10597-60-1Relevant articles and documents
Olea europaea chemicals repellent to Dacus oleae females
Scalzo,Scarpati,Verzegnassi,Vita
, p. 1813 - 1823 (1994)
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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.
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.
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.
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.
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.
HYDROXYCINNAMIC ACID ESTERS OF PHENETHYLALCOHOL GLYCOSIDES FROM REHMANNIA GLUTINOSA VAR. PURPUREA
Sasaki, Hiroshi,Nishimura, Hiroaki,Chin (Chen Zhengxiong), Masao,Mitsuhashi, Hiroshi
, p. 875 - 880 (1989)
Five new hydroxycinnamic acid esters of phenethylalcohol glycosides named jionosides C, D, E, A2 and B2, together with nine known compounds, have been isolated from roots of Rehmannia glutinosa var. purpurea and their structures elucidated on the basis of chemical and spectral evidences. Key Word Index-Rehmannia glutinosa var. purpurea; Scrophulariaceae; phenethylalcohol glycosides; jionosides.
Determination of Synthetic Hydroxytyrosol in Rat Plasma by GC-MS
Bai, Chen,Yan, Xiaojun,Takenaka, Makiko,Sekiya, Keizo,Nagata, Tadahiro
, p. 3998 - 4001 (1998)
2-(3,4-Dihydroxyphenyl)ethanol (DPE), the major phenolic compound in olive oil, may contribute the antioxidative activities and other beneficial effects to olive oil. However, the lack of commercial available DPE and procedures sensitive enough to quantitatively determine DPE in body fluids have limited the bioavailability and metabolism studies on this phenolic compound. In the present study, DPE was synthesized with high yield and high purity and administered orally to rats. DPE concentration in rat plasma, after absorption, was measured using a sensitive GC-MS-SIM method. The results indicated that the highest level of DPE in plasma was detected at 5-10 min after administration. During this period, the concentration of DPE fluctuated widely with the individual.
Production of hydroxytyrosol from hydroxylation of tyrosol by Rhodococcus pyridinivorans 3HYL DSM109178
Anissi, Jaouad,Sendide, Khalid,Ouardaoui, Abdelkrim,Benlemlih, Mohammed,El Hassouni, Mohammed
, p. 418 - 428 (2021)
Hydroxytyrosol (4-(2-hydroxyethyl)-1,2-benzenediol) is the most known bioactive compound from the plant Olea europaea (olive tree). To date, few biocatalysis processes allowing efficient production of hydroxytyrosol from potential substrates including, tyrosol (2-(4-hydroxy) phenyl ethanol) and tyrosine have been reported. In this paper, we report for a Gram-positive bacterium that produces hydroxytyrosol via conversion of tyrosol and/or L-tyrosine, identified as a Rhodococcus pyridinivorans based on phenotypic characteristics and 16S rDNA sequence, and designated R. pyridinivorans strain 3HYL DSM109178. Interestingly, strain 3HYL shows an outstanding production of hydroxytyrosol from tyrosol up to 16.4 ± 0.23 mmol/L with high kinetic parameters exceeding the reported values. However, a slight downstream metabolism of the product is assigned to the wild-type strain during the stationary phase of growth. The plasmid-cured strain was obtained using random chemical mutagenesis, designated R. pyridinivorans 3HYL-AO, and was able to produce hydroxytyrosol, with yields up to 21.75 ± 0.34 mmol/L. Moreover, the plasmid-cured strain exhibited a significant reduction in the transformation to its acetic acid forms compared to the wild-type strain as depicted by HPLC analysis. Comparison of kinetic data of the bioconversion/accumulation process between the wild type and mutant strain, in the presence and absence of L-tyrosine, and thus suggesting the occurrence of an upstream pathway for synthesis of tyrosol via (L)-tyrosine.
