Green tea catechins, alleviate hepatic lipidemic-oxidative injury in Wistar rats fed an atherogenic diet

Potential Role of Dietary Phenolic Compounds in the Prevention and Treatment of Rheumatoid Arthritis: Current Reports

Rheumatoid arthritis (RA) is a complex illness with both hereditary and environmental components. Globally, in 2019, 18 million people had RA. RA is characterized by persistent inflammation of the synovial membrane that lines the joints, cartilage loss, and bone erosion. Phenolic molecules are the most prevalent secondary metabolites in plants, with a diverse spectrum of biological actions that benefit functional meals and nutraceuticals. These compounds have received a lot of attention recently because they have antioxidant, anti-inflammatory, immunomodulatory, and anti-rheumatoid activity by modulating tumor necrosis factor, mitogen-activated protein kinase, nuclear factor kappa-light-chain-enhancer of activated B cells, and c-Jun N-terminal kinases, as well as other preventative properties. This article discusses dietary polyphenols, their pharmacological properties, and innovative delivery technologies for the treatment of RA, with a focus on their possible biological activities. Nonetheless, commercialization of polyphenols may be achievable only after confirming their safety profile and completing successful clinical trials.

Cilostazol attenuates cardiac oxidative stress and inflammation in hypercholesterolemic rats

Atherosclerosis is a multifactorial chronic disease associated with pro-inflammatory and pro-oxidative cardiovascular states. Cilostazol, a selective phosphodiesterase 3 inhibitor (PDE3), is clinically used in the treatment of intermittent claudication and secondary prevention of cerebral infarction. The aim of this study was to evaluate the cardioprotective effects of cilostazol and the molecular mechanisms involved in hypercholesterolemic rats. Male Wistar rats were divided into four groups: control group (C) and control + cilostazol group (C+CILO), that were fed a standard chow diet, and hypercholesterolemic diet group (HCD) and HCD + cilostazol (HCD+CILO) that were fed a hypercholesterolemic diet. Cilostazol treatment started after 30 days for C+CILO and HCD+CILO groups. Animals were administered cilostazol once a day for 15 days. Subsequently, serum and left ventricles were extracted for evaluation of lipid profile, inflammatory, and oxidative biomarkers. The HCD group displayed increased serum lipid levels, inflammatory cytokines production, and cardiac NF-kB protein expression and decreased cardiac Nrf2-mediated antioxidant activity. Conversely, the cilostazol treatment improved all these cardiac deleterious effects, inhibiting NF-kB activation and subsequently decreasing inflammatory mediators, reestablishing the antioxidant properties through Nrf2-mediated pathway, including increased SOD, GPx, and catalase expression. Taken together, our results indicated that cilostazol protects hypercholesterolemia-induced cardiac damage by molecular mechanisms targeting the crosstalk between Nrf2 induction and NF-kB inhibition in the heart.

Chrysophyllum albidum fruit ethanol extract ameliorates hyperglycaemia and elevated blood pressure in streptozotocin-induced diabetic rats through modulation of oxidative stress, NF-κB and PPAR-γ

