Structural Characterization and Protective Effects of <i>Camellia oleifera</i> Fruit Shell Polysaccharides against DSS-Induced Ulcerative Colitis in Mice
Jianghui Xin, Tie Wang, Yanghui Ou, Xiang Qiu, Mengjie Li, Yali Zhang, Shengjia Lu, Xu Lang, Litao Guan, Hongliang Yao
Abstract
Plant polysaccharides have been reported to possess multiple pharmacological effects that can inhibit the progression of inflammatory diseases. The shell of Camellia oleifera fruits is a byproduct of the C. oleifera industry that is insufficiently utilized. Herein, a novel polysaccharide (CFP-A) was purified from C. oleifera fruit shells, and its structure elucidation and anti-inflammatory activity against dextran sulfate sodium (DSS)-induced ulcerative colitis were investigated. Structural analysis revealed that CFP-A is a neutral heteropolysaccharide with a molecular weight of 5643 Da, primarily comprising arabinose (Ara), galactose (Gal), and glucose (Glc). The main chain of CFP-A was →3,6)-α- d -Galp-(1→3,6)-α- d -Galp-(1→3,6)-α- d -Galp-(1→3)-α- d -Galp-(1→. The branch chains α- d -Galp-(1→6)-α- d -Galp-(1→, α- l -Araf-(1→[5)-α- l -Araf-(1] 7 →3,5)-α- l -Araf-(1→, and α- l -Araf-(1→[4)-α- d -Glcp-(1] 2 → were respectively connected at the C6 position of →3,6)-α- d -Galp-(1→. CFP-A reduced the expression levels of interleukin-6 and interleukin-1β and the production of nitric oxide in lipopolysaccharide-induced Raw264.7 macrophages; it also downregulated inflammatory factor levels in the colon and alleviated splenic hypertrophy, colonic tissue damage, and apoptosis in DSS-induced colitis. Mechanistically, CFP-A attenuated DSS-induced colonic inflammation in mice by activating the Keap1/Nrf2/HO-1 pathway. Collectively, these findings highlight the potential of CPF-A as a complementary therapy for ulcerative colitis.