Inhibitory Activities of Antioxidant Flavonoids from Tamarix gallica on Amyloid Aggregation Related to Alzheimer’s and Type 2 Diabetes Diseases

The prevention of amyloid aggregation is promising for the treatment of age-related diseases such as Alzheimer’s (AD) and type 2 diabetes (T2D). Ten antioxidant flavonoids isolated from the medicinal halophyte Tamarix gallica were tested for their amyloid aggregation inhibition potential. Glucuronosylated flavonoids show relatively strong inhibitory activity of Amyloid β (Aβ) and human islet amyloid polypeptide (hIAPP) aggregation compared to their aglycone analogs. Structure–activity relationship of the flavonoids suggests that the catechol moiety is important for amyloid aggregation inhibition, while the methylation of the carboxyl group in the glucuronide moiety and of the hydroxyl group in the aglycone flavonoids decreased it.