Oxidative stress and inflammation arising from hyperglycaemia have been identified as important targets in mitigating hyperglycaemia-induced organ dysfunction in diabetics. Chrysophyllum albidum fruit is commonly consumed as fruit snacks because of its beneficial effects in diabetes management. This study aim to evaluate the protective mechanisms of Chrysophyllum albidum fruit extract (CAFE) in streptozotocin-induced rats involving attenuation of oxidative stress, nuclear factor-kappa B (NF-κB) and peroxisome proliferator-activated receptor-gamma (PPAR-γ). CAFE was investigated for in vitro antioxidant and alpha amylase inhibitory activity. Male Wistar rats were made diabetic by single intraperitoneal injection of streptozotocin (60 mg/kg). The rats were then treated with CAFE (100 and 200 mg/kg) and pioglitazone (10 mg/kg) for two weeks. Fasting blood sugar (FBS), blood pressure parameters, lipid profile, oxidative stress parameters, NF-κB and PPAR-γ were determined. The extract showed antioxidant and alpha amylase inhibitory activities. CAFE significantly reduced STZ-induced hyperglycaemia after 7 and 14 days of treatment. CAFE also reduced STZ-induced elevation of diastolic blood pressure and mean arterial pressure and as well reduced atherogenic index in diabetic rats. It significantly decreased lipid peroxidation but increased the enzymatic and non-enzymatic antioxidant markers in the plasma, liver, kidney and pancreas. The immunohistochemical analysis revealed that CAFE significantly decreased hepatic and renal tissues NF-κB while increasing PPAR-γ gene expressions. The results of this study collectively showed the protective effect of Chrysophyllum albidum fruit extract in streptozotocin-induced diabetic rats via modulation of oxidative stress and NF-κB/ PPAR-γ expressions.

Inosine, an endogenous purine nucleoside, avoids early stages of atherosclerosis development associated to eNOS activation and p38 MAPK/NF-kB inhibition in rats

Atherosclerosis is a multifactorial chronic disease, initiated by an endothelial dysfunction. Adenosine and its analogs can change a variety of inflammatory diseases and has shown important effects at different disease models. Inosine is a stable analogous of adenosine, but its effects in inflammatory diseases, like atherosclerosis, have not yet been studied. The aim of this study was to evaluate the pharmacological properties of inosine, administered sub chronically in a hypercholesterolemic model. Male Wistar rats were divided into four groups: control group (C) and control + inosine (C + INO) received standard chow, hypercholesterolemic diet group (HCD) and HCD + inosine (HCD + INO) were fed a hypercholesterolemic diet. At 31st experimentation day, the treatment with inosine was performed for C + INO and HCD + INO groups once daily in the last 15 days. We observed that the hypercholesterolemic diet promoted an increase in lipid levels and inflammatory cytokines production, while inosine treatment strongly decreased these effects. Additionally, HCD group presented a decrease in maximum relaxation acetylcholine induced and an increase in contractile response phenylephrine induced when compared to the control group, as well as it has presented an enhancement in collagen and ADP-induced platelet aggregation. On the other hand, inosine treatment promoted a decrease in contractile response to phenylephrine, evoked an improvement in endothelium-dependent vasorelaxant response and presented antiplatelet properties. Moreover, inosine activated eNOS and reduced p38 MAPK/NF-κB pathway in aortic tissues. Taken together, the present results indicate inosine as a potential drug for the treatment of cardiovascular disorders such as atherosclerosis.

Bio-evaluation of functional date bars using rats as model organism against hypercholesterolemia

Background

The present research project was designed to evaluate the cholesterol lowering potential of different date varieties including one exotic (Ajwa) and three Pakistani varieties (Aseel, Khudravi, Hallawi).

Methods

The albino rats were divided into six groups on the basis of different diets which includes, control having basal diet, high cholesterol high sucrose diet, high cholesterol high sucrose diet plus Khudravi dates, high cholesterol high sucrose diet plus Hallawi dates, high cholesterol high sucrose diet plus Aseel dates, high cholesterol high sucrose diet plus Ajwa dates to evaluate maximum cholesterol lowering potential of each date variety.

