Epigallocatechin gallate potentially attenuates Fluoride induced oxidative stress mediated cardiotoxicity and dyslipidemia in rats

Catechins and other phenolic compounds in herb of eight Ephedra species in comparison to Camellia sinensis

Using HPLC-DAD the presence of catechin, epicatechin, quercetin, kaempferol and protocatehuic acid was analysed in herb extracts of eight Ephedra species (Ephedra sinica, Ephedra major, Ephedra chilensis, Ephedra ciliata, Ephedra foeminea, Ephedra equisetina, Ephedra gerardiana and Ephedra distachya). For comparison purposes, the same phenolics were determined in Camellia sinensis herb, which is a common source of catechins and a medicinal plant with valuable antioxidant properties. The catechin content in Ephedra spp. ranged between 0.83 mg/g d.w.- 8.77 mg/g d.w., while the epicatechin content was between 0.11 mg/g d.w.- 3.38 mg/g d.w. In comparison to black tea, Ephedra major, Ephedra distachya and Ephedra equisetina had a higher catechin content. The selected Ephedra spp. are rich in catechins and the obtained results serve as the chemical rationale for the anti-inflammatory, antioxidant and anti-proliferative activities of Ephedra that are currently being investigated.

Longitudinal associations between early-life fluoride exposures and cardiometabolic outcomes in school-aged children

BACKGROUND/AIM

Fluoride is a natural mineral present in food, water, and dental products, constituting ubiquitous long-term exposure in early childhood and across the lifespan. Experimental evidence shows fluoride-induced lipid disturbances with potential implications for cardiometabolic health. However, epidemiological studies are scarce. For the first time, we evaluated associations between repeated fluoride measures and cardiometabolic outcomes in children.

METHODS

We studied ∼ 500 Mexican children from the Programming Research in Obesity, Growth, Environment and Social Stressors (PROGRESS) cohort with measurements on urinary fluoride at age 4, and dietary fluoride at ages 4, 6, and 8 years approximately. We used covariate-adjusted linear mixed-effects and linear regression models to assess fluoride associations with multiple cardiometabolic outcomes (ages 4-8): lipids (total cholesterol, HDL, LDL, and triglycerides), glucose, HbA1c, adipokines (leptin and adiponectin), body fat, and age- and sex-specific z-scores of body mass index (zBMI), waist circumference, and blood pressure.

RESULTS

Dietary fluoride intake at age 4 was associated with annual increases in triglycerides [β per-fluoride-doubling = 2.02 (95 % CI: 0.37, 3.69)], cholesterol [β = 1.46 (95 % CI: 0.52, 2.39)], HDL [β = 0.39 (95 % CI: 0.02, 0.76)], LDL [β = 0.87 (95 % CI: 0.02, 1.71)], and HbA1c [β = 0.76 (95 % CI: 0.28, 1.24)], and decreased leptin [β = -3.58 (95 % CI: -6.34, -0.75)] between the ages 4 and 8. In cross-sectional analyses at age 8, higher tertiles of fluoride exposure were associated with increases in zBMI, triglycerides, glucose, and leptin (p-tertile trend < 0.05). Stronger associations were observed in boys at year 8 and in girls prior to year 8 (p-sex interaction < 0.05). Fewer but consistent associations were observed for urinary fluoride at age 4, indicating increased annual changes in HDL and HbA1c with higher fluoride levels.

CONCLUSION

Dietary fluoride exposures in early- and mid-childhood were associated with adverse cardiometabolic outcomes in school-aged children. Further research is needed to elucidate whether these associations persist at later ages.

Protective effects of cardamom aqueous extract against tamoxifen-induced pancreatic injury in female rats

Tamoxifen (TAM) is a commonly used drug for breast cancer treatment. Although effective, TAM has deleterious effects on many organs. The toxic effects of TAM on the pancreas and the underlying mechanisms however, have not fully investigated. In the present study, we investigated the effects of TAM on the pancreatic tissue in female rats. We also examined whether cardamom aqueous extract (CAE) protects against TAM-induced pancreatic injury. TAM-intoxicated rats were injected with 45 mg/kg of TAM for 10 days, whereas rats in the CAE-treated group were administered 10 mL/kg of CAE for 20 days, starting 10 days prior to TAM administration. Treatment with TAM resulted in severe degeneration of the pancreatic acini and marked increases in the serum levels of pancreatic lipase, α-amylase, glucose, fatty acids and triglycerides along with decreased insulin serum levels. TAM led to oxidative stress as evident from a significant increase in the pancreatic levels of lipid peroxides and nitric oxide along with the depletion of reduced glutathione, glutathione peroxidase, and superoxide dismutase. Moreover, inflammation was indicated by a significant increase in tumor necrosis factor-α and interleukin-6 levels, enhanced expression of the macrophage recruitment marker; CD68 as well as up-regulated protein levels of toll-like receptor 4 and nuclear factor kappa B and increased p-p38/MAPK ratio; which are important signals in the production of inflammatory cytokines. TAM also markedly increased the pancreatic levels of caspase-3 and BAX reflecting its apoptotic effects. The CAE treatment ameliorated all the biochemical and histological changes induced by TAM. The present study revealed, for the first time, that TAM has toxic effects on the pancreatic tissue through oxidative stress, inflammation and apoptotic effects. The present study also provides evidence that CAE exerts cytoprotective effects against these deleterious effects induced by TAM in the pancreatic tissue.

Supplementary Information

The online version contains supplementary material available at 10.1007/s43188-023-00198-w.

