Beneficial Effects of Flavonoids Against Parkinson's Disease

Parkinson's disease (PD) is characterized by the progressive degeneration of dopaminergic (DA) neurons in the substantia nigra pars compacta and decreases in striatal dopamine levels. These changes led to several clinical symptoms: rigidity, resting tremor, and bradykinesia. Although the cause of PD remains unclear, it is widely accepted that oxidative stress, neuroinflammation, mitochondrial dysfunction, and insufficient support of neurotrophic factors are involved in the pathophysiology of the disease. However, novel regimens to prevent neurodegeneration and restore the degenerated nigrostriatal DA system are still required. In recent years, there has been a growing interest in naturally occurring phytochemicals, which are believed to reduce the risk of neurodegenerative diseases. This review provides an overview of the scientific literature concerning the preventive and protective roles of flavonoids, one of the largest families of phytochemicals, against PD. In addition to providing antioxidant and anti-inflammatory effects, flavonoids exhibit a neuroprotective effect by activating antiapoptotic pathways that target mitochondrial dysfunction and induce neurotrophic factors. This review suggests that flavonoids may be promising natural products for the prevention of PD and could potentially be utilized as therapeutic compounds against PD, even though there was no report showing that the treatment with flavonoids could restore the aberrant phenotypes of patients with PD.