Structural characterization and antioxidant activity evaluation of a polysaccharide obtained from the wheat aleurone layer fermented by Agrocybe aegerita

Abstract

Solid-state fermentation (SSF) is considered one of the most effective biotransformation strategies for enhancing the bioactivity of polysaccharides. In this study, the wheat aleurone layer was fermented using Agrocybe aegerita, and the resulting polysaccharides exhibited significantly enhanced antioxidant activity. Among them, the polysaccharide fraction designated as FALP-1, which showed the strongest antioxidant activity, was selected for structural characterization and further evaluation of its antioxidant effects using an H₂O₂-injured HepG2 cell model. FALP-1, with a molecular weight of 6.39 kDa, consisted of fucose, arabinose, galactose, glucose, xylose, and mannose in a molar ratio of 1.00:38.72:6.38:4.04:75.21:5.04. Structural analyses indicated that FALP-1 is a moderately branched arabinoxylan. Antioxidant evaluations demonstrated that FALP-1 enhanced cell viability and alleviated mitochondrial membrane depolarization. Within a concentration range of 25-400 μg/mL, FALP-1 significantly decreased reactive oxygen species (ROS) and malondialdehyde (MDA) levels in a dose-dependent manner, while increasing the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT). Collectively, these findings suggest that FALP-1 is a structurally distinctive polysaccharide with potent antioxidant activity and provide new insights into the high-value utilization of wheat processing by-products.

Keywords: Agrocybe aegerita; Aleurone layer; Antioxidant activity; Polysaccharides; Solid-state fermentation; Structural characterization.