Protein misfolding and aggregation into fibrillar deposits is a common feature of a large group of degenerative diseases affecting the central nervous system or peripheral organs, termed protein misfolding disorders (PMDs). Despite their established toxic nature, clinical trials aiming to reduce misfolded aggregates have been unsuccessful in treating or curing PMDs. An interesting possibility for disease intervention is the regular intake of natural food or herbal extracts, which contain active molecules that inhibit aggregation or induce the disassembly of misfolded aggregates. Among natural compounds, phenolic molecules are of particular interest, since most have dual activity as amyloid aggregation inhibitors and antioxidants. In this article, we review many phenolic natural compounds which have been reported in diverse model systems to have the potential to delay or prevent the development of various PMDs, including Alzheimer's and Parkinson's diseases, prion diseases, amyotrophic lateral sclerosis, systemic amyloidosis, and type 2 diabetes. The lower toxicity of natural compounds compared to synthetic chemical molecules suggest that they could serve as a good starting point to discover protein misfolding inhibitors that might be useful for the treatment of various incurable diseases.

In the present work, phytochemical contents (total phenolic content, total flavonoids, and condensed tannins), antioxidant potentials, and antimicrobial activities of three plants in the Mediterranean genus Erodium (Erodium glaucophyllum, Erodium hirtum, and Erodium guttatum) from the Tunisia region were analyzed. The results showed that E. glaucophyllum contained high levels of polyphenols, flavonoids, and tannins. Therefore, E. glaucophyllum possesses high antioxidant activities (2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power scavenging activities), and high inhibition of linoleic acid oxidation. All three plants exhibited high antimicrobial activities. This study highlights tree plants’ importance as dietary sources for natural antioxidants can be used in traditional medicine and the pharmaceutical industry.