Geraniol attenuates oxidative stress and neuroinflammation-mediated cognitive impairment in D galactose-induced mouse aging model.

D-galactose (D-gal) administration was proven to induce cognitive impairment and aging in rodents' models. Geraniol (GNL) belongs to the acyclic isoprenoid monoterpenes. GNL reduces inflammation by changing important signaling pathways and cytokines, and thus it is plausible to be used as a medicine for treating disorders linked to inflammation. Herein, we examined the therapeutic effects of GNL on D-gal-induced oxidative stress and neuroinflammation-mediated memory loss in mice. The study was conducted using six groups of mice (6 mice per group). The first group received normal saline, then D-gal (150 mg/wt) dissolved in normal saline solution (0.9%, w/v) was given orally for 9 weeks to the second group. In the III group, from the second week until the 10th week, mice were treated orally (without anesthesia) with D-gal (150 mg/kg body wt) and GNL weekly twice (40 mg/kg body wt) four hours later. Mice in Group IV were treated with GNL from the second week up until the end of the experiment. For comparison of young versus elderly mice, 4 month old (Group V) and 16-month-old (Group VI) control mice were used. We evaluated the changes in antioxidant levels, PI3K/Akt levels, and Nrf2 levels. We also examined how D-gal and GNL treated pathological aging changes. Administration of GNL induced a significant increase in spatial learning and memory with spontaneously altered behavior. Enhancing anti-oxidant and anti-inflammatory effects and activating PI3K/Akt were the mechanisms that mediated this effect. Further, GNL treatment upregulated Nrf2 and HO-1 to reduce oxidative stress and apoptosis. This was confirmed using 99mTc-HMPAO brain flow gamma bioassays. Thus, our data suggested GNL as a promising agent for treating neuroinflammation-induced cognitive impairment.

The Inhibitory Effect of Geraniol on CCL4-induced Hepatorenal Toxicity in Pregnant Mice through the PI3K/AKT Signaling Pathway.

Background: Hepatotoxicity caused by CCL4 is well known. Geraniol (GNL) has high antioxidant effect that can induces liver regeneration. However, the protective effect of GNL effect on CCL4-induced hepatorenal toxicity in pregnant mice has not yet been studied. Objective: To investigate whether GNL could protect against oxidative stress induced by CCL4 via the nuclear factor erythroid 2-related factor 2 (Nrf2) pathway, which is regulated by phosphatidylinositol 3 kinase/protein kinase B (PI3K/AKT), and has been found to have protective effects on renal and hepatic tissues. Materials and Methods: Forty-eight female albino mice weighing 25-30 g were randomly allocated to 4 groups: Group I served as a control; Group II received a toxicity-inducing single dose of 15 µL of CCL4 on the 4th day after mating; Group III received 40 mg/kg GNL + CCL4 (with GNL from the 1st day of assimilation to delivery); and Group IV received GNL alone from the 1st day of assimilation to the end of the delivery period. GNL was evaluated for its protective effects on hepatotoxicity in CCL4-treated pregnant mice. Litter size, weight, survival rate, and resorption were recorded. In addition, H & E staining was done for liver and kidney pathology as well as biochemical markers and oxidative markers malondialdehyde, superoxide dismutase, and catalase were analyzed. Results: CCL4 significantly reduced survival rate and increased resorption after exposure. Alanine transaminase and aspartate aminotransferase concentrations in the serum, tissue MDA, blood urea nitrogen, and creatinine were increased after CCL4 exposure. GNL improved enzyme and antioxidant levels and prevented CCL4-induced hepatic injury in mice. Caspase-3 cleavage was decreased by GNL, which increased PI3K, phosphorylated AKT, Nrf2, and B-cell lymphoma 2. Conclusion: GNL demonstrates a protective effect against CCl4-induced hepatorenal toxicity, mediated through the activation of the PI3K/AKT signaling pathway and the upregulation of Nrf2. These findings highlight the potential therapeutic implications of GNL in mitigating oxidative stress and inflammation in liver and kidney tissues.

