ESR study on the structure–antioxidant activity relationship of tea catechins and their epimers

Guo, Qingbin; Zhao, Baolu; Shen, Shengrong; Hou, Jingbo; Hu, Jie; Xin, Wenjuan

doi:10.1016/s0304-4165(98)00168-8

Cited by 385 publications

(241 citation statements)

References 22 publications

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“…So in our present study demonstrate that, the activity of the MDA in malathion exposed group increased 2 fold compared with that of the control one, these finding is in accordance with Gultekin et al (2001) who reported that MDA values increased with increasing organophosphorous compounds concentration and incubation period (Ranjbar et al, 2005), may be due to Lipid peroxidation was seen in erythrocytes and liver of rats when exposed to malathion orally for 4 weeks at dose of 5,25 and 75 mg/Kg, respectively (Abdollahi et al, 2004) While in groups treated by malathion plus vitamine c or malathion plus green tea there were a significant decrease in MDA values in comparison with malathion group may be due to The protective effect of vitamin c over malathion toxicity is likely to be mediated via the inhibition of free radical generation and enhancement of free radical scavenging activity (Suna et al, 2010) and Green tea prevents the loss of lipophilic antioxidant α-tocopherol by repairing tocopheryl radicals and protection of the hydrophilic antioxidant ascorbate (Skryzdlewska et al, 2002). Therefore, it may decrease the concentration of lipid free radicals and terminate initiation and propagation of lipid peroxidation (Guo et al, 1999).…”

Section: Discussionmentioning

confidence: 99%

Protective Role of Vitamin C and Green Tea Extract on Malathion-Induced Hepatotoxicity and Nephrotoxicity in Rats

Elzoghby¹,

Hamoda²,

Aboubakr³

et al. 2014

American Journal of Pharmacology and Toxicology

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The present study was designed to determine the modulating effect of green tea and vitamin C against adverse effects of malathion. Animals were divided into four groups 5 rats /group). Group one was used as a control. Group two given malathion (50 mg/kg/day; 1/50 of the LD50 for four weeks). Group three and Group four were given malathion (50 mg/kg/day; 1/50 of the LD50 for four weeks) plus vitamin C (200 mg/kg/day) and plus green tea (36 mg/kg/day) respectively. At the end of the fourth week, the malathion-treated group had significantly lower Red Blood Cell count (RBCs), Hemoglobin concentration (Hb), Packed Cell Volume (PCV%) and leucocytes (WBCs) than the control group. Compared to the control group, the malathion-treated group had significantly higher serum Alkaline Phosphatase (ALP), Alanine aminotransferase (ALT), Aspartate aminotransferase (AST), Lactate Dehydrogenase (LDH), urea, creatinine and uric acid levels than the control group. The malathion treated rats also had significantly lower serum total protein, albumin and globulin levels than the control group, but the malathion plus vitamin C and malathion plus green tea groups did not differ from the control group in terms of these parameters. Moreover, concomitant vitamin C and green tea treatment significantly normalized, at least partially, all of the other hematological and biochemical parameters that were altered by malathion. Liver tissue homogenate in malathion treated group had lower Glutathione (GSH), Glutathione Peroxidase (GSH-PX) and Superoxide Dismutase (SOD) levels accompanied with higher level of Malondialdehyde (MDA) than the control group. Histopathological studies revealed that the malathion-treated, malathion plus vitamin C and malathion plus green tea treated groups exhibited histopathological changes in liver and kidney tissues, although some pathological features were only observed in the malathion-treated group. Thus, vitamin C and green tea can reduce malathion hepatotoxicity and nephrptoxicity.

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Section: Discussionmentioning

confidence: 99%

Protective Role of Vitamin C and Green Tea Extract on Malathion-Induced Hepatotoxicity and Nephrotoxicity in Rats

Elzoghby¹,

Hamoda²,

Aboubakr³

et al. 2014

American Journal of Pharmacology and Toxicology

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“…However, other mechanisms underlying the anti-obesity effects of GTCs cannot be excluded. GTCs can scavenge free radicals as antioxidants [28][29][30][31]. Moreover, oxidative stress is associated with adiposity in both human and mouse models of obesity [32][33][34].…”

Section: Discussionmentioning

confidence: 99%

Green tea catechins prevent obesity through modulation of peroxisome proliferator-activated receptors

Yan

Zhao

Bao

2013

Sci. China Life Sci.

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Epidemiological evidence and experimental studies suggest that drinking green tea is associated with a lower risk of obesity and related diseases. However, the mechanisms of these effects are not clear. In the present study, we investigated the antiobesity mechanisms of green tea catechins (GTCs) through modulation of peroxisome proliferator activated-receptor (PPAR) pathways in high-fat diet-induced obesity in rats. GTC supplementation significantly attenuated the increased body and liver weights and the elevated serum and liver triglyceride levels. Meanwhile, GTCs increased the PPARγ levels in subcutaneous white adipose tissue (SWAT) and decreased the PPAR levels in visceral white adipose tissue (VWAT). In addition, GTC treatment up-regulated the levels of PPARδ in SWAT, VWAT, and brown adipose tissue and increased the expression of genes involved in fatty acid oxidation in brown adipose tissue. Our results suggest that GTCs exert their anti-obesity mechanism in part by modulating PPAR signaling pathways. obesity, green tea catechins, peroxisome proliferator activated-receptors (PPARs), hyperlipidemia, metabolic syndrome

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“…However, after food processing (e.g., brewing green tea or roasting of cocoa beans) catechins could undergo conversion to suitable epimers, for example, epigallocatechin (ECG) to gallocatechin (GC) and EGCG to gallocatechin gallate (GCG) [10]. It was previously reported that stereochemistry could influence the radical scavenging activity of catechins [11]. However, Nanjo et al [12] observed no significant differences between the radical scavenging activities of catechin epimers; thus, the authors concluded that the scavenging potentials of catechins were not dependent on their steric structures.…”

Section: Mg In the Unitedmentioning

confidence: 99%

The influence of stereochemistry on the antioxidant properties of catechin epimers

Muzolf-Panek

Gliszczyńska‐Świgło

Szymusiak

et al. 2012

Eur Food Res Technol

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The influence of stereochemistry on the radical scavenging activity of catechins was investigated by studying the effect of pH on the antioxidant properties of catechin epimers. The difference in the pH-dependent Trolox equivalent antioxidant capacity (TEAC) profiles was observed only in case of gallocatechin gallate (GCG) and epigallocatechin gallate (EGCG), indicating the influence of steric structure on the TEAC antioxidant activity of these galloyl moiety-containing catechins. Based on comparison of the pH-dependent TEAC values to theoretically calculated parameters, including homolytic OH bond dissociation energy and ionization potential (IP) as well as theoretically predicted structures of the most stable monoanions of GCG and EGCG, it was concluded that due to steric hindrance in GCG molecule, the IP value of GCG monoanion increases reflecting lower radical scavenging capacity of GCG in comparison with EGCG. It results in the difference in the pH-dependent TEAC profiles of these two catechin epimers at pH above 3.5. This effect does not occur for other pairs of catechin epimers of this study.

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ESR study on the structure–antioxidant activity relationship of tea catechins and their epimers

Cited by 385 publications

References 22 publications

Protective Role of Vitamin C and Green Tea Extract on Malathion-Induced Hepatotoxicity and Nephrotoxicity in Rats

Protective Role of Vitamin C and Green Tea Extract on Malathion-Induced Hepatotoxicity and Nephrotoxicity in Rats

Green tea catechins prevent obesity through modulation of peroxisome proliferator-activated receptors

The influence of stereochemistry on the antioxidant properties of catechin epimers

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