From Langmuir films to molecular docking: unraveling the interfacial code of (−)-epigallocatechin gallate binding with milk fat globule membrane components

NMR and Langmuir show EGCG binds MFGM phospholipids/proteins, altering key regions. • EGCG reduces sphingomyelin collapse pressure, proving strong binding. • H-bonding and hydrophobic forces drive EGCG-MFGM complexes. • PC binds strongest among lipids, while β-casein shows optimal protein binding. This study investigated the interaction mechanisms between epigallocatechin gallate (EGCG) and key milk fat globule membrane (MFGM) components, aiming to elucidate the basis for MFGM-catechin interactions. Initial evidence from 1 H and 31 P NMR spectroscopy revealed EGCG-induced chemical shifts in critical regions. Furthermore, Langmuir monolayer studies simulating MFGM demonstrated concentration-dependent interactions of EGCG with the membrane interface. A significant reduction in the collapse pressure of sphingomyelin monolayers (from 43.84 ± 2.58 mN/m to 27.41 ± 3.06 mN/m) provided direct evidence of strong EGCG-phospholipid binding. Atomic force microscopy (AFM) further corroborated these interactions, indicating EGCG-induced lipid aggregation and protein structural alterations. Fourier transform infrared (FTIR) spectroscopy, molecular docking, and molecular dynamics simulations identified hydrogen bonding and hydrophobic interactions as the primary driving forces for these phenomena. Overall, these results elucidate the molecular mechanisms underpinning EGCG-MFGM component interactions, providing a foundational understanding for leveraging MFGM constituents to alleviate EGCG-related astringency in food applications. Download: Download high-res image (242KB) Download: Download full-size image