Preparation Of Black Sesame Pigment And Its Anti-diabetic Activity

Diabetes and its complications has been a serious threat to human health and life.Black sesame melanin is a natural pigment derived from the black sesame seed coat,which has many biological activities such as anti-oxidation,anti-tumor and so on.However,there is not clear on the anti-diabetic activity of black sesame pigment.In this study,taking the fired black sesame pigment(FBSP)and black sesame pigment(BSP)as the research objects.To comprehensive system research on the hypoglycemic and hypolipidemic activities of mice with type 2 diabetes mellitus(T2DM),to clarify their anti-diabetic activity and mechanism.The effects of BSP and FBSP on the slow development of diabetes and its complications were evaluated.The main results are as follows:1.Melanin was extracted by alkali-soluble acid precipitation method.The optimum pH of the extraction process was found to be 3 by single factor experiments.The yields of BSP and FBSP were 22.97% and 10.60%,respectively.Further,the BSP and FBSP extracted by UV and IR spectroscopy are all melanin.2.The in vitro digestive experiments of BSP and FBSP in the human digestion and the hypoglycemic activity of the products after digestion.Itwas found that BSP and FBSP were mainly digested in the small intestine,and the products after digestion in the small intestine showed a certain inhibition of ?-glucosidase and ?-amylase activity,in which ?-glucosidase inhibition rate was respectively 45.22±1.15% and 30.28±0.50%,the?-glucosidase inhibition rates were 49.13±3.90% and 54.34±4.16%,respectively.3.Study the hypoglycemic and hypolipidemic activities of BSP and FBSP on T2 DM mice.The results showed BSP and BSP could decrease blood glucose level,improve polydipsia,polyphagia and weight loss in diabetic mice.Furthermore,BSP and BSP could significantly alleviate the liver and kidney swelling caused by liver and kidney damage.Compared with T2 DM group,the survival rate of mice in BSP-H and FBSP-H(800mg/kg/d)were improve 33.4% and 50%,respectively.BSP and BSP could significantly improve dyslipidemia in T2 DM mice.The mice plasma TC and TG levels were decreased dramatically after administration of BSP or FBSP for 4 weeks.4.The anti-diabetic mechanism of BSP and FBSP was examined from the level of oxidation in vivo.It was found that BSP and FBSP can significantly increase the activities of antioxidant enzymes GSH-Px and SOD in T2 DM mice,and reduce the content of lipid peroxide MDA,and can significantly reduce the plasma ALT,AST,BUN and Scr levels inT2 DM mice.The HE pathological sections of liver and kidney showed obvious improvement of liver and kidney injury in BSP and FBSP groups.5.The mechanism of anti-diabetes of BSP and FBSP was further studied by detecting the expression of genes and proteins related to glycolipid metabolism in the liver.The results showed BSP and FBSP could significantly reduce the gene expression levels of G6 Pase,PECPK as well as TGF-?1 mRNA,and significantly increase the gene expression levels of PPAR? as well as SIRT1 mRNA.The protein expression levels of p-AMPK/AMPK,PPAR?,PPAR? as well as PGC-?1 in BSP and FBSP groups were significantly up.In a word,these results showed that BSP and FBSP have positive regulation of oxidative stress in T2 DM mice,and can alleviate liver and kidney damage caused by diabetes and delay diabetes,especially FBSP.The mechanism may be associated with that activating the AMPK/SIRT1/PGC1,AMPK/PPAR? and PPAR?/SIRT1/AMPK pathways to regulate the glucose and lipid metabolism,improve insulin resistance and alleviate the symptoms of diabetic complications in T2 DM mice.The protection mechanism remains to be further studied.