Identification of catalase in human livers as a factor that enhances phenytoin dihydroxy metabolite formation by human liver microsomes

Toxicity assessment of perovskite nanocomposites: In vivo study

Perovskite solar cells display potential as a renewable energy source because of their high-power conversion efficiency. However, there is limited understanding regarding the potential impact of perovskite on human health and the ecosystem. In this study, two sets of male Wistar albino rats received 35 injections of perovskite composite at a dosage of 0.372 mg/kg body weight. The animals underwent thorough examinations, encompassing morphometric, hematological, biochemical, histological, and behavioral analyses. Liver, kidney, and testis biopsies were processed and examined histologically. Additionally, two groups of mice (perovskite-treated and control mice, each with n = 10) underwent three behavioral tests: the Elevated Zero Maze test, Marble Burying test, and Light-Dark Box test. Perovskite-treated rats displayed a significant increase in levels of aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, triglycerides, cholesterol, creatinine, blood urea nitrogen, white blood cells, and platelets. However, total bilirubin levels decreased, with no significant alteration in albumin values. Furthermore, exposure to perovskite composite resulted in a slight decrease in lactate dehydrogenase and red blood cell count. Histopathological examination revealed hepatic hydropic degeneration, Kupffer cells hypertrophy and hyperplasia, and renal hydropic degeneration, while testicular tissues remained unaffected. Moreover, behavioral changes were observed in perovskite-treated mice, including depression, anxiety, and compulsive burying activity. These findings suggest that exposure to perovskite can lead to significant hematological and biochemical changes, as well as hepatorenal histopathological alterations and behavioral changes. Additionally, chronic exposure to perovskite materials may induce structural and functional alterations in vital organs.

Biological Effect of Quercetin in Repairing Brain Damage and Cerebral Changes in Rats: Molecular Docking and In Vivo Studies

This study examined the protective effect of quercetin against high-altitude-induced brain damage in rats. A molecular docking study was performed to investigate the potential effect of quercetin in reducing brain damages through its ability to target the oxidative stress enzymes. Biomarker assessment screening assays were also performed then followed by in vivo studies. Three groups of rats were divided into the control group, an untreated animal model group with induced brain damage, and finally, the quercetin treated group that received quercetin dose equal to 20 mg/kg of their body weights. Molecular docking studies and biomarker assessment screening assays proved the potential effect of quercetin to affect the level of representative biomarkers glutathione (GSH), glutathione reductase (GR), glutathione-S-transferase (GST), glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA). Additionally, the protective effect of quercetin against high altitude, low pressure, and low oxygen was also investigated by exploring the brain histopathology of experimental rats. Brain damage was observed in the untreated animal model group. After treatment with quercetin, the cerebral edema in the brain tissues was improved significantly, confirming the protective effects of quercetin. Therefore, quercetin can be used as a natural food additive to protect from the highaltitude-induced brain damage.

Spirulina platensis Alleviated the Hemotoxicity, Oxidative Damage and Histopathological Alterations of Hydroxychloroquine in Catfish (Clarias gariepinus)

The current study aims at evaluating the toxicity of hydroxychloroquine (HCQ) as a pharmaceutical residue in catfish (Clarias gariepinus) and the protective role of Spirulina platensis (SP). Four groups were used in this study: (1) a control group, (2) a group exposed to 3.16 mg/l of HCQ, (3) a group exposed to 3.16 mg/l of HCQ + 10 mg/l of SP, and (4) a group exposed to 3.16 mg/l of HCQ + 20 mg/l of SP for 15 days of exposure. The HCQ-treated group showed a significant decline in the hematological indices and glucose, total protein, and antioxidant levels in relation to the control group, whereas the HCQ-treated group showed a significant increase in the levels of creatinine, uric acid, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) as well as the percentage of poikilocytosis and nuclear abnormalities of RBCs in relation to the control group. The histopathological evaluation of the liver indicated dilation of the central vein, vacuolization, degeneration of hepatocytes and pyknotic nuclei, as well as reduction of glomeruli, dilation of Bowman's space, and degeneration of renal tubules in the kidney of the HCQ-treated group. Spirulina platensis (SP) rendered the hematological and biochemical indexes as well as antioxidant levels and the histological architecture to normal status in a dose-dependent manner. Accordingly, the current study recommends the use of SP to remedy the toxic effects of HCQ.

Study on cerebroprotective actions of Clerodendron glandulosumleaves extract against long term bilateral common carotid artery occlusion in rats

