Novel Zn(II) complexes of native and modified Dendrobium hancockii polysaccharides: Synthesis, characterization, and
Kui-Wu Wang1, Zhe-Han Zhao1, Hai-Jiang Zhang2
1School of Food Science and Biotechnology, Zhejiang Gongshang University, Hangzhou, 310018, China.
Abstract:
Native, carboxymethylated, and degraded Dendrobium hancockii polysaccharides containing Zn(II) complexes, namely PDH-Zn, CPDH-Zn, and DGPDH-Zn, were synthesized for the first time. The three Zn(II) containing complexes and their original polysaccharides were characterized by chemical composition analysis, pre-column derivatization HPLC, FT-IR, XPS, XRD, TGA/DTG, SEM, and their biological activities were assayed in vitro. The results showed that the complexes changed the chemical composition, sugar chain conformation and surface morphology of original polysaccharides. The complexes showed different antioxidant activity, significantly increased α-glucosidase inhibitory and antibacterial activity than original polysaccharides. Kinetic analysis indicated that PDH-Zn and DGPDH-Zn were noncompetitive-anticompetitive mixed inhibitors with Ki/Kis of 3.16/1.58 and 3.18/1.67 mg/mL, respectively. CPDH-Zn was a competitive- noncompetitive mixed inhibitor with Ki/Kis of 4.54/14.14 mg/mL. These results suggested that PDH-Zn, CPDH-Zn, and DGPDH-Zn can contribute to the development of functional foods.
