Oxidation of aromatic monoterpenes with hydrogen peroxide catalysed by Mn(III) porphyrin complexes

Martins, R. R. L.; Neves, Maria G. P. M. S.; Silvestre, Armando J. D.; Silva, Artur M. S.; Cavaleiro, José A. S.

doi:10.1016/s1381-1169(98)00083-1

Cited by 70 publications

(32 citation statements)

References 9 publications

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“…Carvacrol (2-methyl-5-(1-methylethyl)-phenol) (Fig. 1) is a natural member of monoterpene phenol and is present in the volatile oils of Thymus vulgaris, Carum copticum, origanum and oregano (Martins et al 1999;Kisk and Roller 2005;Lampronti et al 2006). It has been safely used in our daily life: such as cosmetic ingredient, safe food additive in baked goods, sweets, beverages, and chewing gum.…”

Section: Introductionmentioning

confidence: 99%

Anti-proliferative and pro-apoptotic effect of carvacrol on human hepatocellular carcinoma cell line HepG-2

et al. 2011

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Carvacrol is one of the members of monoterpene phenol and is present in the volatile oils of Thymus vulgaris, Carum copticum, origanum and oregano. It is a safe food additive commonly used in our daily life, and few studies have indicated that carvacrol has anti-hepatocarcinogenic activities. The rationale of the study was to examine whether carvacrol affects apoptosis of human hepatoma HepG2 cells. In this study, we showed that carvacrol inhibited HepG2 cell growth by inducing apoptosis as evidenced by Hoechst 33258 stain and Flow cytometric (FCM) analysis. Incubation of HepG2 cells with carvacrol for 24 h induced apoptosis by the activation of caspase-3, cleavage of PARP and decreased Bcl-2 gene expression. These results demonstrated that a significant fraction of carvacrol treated cells died by an apoptotic pathway in HepG2 cells. Moreover, carvacrol selectively altered the phosphorylation state of members of the MAPK superfamily, decreasing phosphorylation of ERK1/2 significantly in a dosedependent manner, and activated phosphorylation of p38 but not affecting JNK MAPK phosphorylation. These results suggest that carvacrol may induce apoptosis by direct activation of the mitochondrial pathway, and the mitogen-activated protein kinase pathway may play an important role in the antitumor effect of carvacrol. These results have identified, for the first time, the biological activity of carvacrol in HepG2 cells and should lead to further development of carvacrol for liver disease therapy.

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Section: Introductionmentioning

confidence: 99%

Anti-proliferative and pro-apoptotic effect of carvacrol on human hepatocellular carcinoma cell line HepG-2

et al. 2011

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“…Such an intermediate is stabilized by the OH present in carvacrol (eq 1). 8 With the Cr-based catalyst, a 13% TQ yield was observed, along with small amounts of THQs and BQs. On the other hand, using the Fe-based catalyst, TQ formation was found to be 11.6% with a small amount of THQs.…”

Section: Decomposition Of H 2 Omentioning

confidence: 95%

“…In the literature, the oxidation of carvacrol with hydrogen peroxide has been studied by using Mn(III) porphyrin complexes, 8 Fe(III) meso-tetraphenylporphyrin or Fe(III) phthalocyanines, 10 and Keggin-type tungstoborates 11 under homogeneous conditions. Mn(III) porphyrin complexes exhibit high carvacrol conversions with a selectivity range of 70-99.6%.…”

Section: Decomposition Of H 2 Omentioning

confidence: 99%

“…8 Hydrogen peroxide is a preferred oxidant because it is easy to handle and its reaction produces only water as a byproduct. 2 Catalytic oxidation of aromatic monoterpenes with hydrogen peroxide is a reaction of industrial importance.…”