Results

The results showed that Hallawi and Ajwa have lower crude fiber content as 2.02 ± 0.03% and 2.43 ± 0.04% however, lowest crude fat content (0.26 ± 0.01%) was also observed in ajwa. Mineral profile depicted that sodium (9.50–18.00 mg/100 g) was found to be in lesser amount among all varieties whereas, higher amount of potassium (465.00 to 887.20 mg/100 g) depicted that it is suitable for people having hypertension. Higher amount of reducing sugar was also observed in ajwa (79.45 ± 1.22%) followed by Hallawi (77.68 ± 1.42%). Total phenolic contents were found higher in Aseel (291.36 mg/100 g) whereas, minimum was observed in Khudravi (232.64 mg/100 g). Furthermore, date varieties were also examined rat modeling to evaluate their maximum cholesterol lowering efficiency. Ajwa and Hallawi were observed to suppress the cholesterol efficiently as 110 mg/dL and 103 mg/dL respectively. On the basis of chemical profiling and other parameters, two date varieties Ajwa and Hallawi showed almost similar results and found to have maximum serum cholesterol, LDL and triglyceride reduction potential with good kidney and liver functions. Functional date bar was also developed by using Hallawi variety andsubjected to sensory evaluation.

Conclusion

In nutshell, Hallawi date variety was considered as better cholesterol lowering potential among other indigenous varieties and very close to Ajwa variety. So that Hallawi can be used to suppress the deadly effects of obesity and allied discrepancies particularly hypercholesterolemia.

Safety Evaluation of Green Tea Polyphenols Consumption in Middle-aged Ovariectomized Rat Model

This work evaluates chronic safety in middle-aged ovariectomized rats supplemented with different dosages of green tea polyphenols (GTP) in drinking water. The experiment used 6-mo-old sham (n = 39) and ovariectomized (OVX, n = 143) female rats. All sham (n = 39) and 39 of the OVX animals received no GTP treatment and their samples were collected for outcome measures at baseline, 3 mo, and 6 mo (n = 13 per group for each). The remaining OVX animals were randomized into 4 groups receiving 0.15%, 0.5%, 1%, and 1.5% (n = 26 for each) of GTP (wt/vol), respectively, in drinking water for 3 and 6 mo. No mortality or abnormal treatment-related findings in clinical observations or ophthalmologic examinations were noted. No treatment-related macroscopic or microscopic findings were noted for animals administered 1.5% GTP supplementation. Throughout the study, there was no difference in the body weight among all OVX groups. In all OVX groups, feed intake and water consumption significantly decreased with GTP dose throughout the study period. At 6 mo, GTP intake did not affect hematology, clinical chemistry, and urinalysis, except for phosphorus and blood urea nitrogen (increased), total cholesterol, lactate dehydrogenase, and urine pH (decreased). This study reveals that the no-observed-adverse-effect level (NOAEL) of GTP is 1.5% (wt/vol) in drinking water, the highest dose used in this study.

Green tea supplementation increases glutathione and plasma antioxidant capacity in adults with the metabolic syndrome

Green tea, a popular polyphenol-containing beverage, has been shown to alleviate clinical features of the metabolic syndrome. However, its effects in endogenous antioxidant biomarkers are not clearly understood. Thus, we tested the hypothesis that green tea supplementation will upregulate antioxidant parameters (enzymatic and nonenzymatic) in adults with the metabolic syndrome. Thirty-five obese participants with the metabolic syndrome were randomly assigned to receive one of the following for 8 weeks: green tea (4 cups per day), control (4 cups water per day), or green tea extract (2 capsules and 4 cups water per day). Blood samples and dietary information were collected at baseline (0 week) and 8 weeks of the study. Circulating carotenoids (α-carotene, β-carotene, lycopene) and tocopherols (α-tocopherol, γ-tocopherol) and trace elements were measured using high-performance liquid chromatography and inductively coupled plasma mass spectroscopy, respectively. Serum antioxidant enzymes (glutathione peroxidase, glutathione, catalase) and plasma antioxidant capacity were measured spectrophotometrically. Green tea beverage and green tea extract significantly increased plasma antioxidant capacity (1.5 to 2.3 μmol/L and 1.2 to 2.5 μmol/L, respectively; P < .05) and whole blood glutathione (1783 to 2395 μg/g hemoglobin and 1905 to 2751 μg/g hemoglobin, respectively; P < .05) vs controls at 8 weeks. No effects were noted in serum levels of carotenoids and tocopherols and glutathione peroxidase and catalase activities. Green tea extract significantly reduced plasma iron vs baseline (128 to 92 μg/dL, P < .02), whereas copper, zinc, and selenium were not affected. These results support the hypothesis that green tea may provide antioxidant protection in the metabolic syndrome.

