Ameliorated Effects of (-)-Epigallocatechin Gallate Against Toxicity Induced by Vanadium in the Kidneys of Wistar Rats

Attenuation of methotrexate induced hepatotoxicity by epigallocatechin 3-gallate

Methotrexate (MTX) is currently used as first-line therapy for autoimmune diseases like rheumatoid arthritis, psoriasis, and systemic lupus erythematous. However, its use is limited by its hepatotoxic potential. Epigallocatechin-3-gallate (EGCG), an abundant catechin present in tea possesses potent antioxidant activity and effectively ameliorates oxidative stress-related disorders. This study aimed to investigate the hepatoprotective influence of EGCG in a MTX-induced rat model of hepatotoxicity. Sprague Dawley rats pretreated with EGCG (40 mg kg^-1 b.w., p.o.) were administered a single dose of MTX (20 mg kg^-1 b.w., i.p.) and its hepatoprotective efficacy compared with folic acid (1 mg kg^-1 b.w., i.p.). On day 10, blood samples were collected to determine plasma levels of aspartate aminotransferase (AST), alanine transaminase (ALT), alkaline phosphatase (ALP), and lactate dehydrogenase (LDH), while the livers were examined for histopathogical changes along with levels of oxidative stress measured in terms of myeloperoxidase (MPO) activity, protein carbonylation (PCO), lipid peroxidation (LPO), and activities of cellular enzymatic antioxidants - superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx). MTX significantly increased the plasma levels of AST, ALT, ALP, and LDH, which were prevented by pretreatment with EGCG, and was corroborated by histopathology. Additionally, MTX-induced hepatic oxidative stress as measured by increased generation of MPO, enhanced PCO, LPO, and decreased activities of antioxidant enzymes was mitigated by pretreatment with EGCG. The amelioration of MTX-induced hepatotoxicity by EGCG endorsed the inclusion of an anti-oxidant during chronic administration of MTX.

Catechins: Therapeutic Perspectives in COVID-19-Associated Acute Kidney Injury

Data obtained from several intensive care units around the world have provided substantial evidence of the strong association between impairment of the renal function and in-hospital deaths of critically ill COVID-19 patients, especially those with comorbidities and requiring renal replacement therapy (RRT). Acute kidney injury (AKI) is a common renal disorder of various etiologies characterized by a sudden and sustained decrease of renal function. Studies have shown that 5-46% of COVID-19 patients develop AKI during hospital stay, and the mortality of those patients may reach up to 100% depending on various factors, such as organ failures and RRT requirement. Catechins are natural products that have multiple pharmacological activities, including anti-coronavirus and reno-protective activities against kidney injury induced by nephrotoxic agents, obstructive nephropathies and AKI accompanying metabolic and cardiovascular disorders. Therefore, in this review, we discuss the anti-SARS-CoV-2 and reno-protective effects of catechins from a mechanistic perspective. We believe that catechins may serve as promising therapeutics in COVID-19-associated AKI due to their well-recognized anti-SARS-CoV-2, and antioxidant and anti-inflammatory properties that mediate their reno-protective activities.

Vanadium-Flavonoid Complexes: A Promising Class of Molecules for Therapeutic Applications

Several reports have revealed the superior biological activity of metal ion-flavonoid complexes when compared with the parent flavonoid. Among the different metal ions explored, vanadium and its compounds are in the forefront because of their anticancer and antidiabetic properties. However, the toxicity of vanadium-based ions and their inorganic derivatives limits their therapeutic applications. Complexation of vanadium with flavonoids not only reduces its adverse effects but also augments its biological activity. This Review discusses the nature of coordination in vanadium-flavonoid complexes, their structure-activity correlations, with special emphasis on their therapeutic activities. Several investigations suggest that the superior biological activity of vanadium complexes arise because of their ability to regulate metabolic pathways distinct from those acted upon by vanadium alone. These studies serve to decipher the underlying molecular mechanism of vanadium-flavonoid complexes that can be explored further for generating a series of novel compounds with improved pharmacological and therapeutic performance.

Probing the chemoprevention potential of the antidepressant fluoxetine combined with epigallocatechin gallate or kaempferol in rats with induced early stage colon carcinogenesis

The enhanced chemopreventive action against 1,2 Dimethylhydrazine (DMH)-induced preneoplastic lesion in rats could be achieved via simultaneous administration of the antidepressant fluoxetine (FLX) with two natural polyphenolic compounds viz., kaempferol (KMP) and/or epigallocatechin-gallate (EGCG). The obtained results revealed that single FLX pre-treatment possess a significant apoptotic effect by increasing the activity of serum and colon tissue caspase 3. It also attenuated the DMH driven increase in, colon tissue MDA, NO, PCNA and COX-2 expression as well as serum and colon tissue β-catenin, with a decrease in the multiplicity of ACF and number of MPLs. The combination of FLX with either KMP or EGCG improved the antioxidant, anti-inflammatory and antiproliferating activities but with higher apoptotic activity in case of KMP. Eventually, histopathological assessment of colon tissues exposed that while sole pre-treatment can improve DMH-induced hyperplasia with only moderate inflammatory infiltration, tissues from the combined pre-treatment regimens groups exhibited almost a normal colonic architecture with slight submucosal edema. The study proved that single FLX administration prior to DMH exerts a chemopreventive effect and that the investigated combined pre-treatment regimens demonstrated more potent chemopreventive and antiproliferative actions.

