Neuroprotective Effects of Fisetin in Alzheimer's and Parkinson's Diseases: From Chemistry to Medicine.

According to the epidemiological reports published by the World Health Organization, the proportion of elderly people (over 60 years) will increase from 11% to 22% by 2050 worldwide. This increase will be associated with a growing rate of morbidity and mortality of age-related diseases. Mental and neurodegenerative diseases are important health problems in elderly people. Therefore, recent research has been focused on finding effective neuroprotective agents with low adverse effects. Over the last two decades, much attention has been drawn to plant-derived bioactive compounds as novel therapeutic agents for treatment of neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD). Among them, flavonoid chemical class is known as one of the most bioactive and non-toxic phytochemicals, which are widely found in different herbal medicines and edible plants. Fisetin is one of the most common and bioactive flavonoids which possesses potential neuroprotective effects. Fisetin also enhances learning and memory, decreases neuronal cell death, and suppresses oxidative stress. The present paper aims to critically evaluate the available literature regarding the beneficial effects of fisetin on neurodegenerative diseases, especially AD and PD. In addition, we provide information regarding the chemistry, sources, bioavailability and clinical impacts of fisetin to provide a broad spectrum for the use of this compound as a new approach to the treatment of AD and PD.