Cholestatic effect of epigallocatechin gallate in rats is mediated via decreased expression of Mrp2

Epigallocatechin gallate (EGCG) has been shown to be protective in various experimental models of liver injury, although opposite effects have also been reported. Since its effect on biliary physiology has not been thoroughly investigated, the present study evaluated effect of EGCG on bile flow and bile acid homeostasis in rats. Compared to controls, EGCG treatment decreased bile flow by 23%. Hepatic paracellular permeability and biliary bile acid excretion were not altered by EGCG administration, but biliary glutathione excretion was reduced by 70%. Accordingly, the main glutathione transporter on the hepatocyte canalicular membrane, multidrug resistance-associated protein 2 (Mrp2), was significantly decreased at the protein level. EGCG administration also doubled plasma bile acid levels compared to controls. While protein levels of the main hepatic bile acid transporters were unchanged, the rate-limiting enzyme in the bile acid synthesis, Cyp7a1, was significantly increased by EGCG. Enhanced bile acid synthesis in these animals was also confirmed by a 2-fold increase in plasma marker 7α-hydroxy-4-cholesten-3-one. In contrast, EGCG markedly downregulated major bile acid transporters (Asbt and Ostα) and regulatory molecules (Shp and Fgf15) in the ileum. When EGCG was coadministered with ethinylestradiol, a potent cholestatic agent, it did not show any additional effect on the induced cholestasis. This study shows ability of EGCG to raise plasma bile acid concentrations, mainly through Cyp7a1 upregulation, and to decrease bile production through reduction in Mrp2-mediated bile acid-independent bile flow. In conclusion, our data demonstrate that under certain conditions EGCG may induce cholestasis.

The protective effects of green tea polyphenols: lipid profile, inflammation, and antioxidant capacity in rats fed an atherogenic diet and dextran sodium sulfate

Acute and chronic inflammation and dyslipidemia play a critical role in the development of various diseases, including cardiovascular disease. Green tea polyphenols possess potent antioxidative and anti-inflammatory properties that contribute to the beneficial effects on heart health. The present study was carried out to determine if administration of a green tea extract (Polyphenon(®) E [PPE]; Mitsui Norin Co., Ltd., Tokyo, Japan) at 0.2% in the diet reduces cardiovascular risk factors, including dyslipidemia, inflammation, adiposity, and oxidative stress, in rats fed an atherogenic (high fat, cholesterol, and sugar) diet with dextran sodium sulfate (DSS) in drinking water. DSS treatment increased serum total cholesterol, low-density lipoprotein (LDL)-cholesterol, C-reactive proteins (CRP), and markers of liver toxicity and decreased high-density lipoprotein (HDL)-cholesterol significantly. Adding PPE to the atherogenic diet (PPE-diet) was associated with lower total cholesterol and LDL-cholesterol (P<.001) and increased HDL-cholesterol (P=.001). In addition, the PPE-diet was associated with decreased serum CRP concentration (P=.023) and increased total antioxidant capacity (P=.016) and catalase (P=.001) and glutathione peroxidase (P=.050) activities. The PPE-diet significantly lowered epididymal fat pad weight (P=.009). Feeding the PPE-diet also ameliorated some of the DSS-induced lipid, inflammatory, and oxidative symptoms. In summary, green tea supplementation decreased several cardiovascular risk factors, including body composition, dyslipidemia, inflammatory status, and antioxidant capacity, in rats fed an atherogenic diet. This study supports green tea as an effective dietary component for sustaining cardiovascular health.

