The chemical structure and biological activities of a novel polysaccharide obtained from Fructus Mori and its zinc derivative

A novel polysaccharide (MFP4P) was isolated from mulberry fruits (Morus alba L.) pulp using a combination of DEAE-Sepharose fast-flow and Sephadex G-100 chromatographic columns. Structural characterization revealed that MFP4P was composed of arabinose, rhamnose, galactose, glucose and galacturonic acid with a molecular weight of 198.2 kDa. The linkage types of MFP4P were proved to be (1 -> 6)-linked alpha-D-Glc, (1 -> 2)-linked alpha-LRha, (1 -> 3)-linked alpha-D-Gal, (1 -> 3)-linked beta-L-Rha and (1 -> )-linked alpha-L-Ara. The MFP4P showed good antioxidant activity with an oxygen radical absorbance capacity value of 121.8 +/- 16.5 mu M trolox equivalent/g. In addition, the MFP4P promoted pancreatic cell proliferation, increased insulin secretion, and enhanced glucose consumption. In the non-toxic range, the polysaccharide and zinc complexes (MFP4P-Zn) exhibited higher antioxidant and hypoglycemic activities than MFP4P at the same concentration. In vivo hypoglycemic study, MFP4P and MFP4P-Zn both showed decreased blood glucose level and glucose tolerance compared with the model control group.