Potential inhibitory effect of geraniol isolated from lemongrass (Cymbopogon commutatus Stapf) on tilmicosin-induced oxidative stress in cardiac tissue.

An experimental study has been conducted to investigate the efficacy of geraniol (GNL) isolated from lemomgrass in protecting against cardiac toxicity induced by tilmicosin (TIL) in albino mice. Compared to TIL-treated mice, those supplemented with GNL had a thicker left ventricular wall and a smaller ventricular cavity. Studies of TIL animals treated with GNL showed that their cardiomyocytes had markedly changed in diameter and volume, along with a reduction in numerical density. After TIL induction, animals showed a significant increase in the protein expression of TGF-ß1, TNF-α, nuclear factor kappa B (NF-kB), by 81.81, 73.75 and 66.67%, respectively, and hypertrophy marker proteins ANP, BNP, and calcineurin with respective percentages of 40, 33.34 and 42.34%. Interestingly, GNL significantly decreased the TGF-ß1, TNF-α, NF-kB, ANP, BNP, and calcineurin levels by 60.94, 65.13, 52.37, 49.73, 44.18 and 36.84%, respectively. As observed from histopathology and Masson's trichrome staining, supplementation with GNL could rescue TIL-induced cardiac hypertrophy. According to these results, GNL may protect the heart by reducing hypertrophy in mice and modulating biomarkers of fibrosis and apoptosis.

Isoimperatorin therapeutic effect against aluminum induced neurotoxicity in albino mice.

Background: Although aluminum (Al) is not biologically crucial to the human body, classical studies have demonstrated that excessive human exposure to Al can induce oxidative damage, neuroinflammatory conditions and neurotoxic manifestations implicated in Alzheimer's disease (AD). Exposure to Al was reported to be associated with oxidative damage, neuroinflammation, and to enhance progressive multiregional neurodegeneration in animal models. Several plant-derived natural biomolecules have been recently used to reduce the toxic effects of Al through decreasing the oxidative stress and the associated diseases. A good candidate still to be tested is an active natural furanocoumarin, the isoimperatorin (IMP) that can be extracted from Lemon and lime oils and other plants. Here, we examined the neuroprotective effects of IMP on aluminum chloride (AlCl3)-induced neurotoxicity in albino mice. Methods: Twenty-four male albino mice were used in this study. Mice were randomly devided into 5 groups. The first group was given distilled water as a control, the second group was given AlCl3 orally (10 mg/wt/day) starting from the 2nd week to the end of the 6th week, the third group received AlCl3 orally and IMP interperitoneally, i. p. (30 mg/wt/day) starting from week 2 till week 6 where IMP was supplement 1st and then 4 h later AlCl3 was given to mice. The fourth group received the control (IMP 30 mg/wt, i. p.) from the 2nd week till the end of the experiment. Rodent models of central nervous system (CNS) disorders were assessed using object location memory and Y-maze tests in 6th week began. Essential anti-inflammatory and oxidative stress indicators were evaluated, including interleukin-1 ß (IL-1ß), tumor necrosis factor α (TNF-α), malondialdehyde (MDA), total antioxidant capacity (TAC), and catalase activity (CAT). In addition, serum levels of brain neurotransmitters such as corticosterone, acetylcholine (ACh), dopamine and serotonin in brain homogenates were measured calorimetrically. Results: The study results revealed that the daily treatment of AlCl3 upregulated the TNF-α and IL-1ß levels, increased MDA accumulation, and decreased TAC and CAT activity. In addition, aluminum induced a reduction in concentrations of ACh, serotonin and dopamine in the brain. However, IMP significantly ameliorates the effect of AlCl3 through modulating the antioxidant and regulating the inflammatory response through targeting Nrf2 (NF-E2-related factor 2) and mitogen-activated protein kinase (MAPK). Conclusion: Thus, IMP might be a promising treatment option for neurotoxicity and neurodegenerative diseases, such as Alzheimer's disease and Parkinson's disease, which are associated with neuro-inflammation and oxidative stress.