Anti-apoptotic effects of tamarind leaves against ethanol-induced rat liver injury†

Objectives

The leaf decoctions of Tamarindus indica (TI) have long been traditionally used in liver ailments. The aim of this study was to investigate the anti-apoptotic activity of TI leaf extract against acute ethanol (EtOH)-induced liver injury. The major constituents of the extract were also examined for standardization purposes.

Methods

Rats (n = 5–7) were orally pretreated with TI leaf extract (25, 50 and 100 mg/kg) for seven days. Silymarin was used as a positive control. Liver tissue biochemical assays included key markers of apoptosis and its redox signalling. Serum enzyme levels were also determined.

Key findings

All graded doses of TI leaf extract mitigated the EtOH-induced liver caspase-3 activation (42, 57 and 64%) as well as DNA fragmentation (32, 47 and 50%), respectively. The highest dose of the extract demonstrated membrane-stabilizing (38%) in addition to glutathione-replenishing (88%) effects. Also, the leaves improved the liver histopathological alterations. Moreover, major plant bioactive polyphenolics, that might be responsible for the extract's observed effects, were isolated and identified.

Conclusions

TI leaf extract demonstrated promising anti-apoptotic hepatoprotective effects in rats. The use of TI leaves in different liver diseases, having apoptosis as the underlying pathology, hence warrants further clinical investigation.

Epigallocatechin-3-O-gallate (EGCG) attenuates FFAs-induced peripheral insulin resistance through AMPK pathway and insulin signaling pathway in vivo

We aimed to investigate the effects and possible mechanisms of Epigallocatechin-3-O-gallate (EGCG) on free fatty acids (FFAs)-induced peripheral insulin resistance in vivo. Overnight-fasted Wistar rats were subjected to 48-h intravenous infusion of either saline or Intralipid plus heparin (IH) with or without different doses of EGCG co-injection. Hyperinsulinemic-euglycemic clamp was performed in awake rats to assess peripheral insulin sensitivity. Co-injection with EGCG significantly prevented FFAs-induced peripheral insulin resistance, decreased plasma markers of oxidative stress: malondialdehyde (MDA) and 8-isoprostaglandin, and increased antioxidant enzymes: superoxide dismutases (SOD) and Glutathione peroxidase (GPx). Furthermore, EGCG treatment reversed IH-induced: (1) decrease in Thr172 phosphorylation of AMP activated protein kinase (AMPK); (2) increase in protein kinase Cθ(PKCθ) membrane translocation and Ser307 phosphorylation of insulin receptor substrate-1 (IRS-1); (3) decrease in Ser473 phosphorylation of Akt and Glucose transporter 4 (GLUT4) translocation in skeletal muscle and adipose tissue. Our data suggest that EGCG treatment ameliorated FFAs-induced peripheral insulin resistance in vivo, and this might be through decreasing oxidative stress and PKCθ membrane translocation, activating the AMPK pathway and improving insulin signaling pathway in vivo. This study suggests the therapeutic value of EGCG in protecting from insulin resistance caused by elevated FFAs.

Sulfur mustard induced oxidative stress and its alteration by epigallocatechin gallate

Sulfur mustard (bis(2-chloroethyl)sulfide; CAS: 505-60-2; abbreviated as HD) is a chemical warfare agent with not well understood mechanism of toxic effect. Deprivation of energy in cells and arising of oxidative stress appears during the exposure. Our experiment is based on investigation of 10mg or 20mg epigallocatechin gallate (EGCG) dose prophylactic effect (1h before HD) in rats exposed to either 20mg or 80 mg of HD. Blood mass, plasma and liver were sampled. Ferric reducing antioxidant power (FRAP), reduced glutathione, thiobarbuturic acid reactive substances (TBARSs), glutathione reductase, glutathione S-transferase and caspase 3 were assessed. Animals were sacrificed one day after exposure. We found significant deprivation of low molecular weight antioxidants due to EGCG but not due to HD. However, HD depleted reduced glutathione. EGCG has no effect to influence TBARS level. EGCG and HD up-regulated glutathione reductase and EGCG down regulated glutathione S-transferase in liver tissue. Regarding caspase, EGCG had anti apoptotic potency. We discuss potency to use EGCG to ameliorate redox balance after HD exposure. The data also appoints at difficulty in antioxidant therapy as prophylaxis to the oxidative stress related toxins exposure and ambivalent modulation of oxidative stress.

