Therapeutic effects of Cyperus rotundus rhizome extract on memory impairment, neurogenesis and mitochondria in beta-amyloid rat model of Alzheimer's disease

Walnut-Derived Peptide Enhances Mitophagy via JNK-Mediated PINK1 Activation to Reduce Oxidative Stress in HT-22 Cells

Mitophagy has a neuroprotective effect on reactive oxygen species (ROS)-induced neurodegenerative diseases. The walnut-derived polypeptide (TW-7) has antioxidant activity and protects nerves by promoting autophagy. However, its action mechanism against oxidative stress through mitophagy remains obscure. Therefore, we aimed to assess the effects of TW-7 on HT-22 cells under oxidative stress. Mitochondrial ultrastructure and cristae number were observed by transmission electron microscopy. The results showed that TW-7 (100 μM) restored the fluorescence intensity of the mitochondrial membrane potential to 0.99 ± 0.04 (P < 0.05), decreased H₂O₂-induced opening of mitochondrial permeability transition pores, and inhibited mitochondrial bioenergetic deficits. Moreover, it significantly increased activities of antioxidant enzymes to 186.88 ± 5.40 U/mgprot, 40.08 ± 0.87 mU/mgprot, and 23.57 ± 0.77 U/mgprot (P < 0.05), based on superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) assay results, respectively. Consistently, it decreased cellular and mitochondrial ROS levels by 51.71 ± 0.81 and 49.75 ± 0.69% (P < 0.05). TW-7 also downregulated C-Jun N-terminal kinase (JNK) phosphorylation and activated PTEN-induced putative kinase 1 (PINK1)-mediated mitophagy in H₂O₂-induced HT-22 cells treated with JNK activator (anisomycin) and inhibitor (SP600125). Furthermore, TW-7 inhibited the mitochondrial apoptosis pathway by downregulation of the cytoplasmic cytochrome C, caspase-9, and cleaved-caspase-3 expression. Additionally, BDNF and SNAP-25 levels significantly increased to protect the synaptic function. Collectively, TW-7 improved oxidative stress-mediated nerve cell injury via JNK-regulated PINK1-mediated mitophagy.

Toxic Substance-induced Hippocampal Neurodegeneration in Rodents as Model of Alzheimer’s Dementia

BACKGROUND: Alzheimer’s Dementia (AD) cases are increasing with the global elderly population. To study the part of the brain affected by AD, animal models for hippocampal degeneration are still necessary to better understand AD pathogenesis and develop treatment and prevention measures. AIM: This study was a systematic review of toxic substance-induced animal models of AD using the Morris Water Maze method in determining hippocampal-related memory impairment. Our aim was reviewing the methods of AD induction using toxic substances in laboratory rodents and evaluating the report of the AD biomarkers reported in the models. METHODS: Data were obtained from articles in the PubMed database, then compiled, categorized, and analyzed. Eighty studies published in the past 5 years were included for analysis. RESULTS AND DISCUSSION: The most widely used method was intracerebroventricular injection of amyloid-β _substances. However, some less technically challenging techniques using oral or intraperitoneal administration of other toxic substances also produce successful models. Instead of hippocampal neurodegeneration, many studies detected biomarkers of the AD pathological process while some reported inflammation, oxidative stress, neurotrophic factors, and changes of cholinergic activity. Female animals were underrepresented despite a high incidence of AD in women. CONCLUSION: Toxic substances may be used to develop AD animal models characterized with appropriate AD pathological markers. Characterization of methods with the most easy-handling techniques and more studies in female animal models should be encouraged.

Cyperus spp.: A Review on Phytochemical Composition, Biological Activity, and Health-Promoting Effects

Cyperaceae are a plant family of grass-like monocots, comprising 5600 species with a cosmopolitan distribution in temperate and tropical regions. Phytochemically, Cyperus is one of the most promising health supplementing genera of the Cyperaceae family, housing ≈950 species, with Cyperus rotundus L. being the most reported species in pharmacological studies. The traditional uses of Cyperus spp. have been reported against various diseases, viz., gastrointestinal and respiratory affections, blood disorders, menstrual irregularities, and inflammatory diseases. Cyperus spp. are known to contain a plethora of bioactive compounds such as α-cyperone, α-corymbolol, α-pinene, caryophyllene oxide, cyperotundone, germacrene D, mustakone, and zierone, which impart pharmacological properties to its extract. Therefore, Cyperus sp. extracts were preclinically studied and reported to possess antioxidant, anti-inflammatory, antimicrobial, anticancer, neuroprotective, antidepressive, antiarthritic, antiobesity, vasodilator, spasmolytic, bronchodilator, and estrogenic biofunctionalities. Nonetheless, conclusive evidence is still sparse regarding its clinical applications on human diseases. Further studies focused on toxicity data and risk assessment are needed to elucidate its safe and effective application. Moreover, detailed structure-activity studies also need time to explore the candidature of Cyperus-derived phytochemicals as upcoming drugs in pharmaceuticals.