Structural characterization, acute toxicity assessment and protective effects of selenylated apple pectin on dextran sulfate sodium-induced ulcerative colitis.

This study was aimed at investigating the structural characterization, acute toxicity and protective effect of selenylated apple pectin on dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice. Selenylated apple pectin was characterized by ion chromatography, NMR and SEC-RI-MALLS. The acute toxicity and protective effect of selenylated apple pectin against UC were investigated by gavage administration in mice. The organ state and coefficients, inflammatory cytokine (IL-6, IL-10 and TNF-α) contents in serum, GSH-Px activity and MPO content in colon tissues were also evaluated. The results indicated that selenylated apple pectin was non-toxic and contained 244.28 µgselenium per g. The monosaccharide composition with different molar ratios, different relative molecular weights and a weakened signal peak (CH2-O group) at 3-4 ppm were observed after selenylation. The selenylated apple pectin showed the protective effect against UC by down-regulating IL-6 and TNF-α contents and up-regulating the IL-10 content in serum, as well as increasing the GSH-Px activity and decreasing the MPO content in colon tissues. Moreover, DSS-induced alterations were effectively recovered by a high-dose sample. These findings provide evidence in support of selenylated apple pectin as a novel dietary selenium supplement for UC protection.

Formation of protein-anthocyanin complex induced by grape skin extracts interacting with wheat gliadins: Multi-spectroscopy and molecular docking analysis.

In order to broaden the application of grape skin anthocyanin extract (GSAE) in flour products, the interaction of gliadin (Gli) and GSAE were investigated. Seven anthocyanin components from GSAE were identified by HPLC-MS2, which could form complexes with Gli having different binding rates based on UV, FTIR and HPLC analysis. The fluorescence quenching experiment showed that GSAE was capable of efficiently quenching the intrinsic fluorescence of Gli through hydrophobic interactions, and the binding parameters were near to one unit at the given temperatures. Additionally, GSAE binding changed the conformational properties of Gli, increasing α-helix and ß-turn content, but decreasing ß-sheet and irregular coil content. The molecular docking suggested that Gli possessed various binding sites bound with different anthocyanin monomers, mainly depending on hydrogen bonds and hydrophobic interactions. These findings further proved the formation of Gli-GSAE complex, indicating the potential of anthocyanins as natural colorant.