Necessity to Pay Attention to the Effects of Low Fluoride on Human Health: an Overview of Skeletal and Non-skeletal Damages in Epidemiologic Investigations and Laboratory Studies

Due to the implementation of water improvement and fluoride reduction plans supported by central and local governments in recent years, areas with high fluoride exposure are being gradually decreased. Therefore, it is of practical importance to study the effect of low fluoride on human health. Epidemiologic investigations and in vivo and in vitro studies based on low fluoride have also confirmed that fluoride not only causes skeletal damage, such as dental fluorosis, but also causes non-skeletal damage involving the cardiovascular system, nervous system, hepatic and renal function, reproductive system, thyroid function, blood glucose homeostasis, and the immune system. This article summarizes the effects of low fluoride on human and animal skeletal and non-skeletal systems. A preliminary exploration of corresponding mechanisms that will help to fully understand the harm of low fluoride on human health was undertaken to provide the basis for establishing new water fluoride standards and help to implement individual guidance.

Catechins: Protective mechanism of antioxidant stress in atherosclerosis

Tea has long been valued for its health benefits, especially its potential to prevent and treat atherosclerosis (AS). Abnormal lipid metabolism and oxidative stress are major factors that contribute to the development of AS. Tea, which originated in China, is believed to help prevent AS. Research has shown that tea is rich in catechins, which is considered a potential source of natural antioxidants. Catechins are the most abundant antioxidants in green tea, and are considered to be the main compound responsible for tea's antioxidant activity. The antioxidant properties of catechins are largely dependent on the structure of molecules, and the number and location of hydroxyl groups or their substituents. As an exogenous antioxidant, catechins can effectively eliminate lipid peroxidation products. They can also play an antioxidant role indirectly by activating the endogenous antioxidant system by regulating enzyme activity and signaling pathways. In this review, we summarized the preventive effect of catechin in AS, and emphasized that improving the antioxidant effect and lipid metabolism disorders of catechins is the key to managing AS.

Association of maternal urinary fluoride concentrations during pregnancy with size at birth and the potential mediation effect by maternal thyroid hormones: The Swedish NICE birth cohort

BACKGROUND

Observational studies have indicated that elevated maternal fluoride exposure during pregnancy may impair child neurodevelopment but a potential impact on birth outcomes is understudied.

OBJECTIVES

To evaluate the impact of gestational fluoride exposure on birth outcomes (birth size and gestational age at birth) and to assess the potential mediating role of maternal thyroid hormones.

METHODS

We studied 583 mother-child dyads in the NICE cohort in northern Sweden. Maternal fluoride exposure was assessed by measuring urinary concentrations at late pregnancy (median: 29th gestational week) using an ion selective electrode. Plasma levels of free and total thyroxine (fT4, tT4) and triiodothyronine (fT3, tT3), and thyroid stimulating hormone (TSH) were measured with electrochemiluminescence immunoassays. The infant's weight, length, head circumference, and gestational age at birth were extracted from hospital records.

RESULTS

Median urinary fluoride concentration was 0.71 mg/L (5th-95th percentile 0.31-1.9 mg/L; specific gravity adjusted). In multivariable-adjusted regression models, every 1 mg/L increase of maternal urinary fluoride was associated with a mean increase in birth weight by 84 g (95%CI: 30, 138), length by 0.41 cm (95%CI: 0.18, 0.65), head circumference by 0.3 cm (95%CI: 0.1, 0.4), and with increased odds of being born large for gestational age (OR = 1.39, 95%CI: 1.03, 1.89). Every 1 mg/L increase of maternal urinary fluoride was also associated with a mean increase of the plasma fT3:fT4 ratio (B = 0.007, 95%CI: 0.000, 0.014), but not with the hormones or TSH. In mediation analyses, the maternal fT3:fT4 ratio did not explain the urinary fluoride-birth size relationships.

DISCUSSION

Gestational urinary fluoride concentrations were associated with increased size at birth and even with increased odds of being born large for gestational age. The fluoride-related associations with increased size at birth were not explained by changes in maternal thyroid hormone levels.

Antioxidant Phytochemicals for the Prevention of Fluoride-Induced Oxidative Stress and Apoptosis: a Review

Fluorosis is a major public health problem globally. The non-availability of specific treatment and the irreversible nature of dental and skeletal lesions poses a challenge in the management of fluorosis. Oxidative stress is known to be one of the most important mechanisms of fluoride toxicity. Fluoride promotes the accumulation of reactive oxygen species by inhibiting the activity of antioxidant enzymes, resulting in the excessive production of reactive oxygen species at the cellular level which further leads to activation of cell death processes such as apoptosis. Phytochemicals that act as antioxidants have the potential to protect cells from oxidative stress. Evidence confirms that clinical symptoms of fluorosis can be mitigated to some extent or prevented by long-term intake of antioxidants and plant products. The primary purpose of this review is to examine recent findings that focus on the amelioration of fluoride-induced oxidative stress and apoptosis by natural and synthetic phytochemicals and their molecular mechanisms of action.

Cadmium exposure induces cardiac glucometabolic dysregulation and lipid accumulation independent of pyruvate dehydrogenase activity

CONTEXT

Suppressed glucose metabolism, elevated fatty acid metabolism and lipid deposition within myocardial cells are the key pathological features of diabetic cardiomyopathy. Studies have associated cadmium exposure with metabolic disturbances.

OBJECTIVE

To examine the effects of cadmium exposure on cardiac glucose homeostasis and lipid accumulation in male Wistar rats.

METHODS

Male Wistar rats were treated for 21 days as (n = 5): Control, cadmium chloride Cd5 (5 mg/kg, p.o.), cadmium chloride Cd30 (30 mg/kg, p.o).

RESULTS

The fasting serum insulin level in this study decreased significantly. Pyruvate and hexokinase activity reduced significantly in the Cd5 group while no significant change in lactate and glycogen levels. The activity of pyruvate dehydrogenase enzyme significantly increased with an increasing dosage of cadmium. The free fatty acid, total cholesterol and triglyceride levels in the heart increased significantly with increasing dosage of cadmium when compared with the control. Lipoprotein lipase activity in the heart showed no difference in the Cd5 group but a reduction in the activity in the Cd30 group was observed.

