Evaluation, Purification And Structural Characterization Of The Hypoglycemic Components In Catathelasma Ventricosum Extract

Diabetes mellitus is a life-threatening chronic metabolic disease caused by lack of insulinand/or insulin dys function, characterized by high levels of glucose in the blood(hyperglycemia). Millions worldwide suffer from diabetes and its complications. Significantly,it has been recognized that type2diabetes is an important preventable disease and can beavoided or delayed by lifestyle intervention. Presently, there are many chemical andbiochemical hypoglycemic agents (synthetic drugs), that are used intreating diabetes and areeffective in controlling hyperglycemia. However, as they may have harmful side-effects andfail to significantly alter the course of diabetic complications, natural anti-diabetic drugs frommedicinal plants have attracted a great deal of attention. Medicinal mushrooms have beenvalued as a traditional source of natural bioactive compounds over many centuries and havebeen targeted as potential hypoglycemic and anti-diabetic agents.Evaluation of the chemical composition and antihyperglycemic and antioxidant activityof five wild edible mushrooms (Clitocybe maxima, Catathelasma ventricosum, Strophariarugoso-annulata, Craterellus cornucopioides and Laccaria amethystea) from SouthwestChina.The chemical composition assay includes proximate analysis (moisture,ash, crudeprotein, crude fat, total carbohydrates and total energy), bioactive compounds analysis, fattyacid analysis, amino acid analysis, phenolic compounds analysis and mineral analysis of thesemushrooms. Furthermore, assays of α-glucosidase inhibitory and α-amylase inhibitoryactivity were used for evaluating antihyperglycemic activity of the mushrooms, and assays ofreducing power, chelating effect on ferrous ions, scavenging effect on hydroxyl freeradicalsand1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity were used forevaluating antioxidant activity of the mushrooms. Based on the results, ethanolic and aqueousextract of these mushroom all showed antihyperglycemic and antioxidant potential. Inparticular, the aqueous extract of C. ventricosum revealed the highest α-glucosidase inhibitoryactivity (EC50value2.74μg/mL), DPPH radical scavenging activity (EC50value2.86mg/mL)and reducing power (EC0.5value0.96mg/mL), while the aqueous extractof L. amethysteashowed the highest α-amylase inhibitory activity (EC50value4.37μg/mL) and metal chelatingactivity (EC50value2.13mg/mL).Response surface methodology (RSM) was adapted to optimizethe conditions ofpolysaccharides extract. The optimized condition shall be extract temperature85oC, extracttime3hours and the ratio of material to solvent0.05. Under the optimized condition,polysaccharides yield7.59g, α-glycosidase inhibition activity2.85μg/mL, α-amylaseinhibitory activity2.57μg/mL, AGEs90%, DPPH scavenging capacity2.31μg/mL, reducingpower0.87μg/mL, metal chelating capacity4.96μg/mL. The result shows that RSM is theoptimization methods with good prospects.It is the first time to extract polysaccharides (CVPs) from Catathelasma ventricosum.The antihyperglycemic and antioxidant activity of CVPs instreptozotocin-induced diabeticmice were examined. Compared with untreated diabetic mice, the administration of CVPs for30days caused a significant decrease in the concentrations of blood glucose, total cholesterol (TC), triglycerides (TG), low-density lipoprotein-cholesterol (LDL-C) and maleic dialdehyde(MDA), and a significant increase in the concentrations of high densitylipoprotein-cholesterol (HDL-C) and the activities of antioxidant enzymes. Specially, whennormal mice were treated with CVPs, all detection indexes and pathologic morphologies ofliver, kidney and pancreas are similar to untreated normal mice, which indicated CVPs aresafe for normal mice.CVP-1S was purified with solid phase extractions using DEAE-52and Sephadex G-100columns. The average size of SPC-2was1.5×104Da, and it was mainly composed of glucose(94.2%) with the conformation of β-pyran ring. The structural features of CVP-1S-2S wereinvestigated by partial hydrolysis with acid, methylation analysis, NMR, etc. The resultsrevealed that the main backbone chain of CVP-1S was (1,6)-D-glucopyranose residuesinterspersed with other small amount residues. The branched structure of SPC-2was provedintuitively by atomic force microscopy and scanning electron microscope.The biomass and the ability of selenium accumulation of Catathelasma ventricosum withtwo methods were firstly investigated. The result showed that it will obtain91.3g dry fruitingbody per gram of substrate,69.8μg Se per gram of dry fruiting body and the ratio of seleniumaccumulation and organic selenium were92.6%under the solid culture condition; the resultshowed that it will obtain4.3g dry mycelia per litre of culture medium,254.3μg Se per gramof dry mycelia and the ratio of selenium accumulation and organic selenium were84.6%under the liquid culture condition.SPC-2S was purified with solid phase extractions using DEAE-52and Sephadex G-100columns. The average size of SPC-2was1.6×105Da, and it was mainly composed of glucose(87.4%) with the conformation of β-pyran ring. The branched structure and surfacemorphology of SPC-2was proved intuitively byAFM and SEM.The antidiabetic potential of SPC-2was tested in STZ-induced diabetic mice. Afteradministration ofSPC-2for30days, SPC-2treatment significantly reduced the levels ofmalondialdehyde (MDA) and low-density lipoprotein cholesterol (LDL-C) that wereincreased by the STZ treatment. Further, the SPC-2treatment led to increased activity ofantioxidant enzymes in liver and kidney and high-density lipoprotein cholesterol (HDL-C)that were decreased by the STZ. The results of histopathology also showed SPC-2projectedtissues against peroxidation damage and maintained tissue integrity. Our results demonstratedthat SPC-2appears to have antihyperlipidemic and antioxidant properties in a diabeticcondition.