Research On Hypoglycemic Activity And Mechanism Of Phenolic Compound In Whole Grain Brown Rice

Diabetes Mellitus(DM)is a systemic metabolic disorder disease that is one of the world's biggest health problems and has seriously harmed human life and health.Epidemiological and clinical studies have shown that eating whole grains can effectively reduce the incidence of hyperglycemia and hyperlipidemia,and can prevent a variety of chronic diseases,among which phytochemicals such as phenolic substances are the main active substances of whole grains.Therefore,it is very important to study its hypoglycemic mechanism and further develop and utilize whole grain bioactive substances.In recent years,studies have shown that whole grains have a preventive and mitigating effect on chronic diseases,and the health function of whole grain brown rice has gradually gained widespread attention and recognition.However,brown rice is generally processed and eaten.The effect of processing methods on the physiological activity of brown rice has rarely been studied.The research on brown rice is generally focused on the physiological activity of rice bran.There is little research on the physiological activity of whole grain brown rice or brown rice and rice bran mixture.Therefore,four brown rice varieties were selected in this study.The differences in the content and composition of phenolic compounds in different varieties of brown rice were compared.The chemical and cellular hypoglycemic activities of whole grain brown rice products with different processing methods were analyzed.Blood glucose,enzyme activity levels and genes were also analyzed.As well as the expression level of protein levels,etc.,the activity of hypoglycemic in whole grain brown rice products and the main mechanism of action were evaluated.The main findings are as follows:(1)Determination of phenolic substances in different brown rice varieties.The results showed that the total phenolic acidsand flavonoids in brown rice extracts were mostly in the form of bound state.The total phenolic content of the four brown rice varieties ranged from 234.7-2276.03 mg GAE/100 g DW,and the total flavonoid content ranged from 154.09 to 235.58 mg CE/100 g DW.The content of free phenolic acidsand flavonoids in Hangxiangnuo was the highest;the content of total phenolic acidsand the content of bound phenolic acidsand flavonoids in Longjing 31 were the highest.The phenolic monomer substances in the brown rice extract include ferulic acid,p-coumaric acid,p-hydroxybenzoic acid and caffeic acid,and the ferulic acid content is the highest.(2)Determination of antioxidant activity of different brown rice varieties.The antioxidant capacity of the extracts of four brown rice varieties was determined by PSC and CAA.The results showed that the antioxidant activities of the varieties varied greatly and the antioxidant properties of the bound extracts were generally higher than the free extracts.The PSC value of the bound extract of Longjing 31 was the highest,and the free extract of Hangxiangnuo was the highest.The free and bound fractions of Longjing 31 had the largest cellular antioxidant activity(CAA)value in no PBS protocol.But in PBS protocol,CAA value were highest in free fraction of Hangxiangnuo and bound fraction of Longjing 31.(3)Determination of the content of brown rice phenols and bioavailability of different processing methods.The brown rice,the brown rice after the cooking and extrusion treatment,and the whole grain extrudate are chemically extracted,and the results showed that the cooking and extrusion processing of brown rice reduced the content of polyphenol flavonoids.Whole grain extrudate retained the content of phenolic substances.After in vitro simulated digestion,and it was found that the bioavailability of brown rice was significantly lower than that of the other three samples.(4)Chemical methods for the detection of antioxidant,hypoglycemic activity and hypoglycemic studies in the IR-L02 model.The antioxidative and hypoglycemic activities of the four samples were determined by chemical method.It was found that the antioxidant activity and the inhibitory activities against ?-amylase and ?-glucosidase of phenolic extracts did not change significantly after brown rice cooking and extrusion,but the antioxidant capacity and the inhibitory activity of ?-glucosidase of the phenolic extract of the whole grain extrudate increased.Based on the IR-L02 model,the glucose consumption rate of phenolic substances in four samples was studied.After treatment with four kinds of samples,the glucose consumption rate in insulin resistant cells was significantly improved,and the improvement ranged from 12.04% to 33.41%,the whole grain extrudate increased the glucose consumption rate of insulin resistant significantly higher than the other three samples.(5)The db/db diabetic mouse model was used to study the hypoglycemic effect and mechanism of whole grain extrudate,including 97% brown rice and 3% defatted rice bran(BRD).Db/db diabetic mice were used as model mice to prepare feeds with different raw material additions.The changes of disease indicators in db/db diabetic mice were detected,and the mechanism of action was further studied at the gene and protein levels.It was found that extrusion of BRD can improve hyperglycemia,lower liver index and lower glucose tolerance in db/db diabetic mice.It can also improve blood lipid levels,lower serum insulin levels,improve insulin resistance,and liver tissue.The pathological symptoms have been alleviated.Studies on its mechanism of action have found that the mechanism by BRD improve the condition of db/db diabetic mice is multi-targeted and multi-channel.Therefore,this study explored the hypoglycemic bioactivity of whole grain brown rice by in vivo and in vitro experiments and studied its main mechanism,aiming to promote the application of whole grain foods.