Hypoxia inducible factor-1α (HIF-1α) as an early predictor of acute hydrogen cyanamide (Dormex) poisoning.

Hydrogen cyanamide (Dormex) is a plant growth regulator that is classified as a highly toxic poison. There are no definite investigations to help in its diagnosis and follow-up. This study aimed to investigate the role of hypoxia-inducible factor-1α (HIF-1α) in the diagnosis, prediction, and follow-up of Dormex-intoxicated patients. Sixty subjects were equally divided into two groups: group A, the control group, and group B, the Dormex group. Clinical and laboratory evaluations, including arterial blood gases (ABG), prothrombin concentration (PC), the international normalized ratio (INR), a complete blood count (CBC), and HIF-1α, were done on admission. CBC and HIF-1α were repeated for group B 24 and 48 h after admission to track abnormalities. Group B also had brain computed tomography (CT). Patients with abnormal CT scans were referred for brain magnetic resonance imaging (MRI). Significant differences in levels of HB, WBCs, and platelets were also detected in group B up to 48 h after admission, as white blood cells (WBCs) rose with time and hemoglobin (HB) and platelets diminished. The results described a highly significant difference in HIF-1α between the groups, and it depended on the clinical condition; therefore, it can be used in the prediction and follow-up of patients up to 24 h after admission.

Sweroside: An iridoid glycoside of potential neuroprotective, antidiabetic, and antioxidant activities supported by molecular docking.

Oxidative stress can be a series burden on human health and may lead to many chronic diseases such as diabetes and neurological disorders. The use of natural products to scavenge the reactive oxygen species has attracted the attention of many researchers, to safely manage these conditions with fewer side effects, in available and cost-effective ways. The current study aimed at the isolation and structure elucidation of sweroside from Schenkia spicata (Gentianaceae) and the evaluation of its antioxidant, antidiabetic, neuroprotective, and enzyme inhibitory potential via in vitro and in silico studies. The antioxidant potential was evaluated by a variety of assays as ABTS, CUPRAC and FRAP, showing values of 0.34 ± 0.08, 21.14 ± 0.43, and 12.32 ± 0.20 mg TE/g, respectively, while demonstrating 0.75 ± 0.03 mmol TE/g for phosphomolybdenum (PBD) assay. Acetylcholinestrase (AChE), butyrylcholinesterase (BChE) and tyrosinase inhibitory activities were used to evaluate the neuroprotective effect, while the antidiabetic potential was evaluated by measuring α-amylase and glucosidase inhibitory activities. Results revealed that sweroside showed antioxidant and inhibitory effects on the enzymes tested with the exception of AChE. It demonstrated good tyrosinase inhibitory ability with 55.06 ± 1.85 mg Kojic acid equivalent /g. Regarding the antidiabetic ability, the compound displayed both amylase and glucosidase (0.10 ± 0.01 and 1.54 ± 0.01 mmol Acarbose equivalent/g, respectively) inhibitory activities. Molecular docking studies of sweroside on the active sites of the aforementioned enzymes in addition to NADPH oxidase were performed using Discovery Studio 4.1 software. Results revealed good binding affinities of sweroside to these enzymes mainly through hydrogen bonds and van der Waals interactions. Sweroside can be an important antioxidant and enzyme inhibitory supplement, yet further in vivo and clinical studies are required.

Glycoprotein G-protein Coupled Receptors in Disease: Luteinizing Hormone Receptors and Follicle Stimulating Hormone Receptors.

