Antiamyloidogenic Effects of Ellagic Acid on Human Serum Albumin Fibril Formation Induced by Potassium Sorbate and Glucose

Oxidative stress has the main role in protein conformational changes and consequent direct involvement in different kind of diseases. Potassium sorbate as a widespread industrial preservative and glucose are two important oxidants that can be involved in oxidative stress. In this study the effect of ellagic acid as a phenolic antioxidant on amyloid fibril formation of human serum albumin upon incubation of potassium sorbate and glucose was studied using thioflavin T assay, surface tension, atomic force microscopy, Amadori product, and carbonyl content assays. The thioflavin T assay and atomic force microscopy micrographs demonstrated the antiamyloidogenic effect of ellagic acid on the human serum albumin fibril formation. This antioxidant also had the repair effect on surface tension of the modified human serum albumin (amyloid intermediates), which was destructed, caused by potassium sorbate and glucose. This mechanism takes place because of potent carbonyl stress suppression effect of ellagic acid, which was strengthening by potassium sorbate in the presence and absence of glucose. Potassium sorbate is a potent carbonyl stress inducer in the presence and absence of glucose, which lead to the HSA amyloid fibril formation. Carbonyl stress caused by potassium sorbate and glucose has a key role in HSA structural changes and amyloid abnormalities. These structural changes can be repaired by ellagic acid. Ellagic acid is a potent oxidative stress suppressor and healing antioxidant, which inhibits and repair HSAmyloid fibril formation due to carbonyl contents, and Amadori products suppression, which are formed due to potassium sorbate.