Abstract

Rice bran is an abundant by-product of rice processing, however, studies on the structural characteristics and biological activities of its glucans remain limited. A novel glucan (RBP0) was isolated and purified from rice bran, with an average molecular weight of 4.57 × 10 3  g/mol. Structural analyses revealed that RBP0 is mainly composed of glucose, and its backbone consists of →4)-α-D-Glc p -(1→, →4,6)-α-D-Glc p -(1→, and →3,4)-α-D-Glc p -(1 → linkages. In vitro assays demonstrated that RBP0 possessed antioxidant activity, with scavenging rates of 83.25%, 63.84%, and 45.42% against DPPH·, ABTS+·, and ·OH radicals, respectively, at 8 mg/mL, although these effects were weaker than those of vitamin C. Moreover, RBP0 regulated the expression of genes associated with allergy-related immune cells in an intestinal model, suggesting its potential anti-allergic properties. This study provides a solid scientific foundation for the structural elucidation of rice bran polysaccharides and supports their further development and practical application as functional ingredients.