosol and caffeic acid have the largest k1 values, whereas dihydrocaffeic acid, an intestinal metabolite of caffeic acid, is the best antioxidant in terms of ntot. For phenols with a catechol moiety ntot1 is higher than two, implying an antioxidant effect of their primarily formed oxidation products. A HPLC-MS analysis of the main products formed in the AAPH-induced oxidation of olive phenols reveals the presence of dimers and trimers. With hydroxytyrosol and dihydrocaffeic acid, oligomerization can take place with the addition of water molecules. The antioxidant activity of olive phenols is then evaluated by their ability to inhibit the AAPH-induced peroxidation of linoleic acid in SDS micelles. It is shown that olive phenols and quercetin act as retardants rather than chain breakers like α-tocopherol. From a detailed mechanistic investigation, it appears that the inhibition of lipid peroxidation by olive phenols can be satisfactorily interpreted by assuming that they essentially reduce the AAPH-derived initiating radicals. Overall, olive phenols prove to be efficient scavengers of hydrophilic peroxyl radicals with a long lasting antioxidant effect owing to the residual activity of some of their oxidation products.
Hydroxytyrosol lipophilic analogues: Enzymatic synthesis, radical scavenging activity and DNA oxidative damage protection
Grasso, Salvatore,Siracusa, Laura,Spatafora, Carmela,Renis, Marcella,Tringali, Corrado
, p. 137 - 152 (2007)
The olive oil phenol hydroxytyrosol (3), as well its metabolite homovanillic alcohol (4), were subjected to chemoselective lipase-catalysed acylations, affording with good yield 10 derivatives (5-14) bearing C2, C3, C4, C10 and C18 acyl chains at C-1. Hydroxytyrosol (3) and its lipophilic derivatives showed very good DPPH{radical dot} radical scavenging activity. Compounds 3, 4 and their lipophilic analogues 5-14 were subjected to the atypical Comet test on whole blood cells: 3 and its analogues 5 and 6, with little hydrophobic character (log P ≤ 1.20), showed a good protective effect against H2O2 induced oxidative DNA damage. The homovanillic alcohol 4 and its analogues 10-14 resulted scarcely effective both as radical scavengers and antioxidant agents.
Synthesis of tritium-labeled hydroxytyrosol, a phenolic compound found in olive oil
Tuck, Kellie L.,Tan, Hai-Wei,Hayball, Peter J.
, p. 4087 - 4090 (2000)
(3,4-Dihydroxyphenyl)ethanol, commonly known as hydroxytyrosol (1), is the major phenolic antioxidant compound in olive oil, and it contributes to the beneficial properties of olive oil. Bioavailability and metabolism studies of this compound are extremely limited, in part, related to unavailability of radiolabeled compound. Studies with radiolabeled compounds enable use of sensitive radiometric analytical methods as well as aiding elucidation of metabolic and elimination pathways. In the present study a route for the formation of hydroxytyrosol (1), by reduction of the corresponding acid 2 with tetrabutylammonium boronate, was found. Methods for the incorporation of a tritium label in 1 were investigated and successfully accomplished. Tritiated hydroxytyrosol (1t) was synthesized with a specific activity of 66 Ci/mol. The stability of unlabeled and labeled hydroxytyrosol was also investigated.
Determination of phenols, flavones, and lignans in virgin olive oils by solid-phase extraction and high-performance liquid chromatography with diode array ultraviolet detection
Mateos, Raquel,Espartero, Jose Luis,Trujillo, Mariana,Rios,Leon-Camacho, Manuel,Alcudia, Felipe,Cert, Arturo
, p. 2185 - 2192 (2001)
A simple analytical method for the quantitative determination of phenols, flavones, and lignans in virgin olive oils was developed. The polar fraction was isolated from small amounts of oil sample (2.5 g) by solid-phase extraction (SPE) using diol-phase cartridges, and the extract was analyzed by reversed-phase HPLC coupled with diode array LTV detection. Chromatographic separation of pinoresinol, cinnamic acid, and 1-acetoxypinoresinol was achieved. Repeatability (RSD 90%), and response factors for each identified component were determined. SPE on amino-phase cartridges was used for isolating acidic phenols and as an aid for phenol identification. For the first time, 2-(4-hydroxyphenyl)ethyl acetate was detected in olive oils. The aldehydic structure of the ligstroside aglycon was confirmed by NMR spectroscopy. The colorimetric determination of total o-diphenolic compounds by reaction with molybdate was consistent with their HPLC determination. Differences between results obtained by liquid-liquid extraction and SPE were not statistically significant.
A highly convenient synthesis of hydroxytyrosol and its recovery from agricultural waste waters
Capasso, Renato,Evidente, Antonio,Avolio, Salvatore,Solla, Francesco
, p. 1745 - 1748 (1999)
Hydroxytyrosol, a polyphenol with very interesting antioxidant properties, which naturally occurs in virgin olive oil and mainly in olive oil mill waste waters, was synthesized by reducing 3,4-dihydroxyphenylacetic acid with LiAlH4 in tetrahydrofuran under refluxing for 2 h. The yield of reaction was 82.8%. The spectroscopic and HPLC data of the synthesized compound proved to coincide fully with those of a pure sample obtained by the chromatographic recovery from olive oil mill waste waters (yield = 91 mg/L). This synthetic method appears to be the most convenient compared with those reported in the literature and is more convenient than the chromatographic recovery. The tri- and diacetyl derivatives of the synthetic compound were also prepared for structure-bioactivity relationship studies. A brief discussion is given on the economical and ecological aspects regarding the production of hydroxytyrosol.
