Biopolymer-based sequestrants for lowering cholesterol: Structures, in vitro bile acid anion binding effects, and interaction mechanisms

Biopolymers are often used in foods and pharmaceuticals as sequestrants of bile acid anions (BAAs) to reduce cholesterol. However, the in vitro BAA binding effects of biopolymer-based sequestrants (BPBSs) and the corresponding structure–activity relationships have not yet been fully clarified. This review first describes the structural characteristics of BPBSs, including polysaccharide-based and protein-derived biopolymers, as well as their BAA binding ability. Next, the underlying molecular interactions and mechanisms that drive these sequestrants to bind BAAs are discussed, including electrostatic interactions, hydrophobic interactions, hydrogen bonding, physical retention, and their combinations. Furthermore, some useful insights into biopolymer-based BAA sequestrants are provided, such as grafting multiple positively charged groups, introducing hydrogen-bond donors, and incorporating hydrophobic segments into the molecular structures of biopolymers. The aim of this review is to provide useful insights with relevance to design cholesterol-lowering food formulations and maintaining a healthy diet.