Metal chelation, radical scavenging and inhibition of A beta sub(42) fibrillation by food constituents in relation to Alzheimer's disease

Various food constituents have been proposed as disease-modifying agents for Alzheimer's disease (AD), due to epidemiological evidence of their beneficial effects, and for their ability to ameliorate factors linked to AD pathogenesis, namely by: chelating iron, copper and zinc; scavenging reactive oxygen species; and suppressing the fibrillation of amyloid-beta peptide (A beta ). In this study, nine different food constituents (l-ascorbic acid, caffeic acid, caffeine, curcumin, (-)-epigallocatechin gallate (EGCG), gallic acid, propyl gallate, resveratrol, and alpha -tocopherol) were investigated for their effects on the above factors, using metal chelation assays, antioxidant assays, and assays of A beta sub(42) fibrillation. An assay method was developed using 5-Br-PAPS to examine the complexation of Zn(II) and Cu(II). EGCG, gallic acid, and curcumin were identified as a multifunctional compounds, however their poor brain uptake might limit their therapeutic effects. The antioxidants l-ascorbic acid and alpha -tocopherol, with better brain uptake, deserve further investigation for specifically addressing oxidative stress within the AD brain. Chemical compounds * l-Ascorbic acid (PubChem CID: 54670067) * Caffeic acid (PubChem CID: 689043) * Caffeine (PubChem CID: 2519) * Curcumin (PubChem CID: 969516) * (-)-Epigallocatechin gallate (PubChem CID: 65064) * Gallamide (PubChem CID: 69256) * Gallic acid (PubChem CID: 370) * Propyl gallate (PubChem CID: 4947) * Resveratrol (PubChem CID: 445154) * alpha -Tocopherol (PubChem CID: 14985)