Antidiabetic activities of polysaccharides from Anoectochilus roxburghii and Anoectochilus formosanus in STZ-induced diabetic mice

Six polysaccharides were extracted from different parts (whole plants, roots and leaves) of Anoectochilus roxburghii and Anoectochilus formosanus (ARPs, ARPs-1, ARPs-2, AFPs, AFPs-1 and AFPs-2). Their primary characteristics were identified and their antidiabetic activities were evaluated in STZ-induced diabetic mice. Root polysaccharides (ARPs-1 and AFPs-1) and leaf polysaccharides (ARPs-2 and AFPs-2) were distinct from each other in terms of the Mws, monosaccharide compositions and functional groups. Notably, the primary structures of ARPs and AFPs were similar to those of ARPs-1 and AFPs-1, respectively. In animal experiment, after feeding with polysaccharides samples, the body weight, blood glucose, glycogen, insulin, total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), malondiadehyde (MDA) and antioxidant enzyme activities in liver and kidney of mice were tested to investigate the antidiabetic activities. All polysaccharides exhibited varying antidiabetic activities (antihyperglycemic, antioxidant and antihyperlipidemic activities), which were closely related to their primary characteristics. Furthermore, root polysaccharides with higher Mws and glucose content in both A. roxburghii and A formosanus, exhibited better antidiabetic activities than leaf polysaccharides, and ARPs which showed the best antidiabetic activities had the potential to be used as functional food or medicine for diabetes treatment. (C) 2018 Elsevier B.V. All rights reserved.