The potential role of dietary polyphenols in Parkinson’s disease

Cumulative evidence now suggests that the abnormal aggregation of the neuronal protein alpha-synuclein is critically involved in the pathogenesis of synucleinopathies, of which Parkinson’s disease (PD) is the most prevalent. Development of neuropathology appears to be linked to events that accelerate the rate of aggregation of alphasynuclein from monomers, via soluble oligomeric intermediates, into amyloid fibrils. Although increasing data suggest that oligomeric aggregates, not amyloid fibrils, disrupt or permeabilise cellular membranes, the nature of the neurotoxic species and its precise molecular mechanism still remain largely unknown, hampering the development of an effective treatment for the disease. Currently, there is no approved therapeutic agent directed toward preventing alpha-synuclein aggregation and only symptomatic therapies are available with a limited timeframe of utility. Numerous studies have demonstrated the protective effects of dietary polyphenols against neuronal damage in PD. The aim of this review is to look at what research has been done so far to show that dietary polyphenolic compounds can effectively interfere with alpha-synuclein oligomerisation. Evidence in the role and mechanisms of diet-derived phenolic products may guide the design of novel therapeutic drugs that can block early stages of amyloid self-assembly in PD and related synucleinopathies.