Possible Controversy over Dietary Polyphenols:  Benefits vs Risks

Lambert, Joshua D.; Sang, Shengmin; Yang, Chung S.

doi:10.1021/tx7000515

Cited by 221 publications

(154 citation statements)

References 25 publications

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“…1A). However, unlike most phytopolyphenols (Lambert et al, 2007;Halliwell, 2008), simple 1,3-diketones, such as 2-ACP, are chemically stable, relatively water-soluble compounds that are rapidly absorbed and have large volumes of distribution (Ballantyne and Cawley, 2001;LoPachin et al, 2011). Furthermore, the acute animal toxicity of these chemicals is low (LD 50 .…”

Section: Discussionmentioning

confidence: 99%

2-Acetylcyclopentanone, an Enolate-Forming 1,3-Dicarbonyl Compound, Is Cytoprotective in Warm Ischemia-Reperfusion Injury of Rat Liver

Kosharskyy

Vydyanathan

Zhang

et al. 2015

J Pharmacol Exp Ther

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We have previously shown that 2-acetylcyclopentanone (2-ACP), an enolate-forming 1,3-dicarbonyl compound, provides protection in cell culture and animal models of oxidative stress. The pathophysiology of ischemia-reperfusion injury (IRI) involves oxidative stress, and, therefore, we determined the ability of 2-ACP to prevent this injury in a rat liver model. IRI was induced by clamping the portal vasculature for 45 minutes (ischemia phase), followed by recirculation for 180 minutes (reperfusion phase). This sequence was associated with substantial derangement of plasma liver enzyme activities, histopathological indices, and markers of oxidative stress. The 2-ACP (0.80-2.40 mmol/kg), administered by intraperitoneal injection 10 minutes prior to reperfusion, provided dose-dependent cytoprotection, as indicated by normalization of the IRI-altered liver histologic and biochemical parameters. The 2-ACP (2.40 mmol/kg) was also hepatoprotective when injected before clamping the circulation (ischemia phase). In contrast, an equimolar dose of N-acetylcysteine (2.40 mmol/kg) was not hepatoprotective when administered prior to reperfusion. Our studies to date suggest that during reperfusion the enolate nucleophile of 2-ACP limits the consequences of mitochondrialbased oxidative stress through scavenging unsaturated aldehyde electrophiles (e.g., acrolein) and chelation of metal ions that catalyze the free radical-generating Fenton reaction. The ability of 2-ACP to reduce IRI when injected prior to ischemia most likely reflects the short duration of this experimental phase (45 minutes) and favorable pharmacokinetics that maintain effective 2-ACP liver concentrations during subsequent reperfusion. These results provide evidence that 2-ACP or an analog might be useful in treating IRI and other conditions that have oxidative stress as a common molecular etiology.

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Section: Discussionmentioning

confidence: 99%

2-Acetylcyclopentanone, an Enolate-Forming 1,3-Dicarbonyl Compound, Is Cytoprotective in Warm Ischemia-Reperfusion Injury of Rat Liver

Kosharskyy

Vydyanathan

Zhang

et al. 2015

J Pharmacol Exp Ther

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“…Sang et al demonstrated that toxic doses of EGCG [200 and 400 mg/kg intraperitoneal (ip)] resulted in the formation of two cysteine conjugates of EGCG (EGCG-2′-cysteine and EGCG-2″-cysteine) and proposed that these conjugates arise from the formation of an EGCG quinone, which then reacts with the sulphydryl group on cysteine and likely with other cysteine-containing molecules such as GSH [56]. Moreover, treatment of lung tumor-bearing nude mice with daily injections of 40 mg/kg ip EGCG for 40 days resulted in increased expression of phosphorylated histone 2AX (a marker of DNA damage) and metallothionein (a marker of response to oxidative stress) in the liver and tumors relative to vehicle-treated mice [57].…”

Section: Discussionmentioning

confidence: 99%

Hepatotoxicity from green tea: a review of the literature and two unpublished cases

Mazzanti

Menniti‐Ippolito²,

Moro

et al. 2009

Eur J Clin Pharmacol

351

251

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Purpose To review the current literature on suspected green tea-related hepatic reactions and to describe two new cases reported within the framework of the Italian surveillance system of natural health products. Results A literature search of publication between 1999 and October 2008 retrieved 34 cases of hepatitis. Histological examination of the liver revealed inflammatory reactions, cholestasis, occasional steatosis, and necrosis. A positive dechallenge was reported in 29 cases. There was one reported death. A positive rechallenge occurred in seven cases (20%). In the two new cases, the causality assessment was judged as "possible" according to the RUCAM score. Conclusions Our analysis of the published case reports suggests a causal association between green tea and liver damage. The hepatotoxicity is probably due to (-)-epigallocatechin gallate or its metabolites which, under particular conditions related to the patient's metabolism, can induce oxidative stress in the liver. In a few cases, toxicity related to concomitant medications could also be involved.

