Oxidative chemistry of the natural antioxidant hydroxytyrosol: hydrogen peroxide-dependent hydroxylation and hydroxyquinone/o-quinone coupling pathways

Lucia, Maria De; Panzella, Lucia; Pezzella, Alessandro; Napolitano, Alessandra; d’Ischia, Marco

doi:10.1016/j.tet.2005.10.055

Cited by 44 publications

(40 citation statements)

References 19 publications

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“…A wide number of examples of ohydroxylation of phenolic compounds and oxidative demethylation of 2-methoxyphenols for the synthesis of biologically and industrially relevant catechols are described in a recent review [34]. Specifically, the (S)IBX-mediated oxidation of tyrosol 8 and homovanillyl alcohol 9 followed by an in situ sodium dithionite reduction produced HTyr in modest yields [35,36] (Scheme 7, Table 1, entries 1,3). The efficiency and eco-friendly character of IBXpolystyrene ( Table 1, entries 2,4) to give HTyr are noteworthy.…”

Section: Synthetic Proceduresmentioning

confidence: 99%

Naturally Occurring Hydroxytyrosol: Synthesis and Anticancer Potential

Bernini¹,

Merendino²,

Romani³

et al. 2013

CMC

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Several epidemiological and animal studies have suggested that polyphenols, a group of secondary plant metabolites occurring mainly in the plant kingdom, may have a protective effect against some chronic degenerative diseases such as cancer. Polyphenols are part of the human diet, being present in vegetal food and beverages. Among them, an olive biophenol named hydroxytyrosol [2-(3,4-dihydroxyphenyl)ethanol, HTyr] has recently received particular attention because of its antioxidant, antiproliferative, pro-apoptotic, and anti-inflammatory activities, which have the potential to specifically counteract all cancer hallmarks, thus representing the expectant biological activities underlying the anti-tumor properties of this polyphenol. After a description of the synthetic procedures to prepare pure HTyr, this review takes into consideration the chemopreventive and chemotherapeutic potential of HTyr as the result of its antioxidant, antiproliferative and anti-inflammatory activities. In particular, the review is focused on the current knowledge of the main cellular and molecular mechanisms used by HTyr to affect carcinogenesis, highlighting the specific oncogenic and inflammatory signaling pathways potentially targeted by HTyr.

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Section: Synthetic Proceduresmentioning

confidence: 99%

Naturally Occurring Hydroxytyrosol: Synthesis and Anticancer Potential

Bernini¹,

Merendino²,

Romani³

et al. 2013

CMC

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“…The mechanisms regulating the beneficial effects of HT are not completely understood. Earlier studies have shown that HT in the presence of peroxidase/H 2 O 2 (PBS, pH 7.4) undergoes oxidation initiating catecholquinone coupling to yield methanooxocinobenzodioxinone (De Lucia et al 2006;Vogna et al 2003). Although this oxidative chemistry of HT supports the proposed role of catechols (olive phenols) as scavengers for H 2 O 2 , it is unclear if such a chemical reaction occurs in biological system at a rate that is significant.…”

Section: Introductionmentioning

confidence: 90%

“…Spectroscopy measurements of catechol-semiquinonequinone redox cycling of hydroxytyrosol HT in the presence of peroxidase undergoes oxidation to initiate catechol-quinone coupling (De Lucia et al 2006;Vogna et al 2003); hydroquinones and quinones are known to produce relatively stable semiquinone radicals (Bachur et al 1978). EPR spectroscopy was used to examine semiquinone radical from the one-electron oxidation of HT.…”

Section: Sodium Cyanide Was Used To Distinguish Between Mnsod and Cuzmentioning

confidence: 99%

MnSOD activity regulates hydroxytyrosol-induced extension of chronological lifespan

Sarsour

Kumar

Kalen

et al. 2011

AGE

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Chronological lifespan (CLS) is defined as the duration of quiescence in which normal cells retain the capacity to reenter the proliferative cycle. This study investigates whether hydroxytyrosol (HT), a naturally occurring polyphenol found in olives, extends CLS in normal human fibroblasts (NHFs). Quiescent NHFs cultured for a long duration (30-60 days) lose their capacity to repopulate. Approximately 60% of these cells exit the cell cycle permanently; a significant increase in the doubling time of the cell population was observed. CLS was extended in quiescent NHFs that were cultured in the presence of HT for 30-60 days. HT-induced extension of CLS was associated with an approximately 3-fold increase in manganese superoxide dismutase (MnSOD) activity while there was no change in copper-zinc superoxide dismutase, catalase, or glutathione peroxidase protein levels. Quiescent NHFs overexpressing a dominant-negative mutant form of MnSOD failed to extend CLS. HT suppressed ageassociated increase in mitochondrial ROS levels. Results from spectroscopy assays indicate that HT in the presence of peroxidases can undergo catechol-semiquinone-quinone redox cycling generating superoxide, which in a cellular context can activate the antioxidant system, e.g., MnSOD expression. These results demonstrate that HT extends CLS by increasing MnSOD activity and decreasing age-associated mitochondrial reactive oxygen species accumulation.

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“…In a preceding work the tetra-acetate derivative of 7 was described as one of the products obtained in low yields, from hydroxytyrosol when submitted to oxidative conditions. 13 …”

Section: Synthesis Of the 25-dihydroxytyrosolmentioning

confidence: 99%

An expedient synthesis of 2,5-dihydroxytyrosol and studies on its effects on cell growth inhibition

Ammendola¹,

Mosca²,

Bovicelli

2008

Arkivoc

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Many antioxidant molecules are described to have an oxidant activity causing cell damages. Some dietary phytophenols, in spite of their beneficial effects, have been found to promote lipid peroxidation and DNA breaks. Hydroxytyrosol, a phytophenol extracted from olive oil and wine, has been found to act as an antioxidant. Furthermore it also inhibits the growth of several bacteria and fungi. During recent studies on the synthesis of antioxidant polyphenols from tyrosol, a phenol recovered in high amount from olive oil wastes, we prepared 2,4,5-trihydroxy-(2-hydroxyethyl)-phenol (2,5-dihydroxytyrosol). We observed its biological effect on cultured human and bacterial cells showing that its toxic activity is more potent than tyrosol and hydroxytyrosol resulting toxicity at 5 µM whereas its parent molecules are toxic at a dose of about 100 µM.

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Oxidative chemistry of the natural antioxidant hydroxytyrosol: hydrogen peroxide-dependent hydroxylation and hydroxyquinone/o-quinone coupling pathways

Cited by 44 publications

References 19 publications

Naturally Occurring Hydroxytyrosol: Synthesis and Anticancer Potential

Naturally Occurring Hydroxytyrosol: Synthesis and Anticancer Potential

MnSOD activity regulates hydroxytyrosol-induced extension of chronological lifespan

An expedient synthesis of 2,5-dihydroxytyrosol and studies on its effects on cell growth inhibition

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