CONCLUSION

This study indicates that cadmium exposure interferes with cardiac substrate handling resulting in impaired glucometabolic regulation and lipid accumulation which could reduce cardiac efficiency.

Co-exposure to fluoride and arsenic disrupts intestinal flora balance and induces testicular autophagy in offspring rats

While numerous studies have shown that fluoride or arsenic exposure may damage the reproductive system, there are few reports of co-exposure to fluoride and arsenic. In addition, the literature on autophagy and intestinal flora composition in reproductive toxicity studies of co-exposure to fluoride and arsenic is insufficient. In this study, we developed a rat model of fluoride and arsenic exposure via drinking water from pre-pregnancy to 90 days postnatal. Sprague-Dawley rats were randomly divided into sterile water control group, fluoride group (100 mg/L NaF), arsenic group (50 mg/L NaAsO₂) and combined exposure group (100 mg/L NaF+50 mg/L NaAsO₂). Our results showed that fluoride and arsenic exposure caused a reduction in testicular weight and significant pathological damage to tissue. We found that the levels of follicle-stimulating hormone, luteinizing hormone, and testosterone were reduced to varying degrees. Meanwhile experiments showed that fluoride and arsenic exposure can modulate autophagic flux, causing increased levels of Beclin1 and LC3 expression and decreased p62 expression. Analogously, by performing 16S sequencing of rat feces, we found 24 enterobacterial genera that differed significantly among the groups. Furthermore, the flora associated with testicular injury were identified by correlation analysis of hormonal indices and autophagy alterations with intestinal flora composition at the genus level, respectively. In summary, our study shows that fluoride and arsenic co-exposure alters autophagic flux in the testis, causes testicular injury, and reveals an association between altered intestinal flora composition and testicular injury.

The therapeutic effects of Prunella vulgaris against fluoride-induced oxidative damage by using the metabolomics method

Fluoride is considered as one of the most ubiquitous environmental pollutants. Numerous studies have linked reactive oxygen species (ROS)-dependent oxidative damage with fluoride intoxication, which could be prevented by antioxidants. However, the metabolomic changes induced by ROS disruptions in fluoride intoxication are yet unknown. The present study aimed to provide novel mechanistic insights into the fluoride-induced oxidative damage and to investigate the potential protective effects of ethanolic extract of Prunella vulgaris (natural antioxidant, PV) against fluoride-induced oxidative damage. The serum biochemical indicators related to fluoride-induced oxidative damage, such as lipid peroxidation parameter, inflammation and marker enzymes in the liver increased significantly in the fluoride-treated group, while antioxidant enzymes were decreased. However, PV treatment restored the level of these biochemical indicators, indicating satisfactory antioxidant, anti-inflammatory, and hepatoprotective potential of PV. The metabolomics analysis in the serum was performed by liquid chromatography-mass spectroscopy, whereas the fluoride treatment caused severe metabolic disorders in rats, which could be improved by PV. The differential metabolites screened by multivariate analysis after fluoride and PV treatment, were organic acids, fatty acids, and lipids. These differential metabolites represented disorders of glyoxylate and dicarboxylate metabolism and the citrate cycle (TCA) according to metabolic pathway analysis in fluoride treatment rats. Interestingly, the result of metabolic pathway analysis of post-treatment with PV was consistent with that of fluoride treatment, indicating that the energy metabolism plays a major role in the progress of fluoride-induced oxidative damage, as well as the therapeutic effect of PV. These findings provided a theoretical basis for understanding the mechanism underlying metabolic disorders of fluoride toxicity and the effect of PV.

Crocin ameliorates arsenic trioxide‑induced cardiotoxicity via Keap1-Nrf2/HO-1 pathway: Reducing oxidative stress, inflammation, and apoptosis

Arsenic trioxide (ATO) is an excellent therapy for acute promyelocytic leukemia; however, its use is limited due to its cardiotoxicity. Crocin (CRO) possesses abundant pharmacological and biological properties, including antioxidant, anti-inflammatory, and anti-apoptotic. This study examined the cardioprotective effects of crocin and explored their mechanistic involvement in ATO-induced cardiotoxicity. Forty-eight male rats were treated with ATO to induce cardiotoxicity. In combination with ATO, CRO were given to evaluate its cardioprotection. The results demonstrated that CRO administration not only diminished QTc prolongation, myocardial enzymes and Troponin T levels but also improved histopathological results. CRO administration reduced reactive oxygen species generation. However, the CRO administration caused an increase in glutathione, superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase and total sulphydryl levels and a decrease in malondialdehyde content, gamma glutamyl transferase and lipid hydroperoxides levels and proinflammatory cytokines. Importantly, immunohistochemical analysis, real time PCR and western blotting showed a reduction in Caspase-3 and Bcl-2-associated X protein expressions and enhancement of B cell lymphoma-2 expression. Real time PCR and western blotting showed a reduction in proinflammatory cytokines. Moreover, CRO caused an activation in nuclear factor erythroid-2 related factor 2, leading to enhanced Kelch-like ECH-associated protein 1, heme oxygenase-1 and nicotinamide adenine dinucleotide quinone dehydrogenase 1 expressions involved in Nrf2 signaling during ATO-induced cardiotoxicity. CRO was shown to ameliorate ATO-induced cardiotoxicity. The mechanisms for CRO amelioration of cardiotoxicity due to inflammation, oxidative damage, and apoptosis may occur via an up-regulated Keap1-Nrf2/HO-1 signaling pathway.

