stigmasterol and Memory-Disorders

Exposures to toxic levels of vanadium and soluble vanadium compounds cause behavioral impairments and neurodegeneration via free radical production. Consequently, natural antioxidant sources have been explored for effective and cheap remedy following toxicity. Grewia carpinifolia has been shown to improve behavioral impairments in vanadium-induced neurotoxicity, however, the active compounds implicated remains unknown. Therefore, this study was conducted to investigate ameliorative effects of bioactive compounds from G. carpinifolia on memory and behavioral impairments in vanadium-induced neurotoxicity.. Sixty BALB/c mice were equally divided into five groups (A-E). A (control); administered distilled water, B (standard); administered α-tocopherol (500 mg/kg) every 72 hr orally with daily dose of sodium metavanadate (3 mg/kg) intraperitoneally, test groups C, and D; received single oral dose of 100 μg β-spinasterol or stigmasterol (bioactive compounds from G. carpinifolia), respectively, along with sodium metavanadate and the model group E, received sodium metavanadate only for seven consecutive days. Memory, locomotion and muscular strength were accessed using Morris water maze, Open field and hanging wire tests. In vivo antioxidant and neuroprotective activities were evaluated by measuring catalase, superoxide dismutase, MDA, H. In Morris water maze, stigmasterol significantly (p ≤ 0.05) decreased escape latency and increased swimming time in target quadrant (28.01 ± 0.02; 98.24 ± 17.38 s), respectively, better than α-tocopherol (52.43 ± 13.25; 80.32 ± 15.21) and β-spinasterol (42.09 ± 14.27; 70.91 ± 19.24) in sodium metavanadate-induced memory loss (112.31 ± 9.35; 42.35 ± 11.05). β-Spinasterol and stigmasterol significantly increased exploration and latency in open field and hanging wire tests respectively. Stigmasterol also increased activities of antioxidant enzymes, decreased oxidative stress markers and lipid peroxidation in mice hippocampal homogenates, and increased MBP expression.. The findings of this study indicate a potential for stigmasterol, a bioactive compound from G. carpinifolia in improving cognitive decline, motor coordination, and ameliorating oxidative stress in vanadium-induced neurotoxicity.

Topics: Animals; Antioxidants; Behavior, Animal; Cognitive Dysfunction; Down-Regulation; Hippocampus; Lipid Peroxidation; Male; Memory Disorders; Mice; Mice, Inbred BALB C; Myelin Basic Protein; Neurotoxicity Syndromes; Oxidative Stress; Stigmasterol; Vanadates

Stigmasterol, a kind of phytosterol, is present in small amounts in various foods. In the present study, we investigated the effects of stigmasterol on scopolamine-induced memory impairments using the passive avoidance and the Morris water maze tasks in mice. In addition, changes in memory-related molecules, including extracellular signal-regulated kinase (ERK) and cAMP response element-binding protein (CREB), were examined following the administration of stigmasterol. Scopolamine-induced memory impairments were significantly attenuated by the administration of stigmasterol (10mg/kg) in the passive avoidance task. In the Morris water maze task, the escape latencies were significantly decreased in the stigmasterol-treated group compared to the scopolamine-treated group during the training phase. The swimming times within the target zone during the probe trial were significantly increased as compared to scopolamine-treated mice. Furthermore, the ameliorating effect of stigmasterol on scopolamine-induced memory dysfunction was blocked by a sub-effective dose of dizocilpine (MK-801), an NMDA receptor antagonist, and tamoxifen, an estrogen receptor antagonist, in the passive avoidance task. In addition, the expression levels of phosphorylated ERK and CREB in the hippocampus were significantly increased by stigmasterol, which was blocked by tamoxifen or MK-801 with scopolamine. These results suggest that stigmasterol-induced cognitive ameliorative effects are mediated by the enhancement of cholinergic neurotransmission system via the activation of estrogen or NMDA receptors.

Topics: Animals; Avoidance Learning; Cognition; Cyclic AMP Response Element-Binding Protein; Dizocilpine Maleate; Extracellular Signal-Regulated MAP Kinases; Gene Expression Regulation; Hippocampus; Male; Maze Learning; Memory Disorders; Mice; Mice, Inbred ICR; Phosphorylation; Scopolamine; Stigmasterol; Tamoxifen