The Anti-hyperglycemic Effects Of Plantain And Its Mechanism

The incidence and prevalence of the diabetes continues to rise globally,specifically in youth.It is of substantial significance to explore the safe and low-cost anti-diabetic dietary supplements from biological resources.Bananas are characteristic fruits of tropical and subtropical areas,which have the advantages of wide planting area and high yield.Unripe banana,rich in resistant starch and dietary fiber,displays an important role in anti-hyperglycemic efficacy.Therefore,the anti-diabetic activities of unripe plantain(Musa AAB group,Plantain AAB group)in rats with diabetes induced by high-sugar and high-fat diet combined with streptozotocin(STZ)and the potential mechanisms in glucolipid metabolism indicators,hormones,gut microbiota,short-chain fatty acids and bile acids were investigated in this article.The normal control group(NC),the normal control group feed with high dose of plantain(NH),the diabetes mellitus group(DM)and the intervention groups of low(LP),medium(MP)and high(HP)doses of unripe plantain flour were set up.The intragastric doses of intervention groups were 1,2,4 g/(kg·BW·d)respectively.The present study aimed to provide basic data for the development of anti-hyperglycemic supplements or functional foods.The main contents and results are listed as follows:(1)The anti-hyperglycemic effect and ameliorative effect on liver and renal damage of plantain were studied in diabetic rat induced by high-sugar and high-fat diet combined with STZ were studied.The results showed that,compared with the DM group,the glucose tolerance of MP group was improved by 8.33%.Plantain intervention reduced the fasting blood glucose at the initial stage of intervention(1-2 weeks),compared with the DM group,the low-dose,medium-dose and high-dose groups(which referred as the three dose groups in follows)were reduced by 6.25%,7.95% and 12.30%(the first week),3.84%,5.17% and10.68%(the second week),respectively.Plantain ameliorated the typical symptoms of polyphagia,polydipsia,polyuria,and weight loss caused by diabetes.Particularly,the intervention of plantain repaired the damage of liver and renal function,and inhibited the enlargement of liver and spleen.It reduced the fat accumulation in liver and renal tissue in diabetic rats.Moreover,the concentrations of serum alanine aminotransferase(ALT),aspartate aminotransferase(AST)and urea(UREA)were decreased.In ALT and AST,the three dose groups decreased by 58.68%,58.91% and 40.05%;75.65%,75.25% and 58.51%,respectively.In respect of UREA,the LP and MP groups decreased by 12.71% and 11.97%,respectively.In addition,the ratio of albumin and globulin(ALB/GLB)and the concentrations of creatinine(CREA)were increased in plantain intervention groups.The ratio of albumin and globulin in MP and HP groups was increased by 14.29% and 12.99%,respectively.CREA content in HP group was increased by 15.68%.(2)The potential anti-hyperglycemic mechanism of plantain by glucolipid metabolism,insulin resistance and hormone regulation were further analyzed.The results were as follows.On one hand,plantain mitigated dyslipidemia in diabetic rats by reducing serum total triglyceride(TG),total cholesterol(TC),low-density lipoprotein cholesterol(LDL)and free fatty acid(FFA)content.In terms of TG,the three dose groups decreased 59.06%,62.32%and 50.12%,respectively.TC was reduced by 35.53% and 55.23% in MP and HP groups,respectively.LDL was reduced by 41.81% in MP and 65.67% in HP.On the other hand,plantain reduced the serum glucose of diabetic rats by 10.70%,10.19% and 13.94%,respectively,and promoted the synthesis of liver glycogen(34.52%,26.22% and 59.02%,respectively),as well as regulated glucose metabolism disorders in diabetic rats.In addition,plantain not only reduced the levels of serum insulin,C-peptide,amylin and glucagon-like peptide-1(GLP-1),thereby protecting the islet function,but also improved the diabetes symptoms by reducing insulin resistance and increasing insulin sensitivity.Regarding hormone regulation,firstly,plantain intervention reduced the levels of glucagon(14.47%,28.00% and 40.89%,respectively),epinephrine,thyroxine and ghrelin,and increased the levels of glucocorticoid and growth hormone to inhibit liver glycogenolysis;secondly,plantain intervention reduced the abnormally elevated leptin levels,also increased the levels of adiponectin(9.71%,81.75%,and 133.51%,respectively),in order to enhance fatty acid oxidation,thereby reducing lipid profile.(3)The effects of plantain on the composition and abundance of intestinal bacteria in diabetic rats was studied by the 16 S r RNA gene sequencing.The results showed that the intake of plantain reversed the structure and relative abundance of the intestinal bacteria.At the phylum level,plantain intervention reduced the relative abundance of the Proteobacteria;at the genus level,plantain intervention promoted the growths of the beneficial bacteria,such as Lactobacillus,Bifidobacterium,Blautia,Akkermansia,Eubacterium,Lachnoclostridium and Butyricicoccus,while reduced the relative abundance of harmful bacteria,such as Romboutsia and Allobaculum.The effects of plantain on the concentrations of short-chain fatty acids and bile acids in the fecal sample were analyzed by gas chromatography(GC)and high performance liquid chromatograph mass spectrometer(HPLC-MS).The results were as follows.In terms of short-chain fatty acids,the diabetes had a greater impact on n-butyric acid and n-valeric acid,by reducing their content.Furthermore,plantain intervention significantly increased the production of acetic acid(49.34% and 59.43% in MP and HP group),propionic acid(12.33%and 20.49% in MP and HP group),n-butyric acid(20.59% and 18.18% in MP and HP group),iso-butyric acid(11.67% in MP group)and n-valeric acid(11.67% in HP group).In terms of bile acids,plantain administration not only reduced the content of hydrophobic bile acids such as cholic acid(CA)and deoxycholic acid(DCA),but also increased the content of hydrophilic bile acids,such as ursodeoxycholic acid(UDCA)and tauroursodeoxycholic acid(TUDCA).Additionally,plantain intervention promoted the excretion of secondary bile acid lithocholic acid(LCA),thereby reducing serum TC content.Spearman correlation analysis implied that the improvement of diabetes condition was closely related to the good changes of intestinal flora.Plantain increased the relative abundance of Bifidobacterium in order to increase the contents of acetic acid,propionic acid,butyric acid and valerate,at the same time increased the relative abundance of Akkermansia to increase the contents of acetic acid,butyric acid,valerate,taurodeoxycholic acid and urocholic acid.The contents of liver glycogen,glucocorticoid and adiponectin were increased by increasing the relative abundance of Blautia and Akkermansia,while the contents of GLU,TC,FFA,ALT,AST,insulin,GLP-1,glucagon and leptin were decreased.In summary,the potential mechanisms of anti-hyperglycemic by plantain was surmised as:(1)plantain influenced the hormone secretion pathway,by reducing abnormally elevated levels of hormones such as insulin,glucagon and leptin,and increasing glucocorticoid and adiponectin,thereby improving glucolipid metabolism and insulin resistance in diabetic rats;(2)plantain regulated the gut structure of microbiota,by increasing the relative abundance of beneficial bacteria such as Bifidobacterium,Blautia and Akkermania,reducing the relative abundance of Romboutsia and Allobaculum,thereby improving the metabolism of short-chain fatty acids and bile acids,and benefitting for the biochemical indicators related to diabetes.