Mitochondrial Dysfunction in Diabetic Cardiomyopathy: The Possible Therapeutic Roles of Phenolic Acids

As the powerhouse of the cells, mitochondria play a very important role in ensuring that cells continue to function. Mitochondrial dysfunction is one of the main factors contributing to the development of cardiomyopathy in diabetes mellitus. In early development of diabetic cardiomyopathy (DCM), patients present with myocardial fibrosis, dysfunctional remodeling and diastolic dysfunction, which later develop into systolic dysfunction and eventually heart failure. Cardiac mitochondrial dysfunction has been implicated in the development and progression of DCM. Thus, it is important to develop novel therapeutics in order to prevent the progression of DCM, especially by targeting mitochondrial dysfunction. To date, a number of studies have reported the potential of phenolic acids in exerting the cardioprotective effect by combating mitochondrial dysfunction, implicating its potential to be adopted in DCM therapies. Therefore, the aim of this review is to provide a concise overview of mitochondrial dysfunction in the development of DCM and the potential role of phenolic acids in combating cardiac mitochondrial dysfunction. Such information can be used for future development of phenolic acids as means of treating DCM by alleviating the cardiac mitochondrial dysfunction.

Argan oil ameliorates sodium fluoride-induced renal damage via inhibiting oxidative damage, inflammation, and intermediate filament protein expression in male rats

Fluoride is widely distributed in the environment and has been associated with the development of different health hazards in animals and humans. Argan oil (AO) is a natural vegetable oil with various beneficial pharmacological effects. This study was designed to investigate the potential protective effect of AO supplementation as pre-treatment or co-treatment on sodium fluoride (NaF)-induced nephrotoxicity in rats. Male Sprague Dawley rats (n = 50) were randomly assigned to one of five equal groups: control group, AO-treated group (6 ml/kg b.wt.), NaF-treated group (20 mg/kg b.wt.), pre-treated group, and co-treated group. All rats were daily administered by oral gavage for duration of 30 days. The results showed that AO administration significantly improved renal function and antioxidant status and decreased the lipid peroxidation in NaF-treated rats. Additionally, AO normalized the renal levels of inflammatory markers and mRNA expression level of the intermediate filament protein genes, indicating NaF-induced podocyte damage was ameliorated. Histopathological evaluation of the kidney confirmed the before mentioned biochemical results. AO counteracted the nephrotoxic effects of NaF in rats particularly at co-exposure. These results concluded that AO administration exhibited a significant nephroprotective effect against renal injury induced by NaF in rats.

A review for physiological activities of EGCG and the role in improving fertility in humans/mammals

Epigallocatechin-3-gallate (EGCG) is a secondary metabolite in green tea, which has various physiological activities, including antioxidant, antitumor, and antiviral activities. Studies have shown that EGCG has a preventive effect on infertility by protecting germ cells and oocytes from damage. EGCG functions mainly through the regulation of ROS (reactive oxygen species) levels, which affect the expression of catalase (CAT), superoxide dismutase 1(SOD1), superoxide dismutase 2(SOD2), and glutathione peroxidase (GPx), has positive influence on other enzyme activities in germ cells and oocytes, and actively alters antioxidant activities. These enzymes above can inhibit the activation of extracellular signal-regulated proteins (Erk), induce apoptosis, and control the production of ROS in tissue cells. Here, we present a comprehensive overview of the mechanisms underlying the main physiological activities of EGCG, including antioxidant, antitumor, and antiviral activities, and their potential roles in male and female reproductive systems and fertility. This paper discusses the mechanisms by which EGCG retards the infertility of germ cells and oocytes and provides a supportive recommendation for improving fertility in humans and animals. We hope it will provide useful references for related research in mammalian reproduction.

The Pharmacological Activity of Camellia sinensis (‎L.‎) ‎Kuntze‎ on Metabolic and Endocrine Disorders: A Systematic Review

Tea made from Camellia sinensis leaves is one of the most consumed beverages worldwide. This systematic review aims to update Camellia sinensis pharmacological activity on metabolic and endocrine disorders. Inclusion criteria were preclinical and clinical studies of tea extracts and isolated compounds on osteoporosis, hypertension, diabetes, metabolic syndrome, hypercholesterolemia, and obesity written in English between 2014 and 2019 and published in Pubmed, Science Direct, and Scopus. From a total of 1384 studies, 80 reports met inclusion criteria. Most papers were published in 2015 (29.3%) and 2017 (20.6%), conducted in China (28.75%), US (12.5%), and South Korea (10%) and carried out with extracts (67.5%, especially green tea) and isolated compounds (41.25%, especially epigallocatechin gallate). Most pharmacological studies were in vitro and in vivo studies focused on diabetes and obesity. Clinical trials, although they have demonstrated promising results, are very limited. Future research should be aimed at providing more clinical evidence on less studied pathologies such as osteoporosis, hypertension, and metabolic syndrome. Given the close relationship among all endocrine disorders, it would be of interest to find a standard dose of tea or their bioactive constituents that would be beneficial for all of them.

Low-to-moderate fluoride exposure in relation to overweight and obesity among school-age children in China

High fluoride exposure has been related to harmful health effects, but the impacts of low-to-moderate fluoride on child growth and obesity-related outcomes remain unclear. We performed a large-scale cross-sectional study to examine the association between low-to-moderate fluoride in drinking water and anthropometric measures among Chinese school-age children. We recruited 2430 resident children 7-13 years of age, randomly from low-to-moderate fluorosis areas of Baodi District in Tianjin, China. We analyzed the fluoride contents in drinking water and urine samples using the national standardized ion selective electrode method. Multivariable linear and logistic analyses were used to assess the relationships between fluoride exposure and age- and sex-standardized height, weight and body mass index (BMI) z-scores, and childhood overweight/obesity (BMI z-score > 1). In adjusted models, each log unit (roughly 10-fold) increase in urinary fluoride concentration was associated with a 0.136 unit increase in weight z-score (95% CI: 0.039, 0.233), a 0.186 unit increase in BMI z-score (95% CI: 0.058, 0.314), and a 1.304-fold increased odds of overweight/obesity (95% CI: 1.062, 1.602). These associations were stronger in girls than in boys (P_interaction = 0.016), and children of fathers with lower education levels were more vulnerable to fluoride (P_interaction = 0.056). Each log unit (roughly 10-fold) increase in water fluoride concentration was associated with a 0.129 unit increase in height z-score (95% CI: 0.005, 0.254), but not with other anthropometric measures. Our results suggest low-to-moderate fluoride exposure is associated with overweight and obesity in children. Gender and paternal education level may modify the relationship.