Section: Introductionmentioning

confidence: 99%

“…10 Oregano essential oils rich in carvacrol (47.6%) and thymol (25.1%) were easily oxidized by hydrogen peroxide to oils containing thymoquinone (19.1-63.3%) as the main component in the presence of Fe(III) meso-tetraphenylporphyrin or Fe(III) phthalocyanines. 10 The oxidation of carvacrol with hydrogen peroxide has also been studied using Mn(III) porhyrin complexes 8 and Keggin-type tungstoborates. 11 Oxidation of carvacrol by Keggin-type tungstoborates yielded a mixture of benzoquinones containing a small amount of thymoquinone, whereas for Mn(III) porphyrin complexes, oxidation of carvacrol selectively yielded thymoquinone.…”

Section: Introductionmentioning

confidence: 99%

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Liquid-Phase Oxidation of Carvacrol Using Zeolite-Encapsulated Metal Complexes

Güneş

Bayraktar

2005

Ind. Eng. Chem. Res.

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We report here the use of zeolite-encapsulated metal (salpn) complexes as catalysts in the oxidation reaction of the natural compound carvacrol in acetonitrile with hydrogen peroxide as the oxidant. No previous studies on the oxidation of carvacrol in the presence of metal salpn complexes have been reported. By using a general flexible ligand method, Cr(III), Fe(III), Bi(III), Ni(II), and Zn(II) complexes of N, N′-bis(salicylidene)propane-1,3-diamine (H 2 salpn) encapsulated in NaY zeolite were prepared. All catalysts were characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), and scanning electron microscopy (SEM) analyses to confirm the complex encapsulation. The activities of all prepared catalysts for the oxidation of carvacrol and hydrogen peroxide were tested. The performances of all catalysts were compared on the basis of the leaching test results and carvacrol conversions. Thymohydroquinone and benzoquinones were observed as byproducts at high conversions of carvacrol. No product was formed in the absence of a catalyst. Fe(salpn)-NaY catalyst exhibited the highest carvacrol conversion of 27.6% with a yield of 22.0%, followed by Cr(salpn)-NaY catalyst with 23.5% carvacrol conversion and a yield of 17.6%. Other catalysts have shown relatively lower performances in terms of carvacrol conversion and leaching. The Cr(salpn)-NaY catalyst was found to be a more efficient catalyst than others on the basis of leaching and activity tests. With the selected catalyst Cr (salpn)-NaY, the effects of temperature and carvacrol/hydrogen peroxide molar ratio on carvacrol oxidation reactions were investigated. Increasing the temperature from 40 to 60°C caused an increase in the thymoquinone yield from 6.2% to 16.0%. An increase in carvacrol/hydrogen peroxide molar ratio from 1 to 3 resulted in a decrease in the thymoquinone yield.

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Functionalization of sp ² and sp ³ Carbon Centers Catalyzed by Polyoxometalates and Metalloporphyrins

Simões

Santos

Neves

et al. 2013

Advances in Organometallic Chemistry and Catalysis

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Oxidation of aromatic monoterpenes with hydrogen peroxide catalysed by Mn(III) porphyrin complexes

Cited by 70 publications

References 9 publications

Anti-proliferative and pro-apoptotic effect of carvacrol on human hepatocellular carcinoma cell line HepG-2

Anti-proliferative and pro-apoptotic effect of carvacrol on human hepatocellular carcinoma cell line HepG-2

Liquid-Phase Oxidation of Carvacrol Using Zeolite-Encapsulated Metal Complexes

Functionalization of sp ² and sp ³ Carbon Centers Catalyzed by Polyoxometalates and Metalloporphyrins

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Oxidation of aromatic monoterpenes with hydrogen peroxide catalysed by Mn(III) porphyrin complexes

Cited by 70 publications

References 9 publications

Anti-proliferative and pro-apoptotic effect of carvacrol on human hepatocellular carcinoma cell line HepG-2

Anti-proliferative and pro-apoptotic effect of carvacrol on human hepatocellular carcinoma cell line HepG-2

Liquid-Phase Oxidation of Carvacrol Using Zeolite-Encapsulated Metal Complexes

Functionalization of sp 2 and sp 3 Carbon Centers Catalyzed by Polyoxometalates and Metalloporphyrins

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Functionalization of sp ² and sp ³ Carbon Centers Catalyzed by Polyoxometalates and Metalloporphyrins