The Regulation of Host Intestinal Microbiota by Polyphenols in the Development and Prevention of Chronic Kidney Disease

Polyphenols are essential antioxidants in our regular diet, and have shown potential antibacterial effects. Other important biological effects, such as anticancer or antibacterial activities, have been demonstrated by some polyphenols. In recent years, the benefits of polyphenols to human health have attracted increasing attention from the scientific community. Recent studies have shown that polyphenols such as anthocyanin, catechin, chlorogenic acid, and resveratrol can inhibit pathogenic bacteria such as Escherichia coli and Salmonella to help regulate intestinal microflora. An imbalance of intestinal microflora and the destruction of intestinal barrier function have been found to have a potential relationship with the occurrence of chronic kidney disease (CKD). Specifically, they can aberrantly trigger the immune system to cause inflammation, increase the production of uremic toxins, and further worsen the condition of CKD. Therefore, the maintenance of intestinal microflora and the intestinal tract in a stable and healthy state may be able to "immunize" patients against CKD, and treat pre-existing disease. The use of common antibiotics may lead to drug resistance in pathogens, and thus beneficial polyphenols may be suitable natural substitutes for antibiotics. Herein we review the ability of different polyphenols, such as anthocyanin, catechin, chlorogenic acid, and resveratrol, to regulate intestinal microorganisms, inhibit pathogenic bacteria, and improve inflammation. In addition, we review the ability of different polyphenols to reduce kidney injury, as described in recent studies.

Protective Effects of Dietary Antioxidants against Vanadium-Induced Toxicity: A Review

Vanadium (V) in its inorganic forms is a toxic metal and a potent environmental and occupational pollutant and has been reported to induce toxic effects in animals and people. In vivo and in vitro data show that high levels of reactive oxygen species are often implicated in vanadium deleterious effects. Since many dietary (exogenous) antioxidants are known to upregulate the intrinsic antioxidant system and ameliorate oxidative stress-related disorders, this review evaluates their effectiveness in the treatment of vanadium-induced toxicity. Collected data, mostly from animal studies, suggest that dietary antioxidants including ascorbic acid, vitamin E, polyphenols, phytosterols, and extracts from medicinal plants can bring a beneficial effect in vanadium toxicity. These findings show potential preventive effects of dietary antioxidants on vanadium-induced oxidative stress, DNA damage, neurotoxicity, testicular toxicity, and kidney damage. The relevant mechanistic insights of these events are discussed. In summary, the results of studies on the role of dietary antioxidants in vanadium toxicology appear encouraging enough to merit further investigations.

Potential immunomodulatory and antioxidant effects of walnut Juglans regia vegetable oil against lead-mediated hepatic damage and their interaction with lipase activity in rats

Environmental pollutants, particularly lead, pose a serious threat to human and animal health that causes disturbances of several functions, including hepatotoxicity. Therefore, the search for a new treatment that could safely and effectively block or reverse liver injuries remains a challenge. This study was carried out to investigate the protective efficacy of Juglans regia vegetable oil (JRVO) against the hepatotoxicity induced by lead. To achieve this aim, adults male rats were treated for 10 days with Pb (0.344 g/kg bw) associated or not with JRVO (0.9 g/kg bw). The rats intoxicated by lead exhibited oxidative stress determined by TBARS, protein carbonyls, liver tumor necrosis factor-α (TNF-α), caspase-3, and antioxidant status: SOD, CAT, GPx, and GSH. Administration of lead increased the levels of plasma hepatic markers (AST, ALT, LDH) and bilirubin, the lipid profiles (total cholesterol, triglycerides, VLDL-Ch, LDL-Ch levels, TBARS, NOx, and PCO), the plasmatic lipase activity and the inflammatory markers, while the plasmatic ALP decreased. Coadministration of JRVO restored all the hepatic markers, the lipid profiles and the antioxidants to near-normal values and lowered the plasmatic lipase activity as well as the elevated thiobarbituric acid reactive substances. Hepatic histological studies confirmed the beneficial role of JRVO through the amelioration of all biochemical parameters. Our results suggest that Juglans regia vegetable oil contains promising substances to counteract the lead intoxication and may be efficient in the prevention of hepatotoxicity complications.