Epigallocatechin gallate attenuates arsenic induced genotoxicity via regulation of oxidative stress in balb/C mice

Arsenic is well known genotoxicant which causes the excessive generation of reactive oxygen species (ROS) and inhibition of antioxidant enzyme systems leading to cell damage through the activation of oxidative sensitive signaling pathways. Epigallocatechin gallate (EGCG), the main and active polyphenolic catechin present in green tea, has shown potent antioxidant, free radical scavenging and genoprotective activity in vivo. The present study attempted to investigate antioxidant and geno-protective efficacy of EGCG by regulating arsenic induced oxidative stress in mice. Animals received prophylactic and therapeutic treatments at two different doses (25 and 50 mg/kg b.wt.) of EGCG orally for 15 days and administered arsenic intraperitoneally at dose of 1.5 mg/kg b.wt (1/10th of LD₅₀) for 10 days. Arsenic intoxication revealed enhanced ROS production (114%) in lymphocytes; elevated levels of LPO (2-4 fold); reduced levels of hepato-renal antioxidants (approx. 45%) and augmented genomic fragmentation in hepato-renal tissues; increased chromosomal anomalies (78%) and micronucleation (21.93%) in bone marrow cells and comet tailing (25%) in lymphocytes of mice. Both pre and post treatments of EGCG decreased ROS production, restored lipid peroxidation (LPO) and reduced hepato-renal antioxidants levels, reduced the DNA fragmentation, number of chromosomal aberrations (CA), micronucleation (MN), and comet tailing but prophylactic treatment of 50 mg/kg b.wt was the most effective treatment in regulating arsenic induced oxidative stress. The effectiveness of this dose was furthermore validated by calculating the inhibitory index. Thus, results of present work empirically demonstrate free radical scavenging, anti-oxidative and genoprotective efficacy of EGCG against arsenic toxicity.

Effect of Duration of Exposure to Fluoride and Type of Diet on Lipid Parameters and De Novo Lipogenesis

The effect of duration of chronic treatment with fluoride (F, 50 mg/L as NaF) on the lipid profile, lipid droplets and triglycerides (TG) in liver was evaluated in mice with nonalcoholic fatty liver disease (NAFLD) previously induced by hyperlipidic diet and in animals fed normocaloric diet. In addition, the effect of F administered for a short period (20 days) was evaluated on de novo lipogenesis, by nuclear magnetic resonance. GRP78, Apo-E, and sterol regulatory element-binding protein (SREBP) were quantified by Western blotting. Our data indicate that F interferes in lipid metabolism and lipid droplets, having a different action depending on the exposure time and type of diet administered. F improved lipid parameters and reduced steatosis only when administered for a short period of time (up to 20 days) to animals fed normocaloric diet. However, when NAFLD was already installed, lipid parameters were only slightly improved at 20 days of treatment, but no effect was observed on the degree of steatosis. In addition, lipid profile was in general impaired when the animals were treated with F for 30 days, regardless of the diet. Moreover, F did not alter de novo lipogenesis in animals with installed NAFLD. Furthermore, hyperlipidic diet increased F accumulation in the body. GRP78 increased, while Apo-E and SREBP decreased in the F-treated groups. Our results provide new insights on how F affects lipid metabolism depending on the available energy source.

Pathophysiological mechanisms of diabetic cardiomyopathy and the therapeutic potential of epigallocatechin-3-gallate. Biomed Pharmacother. 2019;109:2155-2172. [PMID: 30551473 DOI: 10.1016/j.biopha.2018.11.086]

Cardiovascular complications are considered one of the leading causes of morbidity and mortality among diabetic patients. Diabetic cardiomyopathy (DCM) is a type of cardiovascular damage presents in diabetic patients independent of the coexistence of ischemic heart disease or hypertension. It is characterized by impaired diastolic relaxation time, myocardial dilatation and hypertrophy and reduced systolic and diastolic functions of the left ventricle. Molecular mechanisms underlying these pathological changes in the diabetic heart are most likely multifactorial and include, but not limited to, oxidative/nitrosative stress, increased advanced glycation end products, mitochondrial dysfunction, inflammation and cell death. The aim of this review is to address the major molecular mechanisms implicated in the pathogenesis of DCM. In addition, this review provides studies conducted to determine the pharmacological effects of (-)-epigallocatechin-3-gallate (EGCG), the major polyphenol in green tea, focusing on its therapeutic potential against the processes involved in the pathogenesis and progression of DCM. EGCG has been shown to exert several potential therapeutic properties both in vitro and in vivo. Given its therapeutic potential, EGCG might be a promising drug candidate to decrease the morbidity and mortality associated with DCM and other diabetes complications.

