Compare Study Of Polysaccharides And Their Derivatives From Several Atlantic Canadian Seaweeds Against Type-2Diabetes Mellitus

Diabetes mellitus is a group of diseases characterized by chronic hyperglycemia due to deficiency of insulin action which is a common basis and leads to characteristic abnormalities in the metabolism of carbohydrate, lipid, and protein. As a world wisely spread diseases, diabetes mellitus is mainly divided into type-1diabetes (Insulin dependent, IDDM) and type-2diabetes (Non-insulin dependent, NIDDM). Type-2diabetes is the most common form and has escalated to epidemic proportions. Main factors of type-2diabetes are related with a genetic disposition, overweight or obesity, lack of physical activity, consumption of high-fat, low-fiber diets, oxidative stress, and possibly deficiencies in certain minerals. Insulin resistance is an initial mechanism to reduce type-2diabetes. Adipose tissue stores excess energy in the form of triglyceride, and releases free fatty acids in response to energy requirements. It is one of the insulin sensitive peripheral organizations and plays a critical role in insulin resistance and type-2diabetes. Oral agents including insulin sensitizers, secretagogue, bile acid sequestrant, alpha-glucosidase inhibitor, and DPP-IV inhibitor are applied for improving glucose production, carbohydrate intake, insulin secretion, and peripheral uptake associated with type-2diabetes. However, the disadvantages of these agents provide more challenges for anti-diabetes research. Seaweeds species have been used traditionally as food, vegetable, as well as herbal drugs, and many investigations revealed that seaweeds have not only nutritional effects but also beneficial properties to cure various diseases and maintain good health. It has been reported that polysaccharides from marine sources may possess anti-diabetic potential. The objective of this project is to develop natural polysaccharides and their derivatives from marine algae for anti-diabetes studies.Polysiphonia lanosa, Furcellaria lumbricalis, Palmar ia palmata, Ascophyllum nodosum, Fucus vesiculosus and Ulva lactuca, were collected from Atlantic Canadian coast where is one of the richest sources of seaweeds in the world. Algal polysaccharides were prepared under four conditions, cold water, hot water,2% and0.5M NaOH solutions; and twenty four polysaccharides were successfully obtained, respectively. Their chemical properties, including contents of total sugar, protein and sulphate groups, and structural informations, including molecular weight, monosaccharides compositions and characteristic groups, were studied by chemical methods and1H-NMR and FTIR spectra analysis. Fucoidan is a sulfated polysaccharide from brown seaweeds, which has been reported with various bioactivities. We isolated and purified fucoidan fractions from extracts of Ascophyllum nodosum and Fucus vesiculosus. Their phosphorylated, oversulphated, desulphated and degraded derivatives were also prepared and the derivatives were indicated successfully processed on FT-IR spectra and characteristic chemical analysis.Glycoarrays technologies, an important tool in glycomics, have been developed as a top-leading technology to study the interactions of glycan-binding proteins with their glycan ligands. Islet-amyloid polypeptide (IAPP) is an important player in the formation of amyloid deposits and the progression of type2diabetes. Exploring a successful anti-amyloidogenic agent is another option to prevent diabetes mellitus. Fluoresceinisothiocyanate (FITC) or5-(((2-(Carbohydrazino)methyl)thio)acetyl)aminofluorescein (AF) labeled polysaccharides were printed on a nitrocellulose coated glass platform to create the glycoarrays and their IAPP binding abilities were screened as a high-throughput manner. FL3from F. lumbricalis and PP3from P. palmate showed the highest binding abilities on glycoarrays which suggested that these algal polysaccharides might show the optional application against type-2diabetes.Alpha-glucosidase is a key enzyme for carbohydrate digestion associated with type-2diabetes mellitus. Algal polysaccharides and their derivatives were then invested the inhibitory effects against a-glucosidase by spectrophotometrical method. Among them, AN1and AN4from A. nodosum, FV1and FV4from F. vesiculosus showed highest inhibition. Further studies showed that the inhibitory effects were caused by the polysacchardes not their binding proteins. Adipocyte tissue is the main target organ in response of insulin and plays a critical role in insulin resistance and type-2diabetes.3T3-L1preadipocyte cell lines are important in use to study the pathogenesis mechanism of insulin action and lipid-lowing in vitro. Algal polysaccharides and their derivatives were next studied on lipid accumulation in cultured3T3-L1adipocytes by measuring triglyceride (TG) contents and Oil Red O (ORO) staining as indicators. Treatment with PL2, PL3(from P. lanosa), FL3(from F. lumbricalis), PP2, PP3(from P. palmata) and most of fucoidan fractions decreased the lipid accumulation by ORO staining while FL2, FL3(from F. lumbricalis), AN2(from A. nodosum), and FV1(from F. vesiculosus) could reduce the TG content in3T3-L1adipocytes.Two families of transcription factors, CCAAT/enhancer binding protein (C/EBP) and peroxisome proliferator-activated receptor-Υ (PPARy), are induced early during adipocyte differentiation. By enzyme-lined immunosorbent assay (ELISA), algal polysaccharides FL3(from F. lumbricalis), AN2(from A. nodosum) and two fucoidan fractions, AN3F and FV3F, were invested to decrease the expression of PPARy protein.According to these results, we next focused on the effect of FL3, PP3, AN1, AN4, FV1, FV2, AN3F and FV3F against the early stage of3T3-L1adipogenesis study. AN3F showed the strongest suppression on PPARy and C/EBPβ,and the promotion on PPARa and C/EBPa in a dose-dependent manner, which suggested that it decreased the lipid accumulation in3T3-L1adipocytes through the effects on these PPARs and C/EBPs transcription factors and its anti-diabetic acitivity could be related to the MAPK signal involving many cytokines.In a conclusion, we successfully prepared24algal polysacchardes and45fucoidan derivatives from six kinds of seaweeds collected from Atlantic Canadian coast (including the commercial fucoidan and its derivatives). Their anti-diabetic activities were screened by glycoarrays technologies, enzymatic spectrophotomctrical assay, enzyme-lined immunosorbent assay and western blot analysis. Among them, AN3F showed the potential anti-type-2diabetes affection by suppression the transcription factors in adipogenesis. Although, further molecular mechanism of AN3F and animal studies remains to be elucidated, AN3F provided potential of a new target for anti-diabetes research.