Oxidative cleavage of 1-aryl-isochroman derivatives using the: Trametes villosa laccase/1-hydroxybenzotriazole system
Bernini, Roberta,Crisante, Fernanda,D'Acunzo, Francesca,Gentili, Patrizia,Ussia, Emanuele
, p. 3314 - 3322 (2016)
The oxidative cleavage of the dihydropyran ring of 1-aryl-isochroman derivatives was carried out for the first time under green chemistry conditions in the presence of the Trametes villosa laccase/1-hydroxybenzotriazole system in buffered water/1,4-dioxane and buffered water/dimethyl carbonate as reaction media. The corresponding oxidation products [2-(2-hydroxyethyl)benzophenone derivatives] were obtained in different yields depending on the substituents on phenyl and isochroman rings. These compounds are useful intermediates for the synthesis of anticancer agents and neuroprotective drugs.
Determination of hydroxytyrosol in plasma by HPLC
Ruiz-Gutierrez,Juan,Cert,Planas
, p. 4458 - 4461 (2000)
Hydroxytyrosol (2-(3,4-dihydroxyphenyl)ethanol), a phenolic compound present in extravirgin olive oil, has been reported to contribute to the prevention of cardiovascular disease. The present study describes an accurate and reproducible reversed-phase HPLC method to measure hydroxytyrosol in plasma. This compound was extracted from acidified plasma by solid-phase extraction using an Oasis HLB copolymer. The plasma sample was rinsed with water and methanol in water (5:95; v/v). Hydroxytyrosol was eluted with methanol, which was subsequently evaporated under a nitrogen stream. Analysis by HPLC with diode array-UV detection was carried out using a C18 column and a gradient elution with acidified water and methanol/acetonitrile (50:50; v/v). The method was validated by the analyses of plasma samples spiked with pure hydroxytyrosol, obtaining a linear correlation (0.9986) and precision with a coefficient of variation ranging from 0.79 to 6.66%. The recovery was ?100%, and the limit of detection was 37 ng/mL. The oral administration of hydroxytyrosol to rats and its subsequent detection in plasma showed that the method is suitable for pharmacokinetic studies.
Characterization of Type IV Carboxylate Reductases (CARs) for Whole Cell-Mediated Preparation of 3-Hydroxytyrosol
Horvat, Melissa,Fritsche, Susanne,Kourist, Robert,Winkler, Margit
, p. 4171 - 4181 (2019)
Fragrance and flavor industries could not imagine business without aldehydes. Processes for their commercial production raise environmental and ecological concerns. The chemical reduction of organic acids to aldehydes is challenging. To fulfill the demand of a mild and selective reduction of carboxylic acids to aldehydes, carboxylic acid reductases (CARs) are gaining importance. We identified two new subtype IV fungal CARs from Dichomitus squalens CAR (DsCAR) and Trametes versicolor CAR (Tv2CAR) in addition to literature known Trametes versicolor CAR (TvCAR). Expression levels were improved by the co-expression of GroEL-GroES with either the trigger factor or the DnaJ-DnaK-GrpE system. Investigation of the substrate scope of the three enzymes revealed overlapping substrate-specificities. Tv2CAR and DsCAR showed a preferred pH range of 7.0 to 8.0 in bicine buffer. TvCAR showed highest activity at pH 6.5 to 7.5 in MES buffer and slightly reduced activity at pH 6.0 or 8.0. TvCAR appeared to tolerate a wider pH range without significant loss of activity. Type IV fungal CARs optimal temperature was in the range of 25–35 °C. TvCAR showed a melting temperature (Tm) of 55 °C indicating higher stability compared to type III and the other type IV fungal CARs (Tm 51–52 °C). Finally, TvCAR was used as the key enzyme for the bioreduction of 3,4-dihydroxyphenylacetic acid to the antioxidant 3-hydroxytyrosol (3-HT) and gave 58 mM of 3-HT after 24 h, which correlates to a productivity of 0.37 g L?1 h?1.
High-yielding preparation of a stable precursor of hydroxytyrosol by total synthesis and from the natural glycoside oleuropein
Gambacorta, Augusto,Tofani, Daniela,Bernini, Roberta,Migliorini, Antonella
, p. 3386 - 3391 (2007)
The unprecedented acetonide of the antioxidant hydroxytyrosol has been synthesized by a two-step high-yielding procedure and found to be both purifiable by chromatography and stable over a wide pH range. The protection stabilizes hydroxytyrosol against oxidation, thereby allowing long-term storage. The protection can quantitatively be removed, under nonaqueous conditions, to afford pure hydroxytyrosol suitable for use as an additive in food and cosmetic preparations. Extension of the same methodology to the natural and easily accessible glycoside oleuropein, followed by saponification of the resulting complex mixture of acetonides, allowed hydroxytyrosol acetonide to be recovered in high yield. This constitutes a new interesting methodology to obtain the antioxidant hydroxytyrosol.