Effects of Supplemental Epigallocatechin Gallate in the Diet of Broilers Exposed to Fluoride Intoxication

We evaluated the effects of dietary epigallocatechin gallate (EGCG) on the performance, biochemical parameters, and liver histopathology of fluoride-intoxicated broiler chickens. In total, 160 1-day-old male broiler chicks (Ross PM3 strain) were collected and assigned to four groups (40 animals each), with four replicates. The control group received a basal diet; the F group received 800 mg/kg fluoride; the EGCG group received 400 mg/kg EGCG; and the EGCG+F group received 400 mg/kg EGCG and 800 mg/kg fluoride. The live weight (LW) of F-treated chicks was significantly lower than that of the controls. In the F-treated groups, feed intake (FI) and LW values were lower, but the feed conversion ratio (FCR) was higher than those of the controls. The ratio of heart weight to LW was found to be the highest in the F-treated groups. Alkaline phosphatase (ALP), aspartate aminotransferase (AST), and total oxidant status (TOS) levels in the F-treated groups were significantly higher, whereas the increase in total cholesterol levels was insignificant than those in the control group. In the EGCG+F group, AST, total cholesterol, and TOS levels decreased to a level comparable to those in the control group. Histopathological evaluation revealed that there were mild changes in the portal region in the EGCG+F group; additionally, there was an improvement in liver morphology in the EGCG+F group compared to that in the F group. Thus, EGCG has potent antioxidant and regenerative effects that can ameliorate the detrimental effects of fluoride toxicity on blood parameters and the liver.

Proposed mechanism for understanding the dose- and time-dependency of the effects of fluoride in the liver

Fluoride (F) can induce changes in the expression of several liver proteins. It is suggested that these changes are dose- and time-dependent. The objective of this study was to analyze the effect of different F concentrations and exposure times to this ion on the pattern of protein expression in the liver of rats. Thirt-six 21-day-old male Wistar rats were divided into 2 groups (n = 18) according to the treatment duration (20 or 60 days). Each of these groups was then divided into 3 subgroups (n = 6) according to the concentration of F administered in drinking water, as follows: 0 mg/L (control), 15 mg/L or 50 mg/L. After the experiment periods, the animals were anesthetized and the liver and blood were collected. F was analyzed in plasma and liver. Part of the liver was fixed for histological analysis. Liver proteins were extracted and prepared for quantitative label-free mass spectrometry analysis. F concentrations in plasma and liver were significantly higher in the group treated with 50 mg /L in comparison with control, regardless the time of exposure. Histological alterations in the liver were more evident in the subgroups treated for 20 days. The proteomic analysis revealed changes in proteins related to endoplasmic reticulum and mitochondrial oxidative stress, mitochondrial alteration, apoptosis and cellular respiration upon exposure to F. The results reinforce previous findings showing that the effects of F in the liver are dose- and time-dependent and provide the molecular basis for understanding the evolution of these effects.

Exposure to Ionizing Radiation Causes Endoplasmic Reticulum Stress in the Mouse Hippocampus

It is well known that ionizing radiation-induced toxicity to normal tissue has functional consequences in the brain. However, the underlying molecular alterations have yet to be elucidated. We have previously reported cognitive impairments with concomitant changes in dendritic complexity, spine density and inflammation in mice at 6-24 weeks postirradiation. The goal of this study was to determine whether metabolic changes in the mouse hippocampus after whole-body (4 Gy) or cranial (9 Gy) X-ray irradiation might trigger some of the incipient changes contributing to the persisting pathology in the radiation-injured brain. Metabolomic and lipidomic profiling of hippocampal tissue revealed that radiation induced dyslipidemia in mice at two days and two weeks postirradiation. Strikingly, significant changes were also observed in metabolites of the hexosamine biosynthesis pathway, a finding that was further confirmed using orthogonal methodologies. We hypothesize that these changes in hexosamine metabolism could induce endoplasmic reticulum stress and contribute to radiation-induced cognitive impairments. Taken together, our results show that molecular phenotyping is a valuable approach to identify potentially detrimental pathway perturbations that manifest significantly earlier than gross structural and functional changes in the irradiated brain.

Gallic Acid and Gallates in Human Health and Disease: Do Mitochondria Hold the Key to Success?

Gallic acid and gallate esters are widely used as dietary supplements or additives with clinical significances. Over the last few decades, a large number of publications have been reported stating the antioxidative, antiapoptotic, cardioprotective, neuroprotective, and anticancer properties of gallic acid and gallates, and mostly demonstrated their antioxidative or prooxidative properties influencing the reactive oxygen species (ROS) signaling networks. However, very little focus has been paid to clinical trials, and this restricted their use as a prescribed preventative supplement. Since mitochondria are the principal organelles responsible for ROS generation, we reviewed the existing literature of mitochondria-specific effects of gallates including ROS production, respiration, mitochondrial biogenesis, apoptosis, and the physico-chemical parameters affecting the outcome of gallate supplementation to various health scenarios such as cardiovascular diseases, neurodegeneration, hepatic ailments, or cancers. The major signaling pathways and the molecules targeted by gallic acid and its derivatives have also been discussed with emphasis on mitochondria as the target site. This review provides a better understanding of the effect of gallic acid and gallate esters on mitochondrial functions and in designing effective preventative measures against the onset of various diseases.

Protective role of epigallocatechin-3-gallate on arsenic induced testicular toxicity in Swiss albino mice

Arsenic, often referred to as the king of poisons is carcinogenic in humans and animals. It affects multiorgan systems including reproduction. The present study was undertaken to explore the protective role of green tea compound, epigallocatechin-3-gallate (EGCG) on arsenic induced testicular toxicity in Swiss albino mice. Thirty two adult male mice were randomly assigned to four groups (n=8). Group I served as control without test chemical. The group II received arsenic (200ppm) through drinking water, group III received only EGCG (20mg/kgb.wt., intraperitoneally, alternate days) and group IV was administered arsenic+EGCG for 40days. Factorial experimental design was employed to assess the treatment effect. The EGCG restored arsenic induced decrements in epididymal sperm concentration, kinematic attributes (total motility, rapid, progressive motile, fast progressive, VSL, VAP, VCL, BCF, LIN, WOB, STR and Type A), structutal membrane integrity, functional membrane integrity and mitochondrial membrane potential. As evidenced by the histoarchitectural studies, the EGCG reversed the deleterious effects of arsenic on testicular malondialdehyde (p<0.05) levels, reduced glutathione, antioxidative enzymes and spermatogenesis. Overall, the results suggest that EGCG reduces the testicular oxidative stress induced by arsenic poisoning and thereby protect the reproductive system.

