**1. Introduction**

Alzheimer's disease (AD) and Parkinson's disease (PD) are the most common neurodegenerative disorders. They are multifactorial, progressive, age-related, and influenced by genetic and environmental factors. Despite being public health problems and widely studied, there are no effective treatments. The therapies in use at the moment are only symptomatic and focused to ameliorate patients' life quality. Moreover, there are no diagnostic methods for the early detection of these diseases that, especially at the onset, share some pathological hallmarks. There are specific proteins associated with the diseases, but it is still unclear when and how they lose their functionality and become toxic. Several pathways of cellular dysfunction have been described to explain the toxicity associated with the disease, but the pathological role of proteins involved still remains controversial. Currently, the most promising therapeutic approaches are focused on personalized treatments and targeted drugs.

Here, we summarize some relevant features of the new proposed therapies for AD and PD. In the last decade, renewed interest rises toward alternative pharmacological treatments and products of natural origin, especially those associated

with the Mediterranean diet, such as polyphenols. The unexpected benefits and the wide-range properties of polyphenols suggest deepening the study of these molecules for a more comprehensive understanding of their mechanism of action in order to use them in effective therapies.
