Structure Characterization and Hypoglycaemic Activities of Two Polysaccharides from Inonotus obliquus.

Ping Liu,Jiao Xue,Peipei Wu,Shisheng Tong,Wenxia Dong

doi:10.3390/molecules23081948

Abstract

In the present study, two polysaccharides (HIOP1-S and HIOP2-S) were isolated and purified from Inonotus obliquus using DEAE-52 cellulose and Sephadex G-100 column chromatography. The structural characterization and in vitro and in vivo hypoglycaemic activities of these molecules were investigated. HPLC analysis HIOP1-S was a heterpolysaccharide with glucose and galactose as the main compontent monosaccharides (50.247%, molar percentages). However, HIOP2-S was a heterpolysaccharide with glucose as the main monosaccharide (49.881%, molar percentages). The average molecular weights of HIOP1-S and HIOP2-S were 13.6 KDa and 15.2 KDa, respectively. The β-type glycosidic bond in HIOP1-S and HIOP2-S was determined using infrared analysis. 1H-NMR spectra indicated that HIOP2-S contains the β-configuration glycosidic bond, and the glycoside bonds of HIOP1-S are both α-type and β-type. The ultraviolet scanning showed that both HIOP1-S and HIOP2-S contained a certain amount of binding protein. Congo red test showed that HIOP1-S and HIOP2-S could form a regular ordered triple helix structure in the neutral and weakly alkaline range. HIOP1-S and HIOP2-S showed strong α-glucosidase inhibitory activities and increased the glucose consumption of HepG2 cells. In addition, Streptozotocin (STZ)-induced hyperglycaemic mice were used to evaluate the antihyperglycaemic effects of HIOP1-S and HIOP2-S in vivo. The results showed that HIOP2-S had antihyperglycaemic effects. Taken together, these results suggest that HIOP1-S and HIOP2-S have potential anti-diabetic effects.

Highlights

HIOP1-S and HIOP2-S showed strong α-glucosidase inhibitory activities and increased the glucose consumption of HepG2 cells
Diabetes mellitus (DM) is a chronic metabolic disorder caused by insulin deficiency or functional disturbance of the receptors
HIOP2-S primarily comprised glucose, galactose and mannose, but not fucose, with the highest glucose content of up to 49.881%. These results demonstrated that the monosaccharide ratios of the two polysaccharides were different, and the monosaccharide compositions of HIOP1-S and HIOP2-S were different from previous findings [14]

Summary

Introduction

Diabetes mellitus (DM) is a chronic metabolic disorder caused by insulin deficiency or functional disturbance of the receptors. Diabetes mellitus has become a worldwide epidemic, with the number of diabetes mellitus patients increasing annually. In 2013, 382 million individuals worldwide suffered from diabetes, and the total number of individuals with diabetes is expected to reach 592 million by 2035 [1]. The effective anti-diabetic medicines in the pharmaceutical market include α-glucosidase inhibitors, biguanides and sulphonylureas. These frequently used synthetic anti-diabetic drugs are associated with adverse effects and even toxicity after long-term use [2,3]. The potential adverse effects of these anti-diabetic drugs include weight gain, stomach upset, lactic acidosis, swelling of legs or ankles, etc. There is an urgent need to develop new medications with lower side effects for diabetes

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Conclusion