Black Tea Source, Production, and Consumption: Assessment of Health Risks of Fluoride Intake in New Zealand

In countries with fluoridation of public water, it is imperative to determine other dietary sources of fluoride intake to reduce the public health risk of chronic exposure. New Zealand has one of the highest per capita consumption rates of black tea internationally and is one of the few countries to artificially fluoridate public water; yet no information is available to consumers on the fluoride levels in tea products. In this study, we determined the contribution of black tea as a source of dietary fluoride intake by measuring the fluoride content in 18 brands of commercially available products in New Zealand. Fluoride concentrations were measured by potentiometric method with a fluoride ion-selective electrode and the contribution of black tea to Adequate Intake (AI) and Tolerable Upper Intake Level (UL) was calculated for a range of consumption scenarios. We examined factors that influence the fluoride content in manufactured tea and tea infusions, as well as temporal changes in fluoride exposure from black tea. We review the international evidence regarding chronic fluoride intake and its association with chronic pain, arthritic disease, and musculoskeletal disorders and provide insights into possible association between fluoride intake and the high prevalence of these disorders in New Zealand.

Putative mechanisms of genotoxicity induced by fluoride: a comprehensive review

Genotoxicity is the ability of an agent to produce damage on the DNA molecule. Considering the strong evidence for a relationship between genetic damage and carcinogenesis, to elucidate the putative mechanisms of genotoxicity induced by fluoride are important to measure the degree of risk involved to human populations. The purpose of this article is to provide a comprehensive review on genotoxicity induced by fluoride on the basis of its mechanisms of action. In the last 10 years, all published data showed some evidence related to genotoxicity, which is due to mitochondrial disruption, oxidative stress, and cell cycle disturbances. However, this is an area that still requires a lot of investigation since the published data are not sufficient for clarifying the genotoxicity induced by fluoride. Certainly, the new information will be added to those already established for regulatory purposes as a safe way to promote oral healthcare and prevent oral carcinogenesis.

Sodium fluoride induces hypertension and cardiac complications through generation of reactive oxygen species and activation of nuclear factor kappa beta

Human exposure to sodium fluoride through its daily usage is almost inevitable. Cardiovascular and renal dysfunction has been associated with fluoride toxicity. Therefore, this study investigated the mechanism of action of sodium fluoride (NaF) induced hypertension and cardiovascular complications Forty male albino rats of an average of 10 rats per group were used. Group A received clean tap water. Toxicity was induced in Group B to D by administering graded doses of NaF through drinking water ad libitum for 10 days at 150 ppm, 300 ppm, and 600 ppm concentration respectively. Following administration of NaF, there was significant increase in systolic pressure, diastolic pressure and mean arterial pressure. Markers of oxidative stress; malondialdehyde, hydrogen peroxide, advance oxidation protein products, and protein carbonyl were significantly increased in dose-dependent pattern in the cardiac and renal tissues of rats together with significant decrease in the GST activity in NaF-treated rats compared to the control. Also serum markers of inflammation, cardiac, and renal damage including myeloperoxidase, xanthine oxidase, blood urea nitrogen, creatinine, Lactate dehydrogenase (LDH), and Creatinine kinase myocardial band (CK-MB) significantly increased indicating induction of oxidative stress, renal, and cardiac damage after exposure. Histopathology of the kidney and heart revealed aberrations in the histological architecture in NaF-treated rats. Also, immunohistochemistry showed higher expression of nuclear factor kappa beta (NF-kB) in the cardiac and renal tissues of rats administered NaF. Combining all, these results indicate NaF-induced hypertension through generation of reactive oxygen species and activation of renal and cardiac NF-kB expressions. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1089-1101, 2017.

Epigallocatechin-3-gallate attenuates cerebral cortex damage and promotes brain regeneration in acrylamide-treated rats

ACR increased the rate of nestin-positive cells implying that ACR caused cell damage, and EGCG decreased the rates of nestin-positive cells against ACR suggesting that EGCG may promote cell regeneration.

Effects of Epigallocatechin Gallate on Tert-Butyl Hydroperoxide-Induced Mitochondrial Dysfunction in Rat Liver Mitochondria and Hepatocytes

Epigallocatechin gallate (EGCG) is a green tea antioxidant with adverse effects on rat liver mitochondria and hepatocytes at high doses. Here, we assessed whether low doses of EGCG would protect these systems from damage induced by tert-butyl hydroperoxide (tBHP). Rat liver mitochondria or permeabilized rat hepatocytes were pretreated with EGCG and then exposed to tBHP. Oxygen consumption, mitochondrial membrane potential (MMP), and mitochondrial retention capacity for calcium were measured. First, 50 μM EGCG or 0.25 mM tBHP alone increased State 4 Complex I-driven respiration, thus demonstrating uncoupling effects; tBHP also inhibited State 3 ADP-stimulated respiration. Then, the coexposure to 0.25 mM tBHP and 50 μM EGCG induced a trend of further decline in the respiratory control ratio beyond that observed upon tBHP exposure alone. EGCG had no effect on MMP and no effect, in concentrations up to 50 μM, on mitochondrial calcium retention capacity. tBHP led to a decline in both MMP and mitochondrial retention capacity for calcium; these effects were not changed by pretreatment with EGCG. In addition, EGCG dose-dependently enhanced hydrogen peroxide formation in a cell- and mitochondria-free medium. Conclusion. Moderate nontoxic doses of EGCG were not able to protect rat liver mitochondria and hepatocytes from tBHP-induced mitochondrial dysfunction.