Whole-cell carboxylate reduction for the synthesis of 3-hydroxytyrosol
Napora-Wijata, Kamila,Robins, Karen,Osorio-Lozada, Antonio,Winkler, Margit
, p. 1089 - 1095 (2014)
3-Hydroxytyrosol (3-HT) is a phenolic antioxidant that has a number of beneficial effects on human health and is a valuable building block in the synthesis of various pharmaceuticals. Herein, we report a new method for the production of 3-HT through reduction of 3,4-dihydroxyphenylacetic acid. The reduction was performed in whole Escherichia coli BL21 (DE3) cells overexpressing carboxylic acid reductase from Nocardia and phosphopantetheinyl transferase from E. coli. An endogenous E. coli aldehyde reducing activity turned out to be highly efficient for further reduction of the aldehyde intermediate to the desired alcohol. The influence of different buffer components, cofactors, and cofactor recycling systems was investigated. A very economic combination of glucose, citrate, and air proved sufficient for recycling of the essential cofactors ATP and NAD(P)H. Selected crucial parameters were then further optimized within a "design of experiments" approach. Finally, first preparative-scale bioreductions resulted in pure 3-HT. All in a cell's work: An enzymatic carboxylic acid reduction is the key step of a new route to the potent antioxidant from olives: 3-hydroxytyrosol. In addition to the substrate 3,4-dihydroxyphenylacetic acid, only citrate, glucose, and oxygen are required to regenerate the essential cofactors ATP and NAD(P)H. CAR=carboxylate reductase; PPTase= phosphopantetheinyl transferase.
Acteoside as the analgesic principle of Cedron (Lippia triphylla), a Peruvian medicinal plant
Nakamura, Tomonori,Okuyama, Emi,Tsukada, Atsushi,Yamazaki, Mikio,Satake, Motoyoshi,Nishibe, Sansei,Deyama, Takeshi,Moriya, Akira,Maruno, Masao,Nishimura, Hiroaki
, p. 499 - 504 (1997)
Acteoside (verbascoside) was isolated as an analgesic principle from Cedron (leaves and stem of Lippia triphylla (L'HER) O. KUNTZE; Verbenaceae), a Peruvian medicinal plant, by activity-guided separation. The compound exhibited analgesia on acetic acid-induced writhing and on tail pressure pain in mice by the oral administration of 300mg/kg and 100mg/kg, respectively. Acteoside also caused weak sedation by its effect on the prolongation of pentobarbital-induced anesthesia and on the depression of locomotion enhanced by methamphetamine. An intravenous injection of acteoside reduced the effective dose to 2mg/kg by the writhing method. Thirteen related compounds were tested for the activity by intravenous and oral administration to obtain information on the active structure.
Oxidative chemistry of the natural antioxidant hydroxytyrosol: Hydrogen peroxide-dependent hydroxylation and hydroxyquinone/o-quinone coupling pathways
De Lucia, Maria,Panzella, Lucia,Pezzella, Alessandro,Napolitano, Alessandra,D'Ischia, Marco
, p. 1273 - 1278 (2006)
Oxidation of the natural antioxidant hydroxytyrosol (1) with peroxidase/H2O2 in phosphate buffer at pH 7.4 led to the formation of two main ethyl acetate-extractable products. These could be isolated by preparative TLC after reduction and acetylation, and were identified as the tetraacetyl derivative of 2-(2,4,5-trihydroxyphenyl)ethanol (3) and the heptaacetyl derivative of the pentahydroxybiphenyl 4 by 2D NMR and MS analysis. Similar oxidation of 4-methylcatechol gave, after the same work-up, the acetylated derivatives of 1,2,4-trihydroxy-5-methylbenzene (5) and the pentahydroxybiphenyl 6. Mechanistic experiments suggested that hydrogen peroxide affects the course of the oxidation of 1 by adding to the first formed o-quinone to give a hydroxyquinone intermediate. This could bring nucleophilic attack to the o-quinone of 1 to give the dimer 4. These results disclose novel oxidative pathways of 4-alkylcatechols and provide an improved chemical basis to enquire into the mechanism of the antioxidant action of 1.
Novel approach to the detection and quantification of phenolic compounds in olive oil based on 31P nuclear magnetic resonance spectroscopy
Christophoridou, Stella,Dais, Photis
, p. 656 - 664 (2006)
31P NMR spectroscopy has been employed to detect and quantify phenolic compounds in the polar fraction of virgin olive oil. This novel analytical method is based on the derivatization of the hydroxyl and carboxyl groups of phenolic compounds with 2-chloro-4,4,5,5-tetramethyldioxaphospholane and the identification of the phosphitylated compounds on the basis of the 31P chemical shifts. Quantification of a large number of phenolic compounds in virgin olive oil can be accomplished by integration of the appropriate signals in the 31P NMR spectrum and the use of the phosphitylated cyclohexanol as internal standard. Finally, the validity of this technique for quantitative measurements was thoroughly examined.