Hepatotoxicity of vanadyl sulfate in nondiabetic and streptozotocin-induced diabetic rats

This study examined the effects of vanadyl sulfate (VOSO₄) on the livers of nondiabetic and streptozotocin-induced diabetic rats. Rats were divided into 6 groups. Groups 1, 2, and 3 consisted of nondiabetic rats that were, respectively, control animals or those receiving an intraperitoneal (i.p.) injection of either 5 or 10 mg·kg^-1 (i.p.) VOSO₄ for 30 days. Groups 4, 5, and 6 consisted of diabetic animals that were, respectively, control animals or those treated with 5 or 10 mg·kg^-1 (i.p.) VOSO₄ for 30 days. Results showed that VOSO₄ reduced body mass in nondiabetic rats, whereas it increased body mass in diabetic groups. Plasma transaminases (aspartate aminotransferase, alanine aminotransferase), lactate dehydrogenase, and alkaline phosphatase activities and malondialdehyde levels were increased, while liver catalase and superoxide dismutase activities were profoundly decreased in diabetic animals in comparison with enzyme activities in the nondiabetic group. Rats in the diabetic group also showed notable oxidative damage to the liver. Treatment of diabetic rats with VOSO₄ decreased the hepatotoxic markers, significantly restored the activities of antioxidant enzymes, and attenuated histopathological changes in liver tissue. In nondiabetic rats, VOSO₄ treatment increased most of the hepatotoxic markers, reduced antioxidant enzyme activities, and induced pronounced oxidative damage in liver tissue. These data suggest that treatment with VOSO₄ exerts toxic effects in healthy animals and significantly prevents liver oxidative damage in streptozotocin-induced diabetic rats, but without total safety. Further studies are needed to clarify its mechanism of action.

Antioxidant and nephro-protective effect of Juglans regia vegetable oil against lead-induced nephrotoxicity in rats and its characterization by GC-MS

Lead (Pb) intoxication remains a major health hazard causing various deleterious effects especially on renal and hematologic system. The current study elucidated the potential protective effect of JRVO against nephrotoxicity induced by lead. Male rats were randomly divided into three groups: group one (control) received ad libitum distilled water and 1 mL of saline solution (0.9 %) given by intra-peritoneal (i.p) injection, group two (Pb) was kept on tap distilled water and animals were i.p, injected daily with lead every two days from day five until day ten, namely the sacrifice day, and group three (Pb+J) was administered by intra-peritoneal injection of Pb with the same dose and same way with Group two, while JRVO extract was administered daily by gavage during ten days. The exposure of lead reduced the number of red and white blood cells. Besides, plasma biomarkers (urea, uric acid, creatinine, LDH and ALP) levels were reduced. Lipid and protein per-oxidations increased and objectified by high TBARS and PCOs levels, while glutathione peroxidase, superoxide dismutase and catalase activities showed a significant decline after ten-day treatment. Conversely, the JRVO prevented kidney biomarker changes by improving hepatotoxicity induced by lead as evidenced by restoring the biochemical markers cited above to near normal levels. Kidney histoarchitecture confirmed the biochemical parameters and the beneficial role of JRVO. It can be concluded that the administration of JRVO alleviates Pb-induced toxicity, thus demonstrating its potent antioxidant efficacy.

Vanadate-Induced Renal cAMP and Malondialdehyde Accumulation Suppresses Alpha 1 Sodium Potassium Adenosine Triphosphatase Protein Levels

It has been demonstrated that vanadate causes nephrotoxicity. Vanadate inhibits renal sodium potassium adenosine triphosphatase (Na, K-ATPase) activity and this is more pronounced in injured renal tissues. Cardiac cyclic adenosine monophosphate (cAMP) is enhanced by vanadate, while increased cAMP suppresses Na, K-ATPase action in renal tubular cells. There are no in vivo data collectively demonstrating the effect of vanadate on renal cAMP levels; on the abundance of the alpha 1 isoform (α₁) of the Na, K-ATPase protein or its cellular localization; or on renal tissue injury. In this study, rats received a normal saline solution or vanadate (5 mg/kg BW) by intraperitoneal injection for 10 days. Levels of vanadium, cAMP, and malondialdehyde (MDA), a marker of lipid peroxidation were measured in renal tissues. Protein abundance and the localization of renal α₁-Na, K-ATPase was determined by Western blot and immunohistochemistry, respectively. Renal tissue injury was examined by histological evaluation and renal function was assessed by blood biochemical parameters. Rats treated with vanadate had markedly increased vanadium levels in their plasma, urine, and renal tissues. Vanadate significantly induced renal cAMP and MDA accumulation, whereas the protein level of α₁-Na, K-ATPase was suppressed. Vanadate caused renal damage, azotemia, hypokalemia, and hypophosphatemia. Fractional excretions of all studied electrolytes were increased with vanadate administration. These in vivo findings demonstrate that vanadate might suppress renal α₁-Na, K-ATPase protein functionally by enhancing cAMP and structurally by augmenting lipid peroxidation.