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“…En la tabla 1, se encuentran los resultados obtenidos en la caracterización cualitativa de los 3 extractos evaluados (M. lanceolata, S. sessiliflora y C.leptostachyus); en las 3 especies se determinó la presencia de metabolitos como polifenoles, taninos, flavonoides y fenilpropanoides, entre otros. La presencia de compuestos de naturaleza polifenólica en las 3 plantas fue abundante, destacando el contenido de estos metabolitos en M. lanceolata, estos compuestos se destacan por generar defensa ante diversos factores como la radicación UV, ataque de animales, de hongos y bacterias (Cooper-Driver, et al, 2007); sin dejar de mencionar que han sido reportados en literatura científica como unos de los principios activos más importante para la estabilización de radicales (Lambert, et al, 2007;Cadenas, 2000).…”

Section: Resultados Y Discusiónunclassified

Acción antioxidante conjunta de extractos etanólicos de Mollinedia lanceolata, Croton leptostachyus y Siparuna sessiliflora

Pérez-Jaramillo

Sánchez-Peralta

Arango

et al. 2017

Rev. Acad. Colomb. Cienc. Ex. Fis. Nat.

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ResumenEn los últimos años el daño oxidativo se ha detectado en enfermedades como el cáncer, la diabetes y el Alzheimer, entre otras. Como una alternativa para la prevención y tratamiento de tales enfermedades, se ha propuesto el consumo de antioxidantes, especialmente de fuentes vegetales; sin embargo, se ha estudiado poco el efecto de las mezclas de compuestos de naturaleza antioxidante o de matrices que los contienen. En este trabajo se evaluó el potencial antioxidante de extractos y mezclas de Mollinedia lanceolata (Monimiaceae), Siparuna sessiliflora (Siparunaceae) y Croton leptostachyus (Euphorbiaceae). Se prepararon extractos etanólicos crudos de las tres plantas previamente caracterizados mediante procedimientos de fitoquímmica. Se hicieron pruebas antioxidantes indirectas con el radical 1,1-difenil-2-picrilhidracilo (DPPH) y el catión del ácido 2,2'-azino-bis 3-etilbenzotiazolina-6-sulfónico (ABTS), se determinaron las concentraciones de inhibición media (CI 50 ) usadas como base para la preparación de mezclas en una proporción de uno a uno con todos los extractos y se evaluó de nuevo su actividad antioxidante y antihemolítica, así como su índice de combinación con el programa de acceso libre CompuSyn. En los especímenes de estudio se hallaron polifenoles, taninos, flavonoides, terpenos, esteroides y alcaloides. El extracto más activo en la estabilización del radical DPPH fue el de C. leptostachyus (CI 50 = 53,5 ± 1,1 mg/l) y en la del ABTS, el de M. lanceolata (CI 50 = 128,8 ± 0,9 mg/l). Todas las mezclas actuaron de manera sinérgica para estabilizar el DPPH con índices de combinación (IC) mayores de uno, en tanto que en el caso del ABTS las mezclas fueron antagónicas (IC>1), excepto la de M. lanceolata y S. sessiliflora (IC<1). Ninguno de los extractos presentó efecto antihemolítico manifestado en mayores tasas de hemólisis, especialmente en las mezclas. © 2017. Acad. Colomb. Cienc. Ex. Fis. Nat.Palabras clave: Actividad antioxidante; Extractos vegetales; Acción conjunta; Sinergismo; Antagonismo; Monimiaceae; Euphorbiaceae; Siparunaceae. Joint antioxidant action of ethanolic extracts of Mollinedia lanceolata, Croton leptostachyus and Siparuna sessiliflora AbstractIn recent years, oxidative damage has been associated with diseases such as cancer, diabetes and Alzheimer, among others. The consumption of antioxidants, especially from vegetable sources, has been proposed as an alternative for prevention and treatment; however, few studies have been conducted on the effect of mixtures of antioxidant compounds or matrices that include them. In this study we used crude extracts and mixtures of extracts from Mollinedia lanceolata, Siparuna sessiliflora and Croton leptostachyus. We prepared crude ethanolic extracts from the three plants previously characterized with phytochemical procedures. We performed indirect antioxidant tests with the DPPH and ABTS radicals, we determine the various IC 50 used as the basis for preparing 1:1 mixtures with all the extracts and we reassess their antioxidant and antiemolitic ...

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Possible Controversy over Dietary Polyphenols: Benefits vs Risks

Cited by 221 publications

References 25 publications

2-Acetylcyclopentanone, an Enolate-Forming 1,3-Dicarbonyl Compound, Is Cytoprotective in Warm Ischemia-Reperfusion Injury of Rat Liver

2-Acetylcyclopentanone, an Enolate-Forming 1,3-Dicarbonyl Compound, Is Cytoprotective in Warm Ischemia-Reperfusion Injury of Rat Liver

Hepatotoxicity from green tea: a review of the literature and two unpublished cases

Acción antioxidante conjunta de extractos etanólicos de Mollinedia lanceolata, Croton leptostachyus y Siparuna sessiliflora

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