A two-step process for the synthesis of hydroxytyrosol
Ziosi, Paolo,Paolucci, Claudio,Santarelli, Francesco,Tabanelli, Tommaso,Passeri, Sauro,Cavani, Fabrizio,Righi, Paolo
, p. 2202 - 2210 (2018)
A new process for the synthesis of hydroxytyrosol (3,4-dihy-droxyphenylethanol), the most powerful natural antioxidant currently known, by means of a two-step approach is reported. Catechol is first reacted with 2,2-dimethoxyacetaldehyde in basic aqueous medium to produce the corresponding mandelic derivative with > 90 % conversion of the limiting reactant and about 70 % selectivity to the desired para-hydroxyalkylat-ed compound. Thereafter, the intermediate is hydrogenated to hydroxytyrosol by using a Pd/C catalyst, with total conversion of the mandelic derivative and 68 % selectivity. This two-step process is the first example of a synthetic pathway for hydroxytyrosol that does not involve the use of halogenated components or reduction methodologies that produce stoichiometric waste. It also avoids the complex procedure currently used for hydroxytyrosol purification when it is extracted from wastewa-ter of olive oil production.
Regioselectivity of Cobalamin-Dependent Methyltransferase Can Be Tuned by Reaction Conditions and Substrate
Pompei, Simona,Grimm, Christopher,Farnberger, Judith E.,Schober, Lukas,Kroutil, Wolfgang
, p. 5977 - 5983 (2020)
Regioselective reactions represent a significant challenge for organic chemistry. Here the regioselective methylation of a single hydroxy group of 4-substituted catechols was investigated employing the cobalamin-dependent methyltransferase from Desulfitobacterium hafniense. Catechols substituted in position four were methylated either in meta- or para-position to the substituent depending whether the substituent was polar or apolar. While the biocatalytic cobalamin dependent methylation was meta-selective with 4-substituted catechols bearing hydrophilic groups, it was para-selective for hydrophobic substituents. Furthermore, the presence of water miscible co-solvents had a clear improving influence, whereby THF turned out to enable the formation of a single regioisomer in selected cases. Finally, it was found that also the pH led to an enhancement of regioselectivity for the cases investigated.
Isolation of natural compounds from Phlomis stewartii showing α-glucosidase inhibitory activity
Jabeen, Bushra,Riaz, Naheed,Saleem, Muhammad,Naveed, Muhammad Akram,Ashraf, Muhammad,Alam, Umber,Rafiq, Hafiza Mehwish,Tareen, Rasool Bakhsh,Jabbar, Abdul
, p. 443 - 448 (2013)
Stewartiiside (1), a phenylethanoid glycoside and three 28-nortriterpenoids: stewertiisins A-C [(17R)-19(18 → 17)-abeo-3α, 18β,23,24-tetrahydroxy-28-norolean-12-ene, 2; (17R)-19(18 → 17)-abeo-2α,16β,18β,23,24-pentahydroxy-28-norolean-12-en-3-one, 3; (17R)-19(18 → 17)-abeo-2α,3α,23,24-tetrahydroxy-28- noroleane-11,13-diene, 4] together with eight known compounds: lunariifolioside (5), notohamosin A (6), phlomispentanol (7), isorhamnetin 3-(6-p-coumaroyl)- β-d-glucopyranoside (8), tiliroside (9), caffeic acid (10), p-hydrxybenzoic acid (11) and oleanolic acid (12) were isolated from the ethyl acetate soluble fraction of the methanolic extract of whole plant of Phlomis stewartii. The structures of these isolates (1-12) were elucidated by the combination of 1D (1H and 13C NMR), 2D (HMQC, HMBC COSY, NOESY) NMR spectroscopy and mass spectrometry (EIMS, HREIMS, FABMS, HRFABMS) and in comparison with literature data of related compounds. All the isolates (1-12) showed α-glucosidase inhibitory activity with IC50 values ranging between 14.5 and 355.4 μM, whereas, compounds 1, 5, 9 and 10 showed promising α-glucosidase inhibitory activity with IC50 values below 30 μM.
