| The mushroom Inonotus obliquus(Inonotus obliquus(Fr.) Pilat), commonly known as Kabanoanatake in Japan and Chaga in Russia, is a white parasitic fungus that grows on the mature birch, and is mainly distributed in Russia, Poland and other countries located at latitudes of 45?N–50?N. Since the 16 th century, it had been widely used as a folk remedy for the treatment of gastrointestinal disease, cardiovascular disease and diabetes. I. obliquus has been reported to contain various constituents such as polysaccharides, polyphenols, triterpenoids. Polysaccharides is one of the main components of I. obliquus and it has been shown to exhibit many biological activities including anti-tumor, antioxidant, anti-diabetic, immune-stimulating effects.Firstly, the ball milling technology was used in the pretreatment of I. obliquus. The yield of triterpenoids was not significantly improved(P>0.05), however, the yields of polysaccharides and polyphenols were increased 2-5 fold in ball milled powders as compared with those of untreated one. The antioxidant properties of the extracts were also significantly improved(P<0.05). Ball milled powders showed higher values in the bulk density, angles of repose and slide, water solubility index and swelling capacity(P<0.05), but lower values in the water holding capacity and oil holding capacity. Scanning electron microscopy(SEM) revealed that the surface morphologies of the powders were changed after ball mill-treatment.Secondly, in order to study the anti-diabetic activity of I. obliquus polysaccharides(IOPS), the IOPS was administered orally at different doses(300, 600 and 900 mg/kg) to streptozotocin(STZ) induced diabetic mice. The results showed that IOPS treatment significantly reduced the levels of blood glucose, TC, TG, LDL-C, and led to increased levels of hepatic glycogen, HDL-C and the activity of antioxidant enzymes in liver and kidney. The results of histopathology also showed that IOPS could protect tissues against peroxidation damage.Finally, a new I. obliquus polysaccharide-iron(?) complex(IOPS-iron) was prepared and characterized. The highest iron content of IOPS-iron(?) complex(19.40%) was obtained at the optimized conditions: the ratio of IOPS and FeCl3 was 3:5(w/w), the pH was 10, the reaction temperature was 30°C and the reaction time was 6 h. The qualitative identification of IOPS-iron(?) complex verified that the iron(?) ions were coordinated to the IOPS instead of physical mixture. The surface morphology, intrinsic viscosity and particle size of IOPS were changed with the iron loading. The result of FTIR indicated the iron(?) ions were coordinated by the hydroxyl of the IOPS, and the FTIR spectrum of IOPS-iron(?) complex was similar to that of FeOOH. The EPR response of IOPS-iron(?) were characterized by the signals at g?2.0 and g?4.3, which might occupy the tetrahedral and octahedral site with rhombic distortion. The CD spectrum suggested the molecular conformation of IOPS was changed with the iron loading. IOPS-iron(?) complex was found to have good digestive availability(97%), high DPPH radical scavenging activity(IC50=114.8 ?g/mL) and inhibitory activity of the liver lipid peroxidation(IC50=156.3 ?g/m L).In summary, the ball milling technology could be used in the pretreatment of I. obliquus, and to improve the yields of active ingredients of I. obliquus. The IOPS has the potential values in the treatment of diabetes and its complications. The IOPS could be coordinated with iron(?), and the IOPS-iron(?) might be used as a new iron supplementary. |
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