Protective effects of green tea and its main constituents against natural and chemical toxins: A comprehensive review

Toxins are natural or chemical poisonous substances with severe side effects on health. Humans are generally exposed by widespread toxic contaminations via air, soil, water, food, fruits and vegetables. Determining a critical antidote agent with extensive effects on different toxins is an ultimate goal for all toxicologists. Traditional medicine is currently perceived as a safe and natural approach against toxins. In this regard, we focused on the protective effects of green tea (Camellia sinensis) and its main components such as catechin, epicatechin, epicatechin gallate, gallocatechin, epigallocatechin and epigallocatechin gallate as a principal source of antioxidants against both natural and chemical toxins. This literate review demonstrates that protective effects of green tea and its constituents were mainly attributed to their anti-oxidative, radical scavenging, chelating, anti-apoptotic properties and modulating inflammatory responses. Although, some studies reveal they have protective effects by increasing toxin metabolism and neutralizing PLA₂, proteases, hyaluronidase and l-amino acid oxidase enzymes.

Fluoride Intensifies Hypercaloric Diet-Induced ER Oxidative Stress and Alters Lipid Metabolism

BACKGROUND

Here, we evaluated the relationship of diet and F-induced oxidative stress to lipid metabolism in the liver of rats eating normocaloric or hypercaloric diets for two time periods (20 or 60 days).

METHODS

Seventy-two 21-day-old Wistar rats were divided into 2 groups (n = 36) based on the type of diet they were eating; each of these groups was then further divided into another two groups (n = 18) based on the time periods of either 20 or 60 days, for a total of four groups. Each of these was divided into 3 subgroups (n = 6 animals/subgroup), dependent on the dose of F administered in the drinking water (0 mg/L(control), 15 mg/L or 50 mg/L). After the experimental period, blood samples and the liver were collected. Plasma samples were analyzed for HDL, cholesterol and triglycerides. Western blots were performed to probe for GRP78, Erp29, SOD2, Apo-E and SREBP in hepatic tissues.

RESULTS

As expected,the expression of target proteins involved in oxidative stress increased in the F-treated groups, especially in liver tissue obtained from animals eating a hypercaloric diet. Most changes in the lipid levels and pathological conditions were seen earlier in the time period, at day 20. The morphometric analyses showed a reduction in steatosis in groups on ahypercaloric diet and treated with 50 mg F/L compared to the control, while no changes were obtained in normocaloric-fed rats. Accordingly, plasma TG was reduced in the F-treated group. The reduced expression of Apo-E in a time- and diet-dependent pattern may account for the particular decrease in steatosis in hypercaloric-fed F-treated rats.

CONCLUSIONS

These results suggest that F changes liver lipid homeostasis, possibly because of the induction of oxidative stress, which seems to be higher in animals fed hypercaloric diets.

(-)-Epigallocatechin-3-gallate (EGCG) attenuates arsenic-induced cardiotoxicity in rats

Chronic arsenic exposure in drinking water is associated with the abnormalities of cardiac tissue. Excessive generation of ROS induced by arsenic has a central role in arsenic-induced cardiotoxicity. (-)-Epigallocatechin-3-gallate (EGCG), the most abundant polyphenol in green tea, possesses a potent antioxidant capacity and exhibits extensive pharmacological activities. This study was aim to evaluate the effect of EGCG on arsenic-induced cardiotoxicity in vivo and in vitro. Treatment with NaAsO2 seriously affected the morphology and ultrastructure of myocardium, and induced cardiac injuries, oxidative stress, intracellular calcium accumulation and apoptosis in rats. In consistent with in vivo study, the injuries, oxidative stress and apoptosis were also observed in NaAsO2-treated H9c2 cells. All of these effects induced by NaAsO2 were attenuated by EGCG. These results suggest EGCG could attenuate NaAsO2-induced cardiotoxicity, and the mechanism may involve its potent antioxidant capacity.

Establishment of drug delivery system nanocapsulated with an antioxidant (+)-catechin hydrate and sodium meta borate chelator against sodium fluoride induced oxidative stress in rats

Oxidative stress a major cause of fluoride induced toxicity and mitochondrial impairment in common in experimental rats during chronic exposure of fluoride. Attempts have been made in the present experiment to diminish oxidative damage, combined therapy with (+)-catechin hydrate (an antioxidant) and sodium meta borate (chelator) were used. Fluoride intoxication in rats was performed by using 13mg/kg NaF and both antioxidant CH and chelator SMB were used at a concentration of 8.98μM/kg body weight. Mixture of CH and SMB in free or in PLGA nanocapsule encapsulated form were prepared. The efficacies of those formulations were tested in combating free radical mediated oxidative insult produced by sodium fluoride (NaF). The amalgamated therapy used in this experiment was shown to reduce fluoride levels in liver, brain and kidney from 9.5, 5.5, 6.3μg/g to 4.6, 2, 2.6μg/g, respectively. Our result indicated that the combined chelator and antioxidant therapy in nanocapsulated drug delivery system could provide a projection in combating fluoride induced mitochondrial impairment in rat model.

Epigallocatechin gallate and mitochondria-A story of life and death

Epigallocatechin gallate (EGCG) is a flavonoid belonging to the chemical class of falvan-3-ols (catechins) esterified with gallic acid. It is the main catechin found in green tea (Camellia sinensis L.) accounting for about 50% of its total polyphenols. Extensive research performed in recent years has revealed that green tea demonstrates a wide range of positive biological activities against serious chronic diseases such as cardiovascular and neurodegenerative pathologies, cancer, metabolic syndrome and type 2 diabetes. These protective properties can be traced back to the potent antioxidant and anti-inflammatory activities of EGCG. Recent studies have suggested that it may exert its beneficial effects by modulating mitochondrial functions impacting mitochondrial biogenesis, bioenergetic control (ATP production and anabolism), alteration of the cell cycle, and mitochondria-related apoptosis. This review evaluates recent evidence on the ability of EGCG to exert critical influence on the above mentioned pathways.