Preparation of Polyphenol-Rich Herbal Beverages from White Willow (Salix alba) Bark with Potential Alzheimer’s Disease Inhibitory Activity In Silico

Abstract

White willow (Salix alba) is a medicinal plant traditionally used to treat pain and inflammation. The aims of this study were to produce polyphenol-rich herbal beverages from willow bark with different ethanol content, temperatures, and solvent pH and to explore neuroprotective potentials of willow polyphenols. The phenolic compounds quantified in the willow infusions were salicin, chlorogenic acid, epicatechin, p-salicylic acid, and p-coumaric acid; the former three compounds exhibited promising inhibitory potentials against acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) in molecular docking studies. Total phenol content and antioxidant activity were maximum when prepared with 50% ethanol-in-water at room temperature. Although aqueous infusions contained fewer total phenols than those extracted with 50% hydroalcoholic solutions, they enhanced the extraction of chlorogenic acid and salicin content, which may possess promising neuroprotective potentials. The addition of citric acids in hot water infusions led to a higher proportion of non-tannins and had a lighter appearance, which may result in less astringent mouthfeel and better consumer acceptance. Overall, the obtained results indicate that willow bark prepared with hot water and/or with addition of citric acids is rich in bioactive compounds with high antioxidant activity and possible neuroprotective activities in silico, which could serve as valuable ingredients for inclusion in functional beverages.