Investigation Of Anti-diabetic Mechanism Of Maize Bran Feruloylated Oligosaccharides On Diabetic Rats

Type 2 diabetes mellitus is a common metabolic disease with high fatality rate and its morbidity increased in each year.Due to side-effects of oral antidiabetic medicines,natural products and extracts of traditional Chinese medicines with high efficiency and low toxicity for prophylaxis and treatment of diabetes mellitus have been a research hot spot.Feruloylated oligosaccharides are esterification products of xylooligosaccharide and ferulic acid;in which,ferulic acid is an active ingredient in the traditional Chinese medicine,including Angelica sinensis and Ligusticum wallichii.Therefore,feruloylated oligosaccharides have nutritional and medical functions of both ferulic acid and xylooligosaccharides,and show much better solubility in water and can maintain higher concentration in plasma than ferulic acid.The first feruloylated oligosaccharides product was approved to be used as a novel food by the United States Food and Drug Administration(US FDA)in 2010.The highly yielded maize bran was used as the raw materials to obtain the feruloylated oligosaccharides,to investigate the effects and mechanisms of preventive and therapeutic effects in diabetic rats.It is the first time to investigate the anti-diabetic mechanism of maize bran feruloylated oligosaccharides in diabetic rats both in vivo and in vitro.In this research,we established a reaction system to simulate the formation process of advanced glycation end products(AGEs)in vitro.Maize bran feruloylated oligosaccharides were incubated in the reaction system under 37 ? for 7 days.A fluorescence spectrophotometry was used to determine the level of the fluorescence of AGEs and protein oxidation.And the concentration of dicarbonyl compounds were determined by a high performance liquid chromatography.Maize bran feruloylated oligosaccharides were also added into the dough of biscuits and were baked under 190 ? for 8 min.The color and texture of biscuits were measured by a colorimeter and a texture analyzer,respectively.Antioxidation capacity of water extracts of biscuits was evaluated based on free radical scavenging capacity and reducing power.A fluorescence spectrophotometry was used to determine the level of the fluorescence of AGEs and protein oxidation in biscuits.The p H of water extracts from biscuit was measured by a p H meter,and the concentration of dicarbonyl compounds and ferulic acid were determined by high performance liquid chromatography.After administration with maize bran feruloylated oligosaccharides,we observed the glucose and lipid metabolism,antioxidant activity and alteration of intestinal bacterial flora in healthy rats.We also investigated the therapeutic effect of maize bran feruloylated oligosaccharides on STZ diabetic rats.Several outcome variables were measured including the body weight and water intake,glucose and lipid metabolism,protection effects against hepatocyte,myocardial and abdominal aorta injuries,antiglycation and antioxidant effects in tissues and plasma.To investigate the preventive and therapeutic effects and mechanism of feruloylated oligosaccharides on diabetes mellitus,maize bran,a high yield but low recycling rate by-product,was chosen as the raw material for extraction of feruloylated oligosaccharides.In this research,in vitro and in vivo studies are combined to investigate the anti-diabetic effects of maize bran feruloylated oligosaccharides by different detection techniques,such as high performance liquid chromatography,fluorescence spectrophotometry,Western Blot and 16 s r RNA.The results indicated that maize bran feruloylated oligosaccharides can effectively control the development of diabetes mellitus,such as prevent the polydipsia,abnormalities of glucose and lipid metabolism,heart and liver damage and insulin resistance,from the aspects of antioxidative stress,antiglycation,intestinal microecology regulation and vessel protection.These results provide valuable evidences and clues for the theoretical basis of traditional Chinese medicine in prevention and treatment of type 2 diabetes mellitus,and lay an important foundation for the research of functional food ingredients.