Stroke is a major cause of death and disability worldwide. The resulting burden on the society continues to grow, with increase in the incidence of stroke. Oxidative stress has been involved in the pathogenesis of several neurological diseases including acute stroke.Focal and global cerebral ischemia represents diseases that are common in the human population.In recent years much attention is being paid towards the exploration of herbal preparation, antioxidant agents and combination therapies including COX-2 inhibitors in experimental model of stroke.Possible effect of a hydroalcoholic leaf extract of Clerodendron glandulosumColeb (C. glandulosum)on oxidant-antioxidant status in ischemia-hypoperfusion injury in the rat forebrain has been investigated.Healthy adult male Wistar albino rats were divided into five groups (n=8). Group I was served as Sham control (normal saline 1ml/kg, orally), group II was served hypoperfusion control (normal saline 1ml/kg, orally), group III, group IV were served as hydroalcoholic extract treated (200 and 400mg/kg, orally) and group V was treated with Quercetin (10mg/kg, orally) for 14days to assess preventive and curative effects of C. glandulosum. Flavonoid and phenolic compounds exhibit a broad spectrum of biological activity, including antioxidant. C. glandulosum extract (200 and 400mg/kg, p.o) was administered orally, once daily for a period of 2 weeks after the occlusion of BCCA. After 14th days rats were subjected to behavioral studies. After behavioral studies animals were sacrificed and brain was removed and homogenized. Estimation of Lipid peroxidation (LPO) Myeloperoxidase (MPO), estimation of protein levels and the activities of Superoxide dismutase (SOD), Catalase (CAT), were performed. Infarct size and histopathological changes were observed in treated groups.

In vitro metabolism of isoliquiritigenin by human liver microsomes

Isoliquiritigenin (2',4',4-trihydroxychalcone), a chalcone found in licorice root and other plants, has shown potent antitumor, antioxidant, and phytoestrogenic activity in vitro. In preparation for in vivo studies, the metabolism of isoliquiritigenin by human liver microsomes was investigated, and seven phase 1 metabolites were identified. In addition to aromatic hydroxylation that occurred on the A or B ring to form 2',4,4',5'-tetrahydroxychalcone or butein, respectively, reduction of the carbon-carbon double bond of an alpha,beta-unsaturated ketone and cyclization occurred to form 2',4,4'-trihydroxydihydrochalcone and (Z/E)-6,4'-dihydroxyaurone. All metabolites were characterized and identified by using liquid chromatography-tandem mass spectrometry with comparison to authenticated compounds. Finally, monoclonal antibody inhibitors of specific human cytochrome P450 (P450) enzymes and recombinant human P450 enzymes were used to identify the enzymes responsible for the formation of the major mono-oxygenated metabolites, and P450 2C19 was found to be a significant enzyme in the formation of butein from isoliquiritigenin, which also has anticancer activity. Cytochromes P450, reactive oxygen species, and peroxidases can all contribute to the formation of (Z/E)-6,4'-dihydroxyaurone in human liver microsomes.

Endogenous Uremic Substances are not Involved in the Reduced Hepatic Extraction of Metoprolol in Bilateral Ureter-Ligated Rats†

The hepatic extraction of metoprolol is reduced in rats with bilateral ureter ligation (BUL)-induced renal failure. The aim of the present study was to evaluate the effect of uremic substances on the hepatic metabolism of metoprolol in rats with BUL. The metabolic rate in the liver microsomes of BUL rats was similar to that in sham rats, and there was no significant difference between sham and BUL rats in the effect of the supernatant of liver homogenates on the metabolism. The rate of metabolism in the liver microsomes in the presence of the plasma of BUL rats was also similar to that in the presence of the plasma of sham rats. These findings indicated that uremic substances which accumulate in BUL rats do not directly inhibit the activity of CYP2D2, which is responsible for the metabolism of metoprolol in the rat liver.

Drug bioactivation, covalent binding to target proteins and toxicity relevance

A number of therapeutic drugs with different structures and mechanisms of action have been reported to undergo metabolic activation by Phase I or Phase II drug-metabolizing enzymes. The bioactivation gives rise to reactive metabolites/intermediates, which readily confer covalent binding to various target proteins by nucleophilic substitution and/or Schiff's base mechanism. These drugs include analgesics (e.g., acetaminophen), antibacterial agents (e.g., sulfonamides and macrolide antibiotics), anticancer drugs (e.g., irinotecan), antiepileptic drugs (e.g., carbamazepine), anti-HIV agents (e.g., ritonavir), antipsychotics (e.g., clozapine), cardiovascular drugs (e.g., procainamide and hydralazine), immunosupressants (e.g., cyclosporine A), inhalational anesthetics (e.g., halothane), nonsteroidal anti-inflammatory drugs (NSAIDSs) (e.g., diclofenac), and steroids and their receptor modulators (e.g., estrogens and tamoxifen). Some herbal and dietary constituents are also bioactivated to reactive metabolites capable of binding covalently and inactivating cytochrome P450s (CYPs). A number of important target proteins of drugs have been identified by mass spectrometric techniques and proteomic approaches. The covalent binding and formation of drug-protein adducts are generally considered to be related to drug toxicity, and selective protein covalent binding by drug metabolites may lead to selective organ toxicity. However, the mechanisms involved in the protein adduct-induced toxicity are largely undefined, although it has been suggested that drug-protein adducts may cause toxicity either through impairing physiological functions of the modified proteins or through immune-mediated mechanisms. In addition, mechanism-based inhibition of CYPs may result in toxic drug-drug interactions. The clinical consequences of drug bioactivation and covalent binding to proteins are unpredictable, depending on many factors that are associated with the administered drugs and patients. Further studies using proteomic and genomic approaches with high throughput capacity are needed to identify the protein targets of reactive drug metabolites, and to elucidate the structure-activity relationships of drug's covalent binding to proteins and their clinical outcomes.