Towards a unifying, systems biology understanding of large-scale cellular death and destruction caused by poorly liganded iron: Parkinson's, Huntington's, Alzheimer's, prions, bactericides, chemical toxicology and others as examples

Exposure to a variety of toxins and/or infectious agents leads to disease, degeneration and death, often characterised by circumstances in which cells or tissues do not merely die and cease to function but may be more or less entirely obliterated. It is then legitimate to ask the question as to whether, despite the many kinds of agent involved, there may be at least some unifying mechanisms of such cell death and destruction. I summarise the evidence that in a great many cases, one underlying mechanism, providing major stresses of this type, entails continuing and autocatalytic production (based on positive feedback mechanisms) of hydroxyl radicals via Fenton chemistry involving poorly liganded iron, leading to cell death via apoptosis (probably including via pathways induced by changes in the NF-κB system). While every pathway is in some sense connected to every other one, I highlight the literature evidence suggesting that the degenerative effects of many diseases and toxicological insults converge on iron dysregulation. This highlights specifically the role of iron metabolism, and the detailed speciation of iron, in chemical and other toxicology, and has significant implications for the use of iron chelating substances (probably in partnership with appropriate anti-oxidants) as nutritional or therapeutic agents in inhibiting both the progression of these mainly degenerative diseases and the sequelae of both chronic and acute toxin exposure. The complexity of biochemical networks, especially those involving autocatalytic behaviour and positive feedbacks, means that multiple interventions (e.g. of iron chelators plus antioxidants) are likely to prove most effective. A variety of systems biology approaches, that I summarise, can predict both the mechanisms involved in these cell death pathways and the optimal sites of action for nutritional or pharmacological interventions.

Nigella sativa thymoquinone-rich fraction greatly improves plasma antioxidant capacity and expression of antioxidant genes in hypercholesterolemic rats

The antioxidant activities of the thymoquinone-rich fraction (TQRF) extracted from Nigella sativa and its bioactive compound, thymoquinone (TQ), in rats with induced hypercholesterolemia were investigated. Rats were fed a semipurified diet supplemented with 1% (w/w) cholesterol and were treated with TQRF and TQ at dosages ranging from 0.5 to 1.5 g/kg and 20 to 100 mg/kg body wt, respectively, for 8 weeks. The hydroxyl radical (OH(.))-scavenging activity of plasma samples collected from experimental rats was measured by electron spin resonance. The GenomeLab Genetic Analysis System was used to study the molecular mechanism that mediates the antioxidative properties of TQRF and TQ. Plasma total cholesterol and low-density-lipoprotein cholesterol levels were significantly decreased in the TQRF- and TQ-treated rats compared to untreated rats. Feeding rats a 1% cholesterol diet for 8 weeks resulted in a significant decrease in plasma antioxidant capacity, as measured by the capacity to scavenge hydroxyl radicals. However, rats treated with TQRF and TQ at various doses showed significant inhibitory activity toward the formation of OH(.) compared to untreated rats. Upon examination of liver RNA expression levels, treatment with TQRF and TQ caused the up-regulation of the superoxide dismutase 1 (SOD1), catalase, and glutathione peroxidase 2 (GPX) genes compared to untreated rats (P<0.05). In support of this, liver antioxidant enzyme levels, including SOD1 and GPX, were also apparently increased in the TQRF- and TQ-treated rats compared to untreated rats (P<0.05). In conclusion, TQRF and TQ effectively improved the plasma and liver antioxidant capacity and enhanced the expression of liver antioxidant genes of hypercholesterolemic rats.