Hydroxytyrosol, a phenolic compound from virgin olive oil, prevents macrophage activation
Maiuri, Maria Chiara,De Stefano, Daniela,Di Meglio, Paola,Irace, Carlo,Savarese, Maria,Sacchi, Raffaele,Cinelli, Maria Pia,Carnuccio, Rosa
, p. 457 - 465 (2005)
We investigated the effect of hydroxytyrosol (HT), a phenolic compound from virgin olive oil, on inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in J774 murine macrophages stimulated with lipopolysaccharide (LPS). Incubation of cells with LPS caused an increase in iNOS and COX-2 mRNA and protein level as well as ROS generation, which was prevented by HT. In addition, HT blocked the activation of nuclear factor-κB (NF-κB), signal transducer and activator of transcription-1α (STAT-1α) and interferon regulatory factor-1 (IRF-1). These results, showing that HT down-regulates iNOS and COX-2 gene expression by preventing NF-κB, STAT-1α and IRF-1 activation mediated through LPS-induced ROS generation, suggest that it may represent a non-toxic agent for the control of pro-inflammatory genes. Springer-Verlag 2005.
Production of high hydroxytyrosol yields via tyrosol conversion by Pseudomonas aeruginosa immobilized resting cells
Bouallagui, Zouhaier,Sayadi, Sami
, p. 9906 - 9911 (2006)
An immobilized whole cell system was successfully performed to produce the most powerful antioxidant, hydroxytyrosol. Bioconversion of tyrosol into hydroxytyrosol was achieved via the immobilization of Pseudomonas aeruginosa resting cells in calcium alginate beads. Immobilization was advantageous as it allows immobilized cells to tolerate a greater tyrosol concentration than free cells. The bioconversion yield reached 86% in the presence of 5 g L-1 of tyrosol when cells immobilized in alginate beads were carried out in single batches. Evaluation of kinetic parameters showed the maintenance of the same catalytic efficiency expressed as Kcat/Km for both free and immobilized cells. The use of immobilized cells in repeated batches demonstrated a notable activity stabilization since the biocatalyst reusability was extended for at least four batches with a molar yield greater than 85%.
Rapid biosynthesis of phenolic glycosides and their derivatives from biomass-derived hydroxycinnamates
Zhao, Mingtao,Hong, Xulin,Abdullah,Yao, Ruilian,Xiao, Yi
supporting information, p. 838 - 847 (2021/02/09)
Biomass-derived hydroxycinnamates (mainly includingp-coumaric acid and ferulic acid), which are natural sources of aromatic compounds, are highly underutilized resources. There is a need to upgrade them to make them economically feasible. Value-added phenolic glycosides and their derivatives, both belonging to a class of plant aromatic natural products, are widely used in the nutraceutical, pharmaceutical, and cosmetic industries. However, their complex aromatic structures make their efficient biosynthesis a challenging process. To overcome this issue, we created three novel synthetic cascades for the biosynthesis of phenolic glycosides (gastrodin, arbutin, and salidroside) and their derivatives (hydroquinone, tyrosol, hydroxytyrosol, and homovanillyl alcohol) fromp-coumaric acid and ferulic acid. Moreover, because the biomass-derived hydroxycinnamates directly provided aromatic units, the cascades enabled efficient biosynthesis. We achieved substantially high production rates (up to or above 100-fold enhancement) relative to the glucose-based biosynthesis. Given the ubiquity of the aromatic structure in natural products, the use of biomass-derived aromatics should facilitate the rapid biosynthesis of numerous aromatic natural products.
A new secoiridoid glucoside from Olea europaea
Ishimaru, Kanji,Kotoda, Nobuhiro,Matsuo, Yosuke,Nakayama, Hideyuki,Nishi, Nanami,Tanaka, Takashi
, (2022/02/25)
A new phenolic glucoside (1), olerikaside, and other known secoiridoid glucosides [oleuropein (2), demethyl oleuropein (3), oleoside 11-methyl ester (4), oleoside 7, 11-dimethyl ester (5), 7-β-D-glucopyranosyl 11-methyl oleoside (6), secoxyloganin (7), ilicifolioside B (8), hydroxytyrosol (9), and hydroxytyrosol glucosides (10–12)] were isolated from unprocessed olive fruits of Olea europaea cv. “Lucca”. The chemical structure of olerikaside (1) was clarified based on spectroscopy and chemical analysis data.