Signal transduction by luteinizing hormone receptors (LHRs) and follicle-stimulating hormone receptors (FSHRs) is essential for the successful reproduction of human beings. Both receptors and the thyroid-stimulating hormone receptor are members of a subset of G-protein coupled receptors (GPCRs) described as the glycoprotein hormone receptors. Their ligands, follicle-stimulating hormone (FSH) and luteinizing hormone (LH) and a structurally related hormone produced in pregnancy, human chorionic gonadotropin (hCG), are large protein hormones that are extensively glycosylated. Although the primary physiologic functions of these receptors are in ovarian function and maintenance of pregnancy in human females and spermatogenesis in males, there are reports of LHRs or FSHRs involvement in disease processes both in the reproductive system and elsewhere. In this review, we evaluate the aggregation state of the structure of actively signaling LHRs or FSHRs, their functions in reproduction as well as summarizing disease processes related to receptor mutations affecting receptor function or expression in reproductive and non-reproductive tissues. We will also present novel strategies for either increasing or reducing the activity of LHRs signaling. Such approaches to modify signaling by glycoprotein receptors may prove advantageous in treating diseases relating to LHRs or FSHRs function in addition to furthering the identification of new strategies for modulating GPCR signaling.

Polyoxometalates function as indirect activators of a G protein-coupled receptor.

The luteinizing hormone receptor (LHR), a G protein-coupled receptor (GPCRs), can initiate signaling in the presence of some vanadium-containing compounds as a result of vanadium compound interactions with the membrane lipids and/or the cell membrane lipid interface. The ability of LHR expressed in CHO cells to initiate signaling in the presence of highly charged and water-soluble polyoxovanadates (POV) including Na3[H3V10O28] (V10) and two mixed-valence heteropolyoxovanadates, K(NH4)4[H6V14O38(PO4)]·11H2O (V14) and [(CH3)4N]6[V15O36(Cl)] (V15), was investigated here. Interactions of the vanadium compounds with CHO cells decreased the packing of membrane lipids, drove aggregation of LHR and increased signal transduction by LHR. Cell responses were comparable to, or in the case of V14 and V15, greater than those seen for cells treated with human chorionic gonadotropin (hCG), a naturally-occurring LHR ligand produced in early pregnancy in humans. POV effects were observed for CHO cells where LHR was expressed at 10 000 or 32 000 LHR per cell but not when LHR was overexpressed with receptor numbers >100 000 LHR per cell. To determine which POV species were present in the cell medium during cell studies, the speciation of vanadate (V1), V10, V14 or V15 in cell medium was monitored using 51V NMR and EPR spectroscopies. We found that all the POVs initiated signaling, but V15 and V10 had the greatest effects on cell function, while V1 was significantly less active. However, because of the complex nature of vanadium compounds speciation, the effects on cell function may be due to vanadium species formed in the cell medium over time.

Effects of vanadium(IV) compounds on plasma membrane lipids lead to G protein-coupled receptor signal transduction.

Luteinizing hormone receptors (LHR), expressed at physiological numbers <30,000 receptors per cell, translocate to and signal within membrane rafts following binding of human chorionic gonadotropin (hCG). Similarly LHR signal in cells when treated with bis(maltolato)oxovanadium(IV) (BMOV), bis(ethylmaltolato)oxovanadium(IV) (BEOV) or VOSO4, which decrease membrane lipid packing. Overexpressed LHR (>85,000 receptors per cell) are found in larger clusters in polarized homo-transfer fluorescence resonance energy transfer (homo-FRET) studies that were not affected by either hCG or vanadium compounds. Intracellular cyclic adenylate monophosphate (cAMP) levels indicate that only clustered LHR are active and produce the intracellular second messenger, cAMP. When LHR are over-expressed, cell signaling is unaffected by binding of hCG or vanadium compounds. To confirm the existence of intact complex, the EPR spectra of vanadium compounds in cell media were obtained using 1 mM BMOV, BEOV or VOSO4. These data were used to determine intact complex in a 10 µM solution and verified by speciation calculations. Effects of BMOV and BEOV samples were about two-fold greater than those of aqueous vanadium(IV) making it likely that intact vanadium complex are responsible for effects of LHR function. This represents a new mechanism for activation of a G protein-coupled receptor; perturbations in the lipid bilayer by vanadium compounds lead to aggregation and accumulation of physiological numbers of LHR in membrane raft domains where they initiate signal transduction and production of cAMP, a second messenger involved in signaling.