Differences in in vitro bioavailability, bioaccessibility, and antioxidant capacity depending on linkage type of luteolin 4'-O-glucosides.

Abstract

This study investigated the effect of glycosylation on the antioxidant capacities of luteolin by analyzing the differences in in vitro bioaccessibility, bioavailability, and bioactivity based on glucose anomers. Luteolin, luteolin 4'-O-alpha-glucoside (L4αG), and luteolin 4'-O-beta-glucoside (L4βG) were used to obtain clear and direct research results, excluding the influence of complex food matrices. L4αG exhibited lower water solubility, digestive stability, and aglycone-releasing ability compared to L4βG. However, L4αG most effectively alleviated intracellular oxidative stress in H₂O₂-induced Caco-2 cells by inhibiting the mitogen-activated protein kinases and activating nuclear factor erythroid-2-related factor signaling pathways. The findings suggested that the alpha-anomer of glucose in L4αG significantly (p < 0.05) enhanced intracellular antioxidant capacity by activating the cellular antioxidant enzyme systems rather than acting as an exogenous scavenger compared to L4βG. This study highlights a new approach for exploring natural antioxidants based on flavonoid aglycones with high cell affinity and electron-donating capacity.