Antarctic krill phospholipid complexes of alkyl gallates as rheologically tunable systems with proposed dual-release behavior: chain length synergistically governs hydrolysis and transport for sustained gallic acid delivery

Antarctic krill phospholipids were complexed with alkyl gallates of varying chain lengths. • Complexation via hydrogen bonding was confirmed by docking, FTIR, UV, and NMR. • Hydrolysis rates increased with chain length; intact ester transport showed inverse trend. • Phospholipid complexes reduced both hydrolysis and transport, confirming sustained release. • Strong hydrolysis-transport correlation identified hydrolysis as rate-limiting for absorption. To investigate the value-added potential of Antarctic krill phospholipids for sustained polyphenol delivery, we prepared phospholipid complexes of alkyl gallates with varying chain lengths (methyl, ethyl, propyl, butyl) and characterized them via molecular docking, spectroscopy, and rheology. A dual-release mechanism is proposed, involving two sequential stages: the putative dissociation of alkyl gallates from the phospholipid matrix, and subsequent enzymatic hydrolysis of the ester bond by intestinal lipases. Using everted rat intestinal sac model with HPLC-UV, we systematically evaluated hydrolysis and transport kinetics. Results showed that alkyl chain length significantly modulated hydrolysis rates (increasing with chain length) and intact ester transport (decreasing with chain length). The uniformly reduced hydrolysis and transport rates upon complexation are consistent with the presence of a dissociation step that may act as a sustained-release reservoir. The kinetic parameters for both hydrolysis and transport showed strong linear correlations with chain length, enabling quantitative prediction of release behavior. Download: Download high-res image (300KB) Download: Download full-size image