Obesity and diabetes are the most common metabolic disorders, which are strongly related to Alzheimer's disease (AD) in aging. Diabetes and obesity can lead to the accumulation of amyloid plaques, neurofibrillary tangles (NFTs), and other symptoms of AD through several pathways, including insulin resistance, hyperglycemia, hyperinsulinemia, chronic inflammation, oxidative stress, adipokines dysregulation, and vascular impairment. Currently, the use of polyphenols has been expanded in animal models and in-vitro studies because of their comparatively negligible adverse effects. Among them, quercetin (QT) is one of the most abundant polyphenolic flavonoids, which is present in fruits and vegetables and displays many biological, health-promoting effects in a wide range of diseases. The low bioavailability and poor solubility of QT have also led researchers to make various QT-involved nanoparticles (NPs) to overcome these limitations. In this paper, we review significant molecular mechanisms induced by diabetes and obesity that increase AD pathogenesis. Then, we summarize in vitro, in vivo, and clinical evidence regarding the anti-Alzheimer, anti-diabetic and anti-obesity effects of QT. Finally, QT in pure and combination form using NPs has been suggested as a promising therapeutic agent for future studies.

肥胖和糖尿病是最常见的代谢性疾病，与衰老中的阿尔茨海默氏病（AD）密切相关。糖尿病和肥胖可通过多种途径导致淀粉样斑块，神经原纤维缠结（NFT）以及AD的其他症状的积累，包括胰岛素抵抗，高血糖症，高胰岛素血症，慢性炎症，氧化应激，脂肪因子失调和血管损伤。目前，由于多酚的不良影响相对可以忽略不计，因此在动物模型和体外研究中的使用已得到扩展。其中，槲皮素（QT）是最丰富的多酚类黄酮之一，它存在于水果和蔬菜中，并在多种疾病中显示出许多促进健康的生物作用。QT的低生物利用度和较差的溶解度还导致研究人员制造各种涉及QT的纳米颗粒（NP）来克服这些限制。在本文中，我们综述了糖尿病和肥胖引起的增加AD发病机理的重要分子机制。然后，我们总结了有关QT的抗阿尔茨海默病，抗糖尿病和抗肥胖作用的体外，体内和临床证据。最后，已提出使用NP的纯净和组合形式的QT被认为是未来研究的有希望的治疗剂。QT的抗糖尿病和抗肥胖作用。最后，已提出使用NP的纯净和组合形式的QT被认为是未来研究的有希望的治疗剂。QT的抗糖尿病和抗肥胖作用。最后，已提出使用NP的纯净和组合形式的QT被认为是未来研究的有希望的治疗剂。