| Diabetes is harmful to the health of human.At present,most of the hypoglycemic drugs are synthesized by chemical methods.The pharmacodynamics of diabetes mellitus are remarkable but have many negative effects.Extracting natural active ingredients with hypoglycemic function from the plant has become a research hotspot in recent years.The okra was a kind of nutritious vegetables.There were many studies on the functional components of okra,but few studies on the hypoglycemic activity of its flavonoids.In this study,the flavonoids of okra were extracted,separated and purified.The hypoglycemic activities of flavonoids from ok:ra were studied in vitro and in vivo.The main results were as follows.Firstly,the effects of four single-factor conditions on ultrasonic-assisted extraction of total flavonoids from okra were studied.Under the ultrasonic power of 500 W and extraction temperature of 40℃,the optimum extraction conditions were designed by orthogonal experiment.The optimum conditions were ethanol concentration of 70%,extraction time of 40 min,extraction time of twice,solid-liquid ratio of 1:35(g/mL).The highest yield of flavonoids with optimum conditions was 1.73%.Fat-soluble flavonoids and water-soluble flavonoids were obtained with extraction by alcohol and separation by ethyl acetate from okra.With comparing the adsorption and desorption abilities of six macroporous adsorbents,D101 macroporous adsorbent resin was selected to purify Aqueous flavones of okra.The recovery rate of Aqueous flavonoids was 76.83%when the desorption solution of 30%ethanol and the sample concentration of 6.14%.In these conditions,the content of flavonoids was 41.23%,which increased to 6.71 times.The two monomers were obtained from the flavonoids of okra with ethyl acetate phase separated silica gel coltumn.The preliminary analysis of HQ-2 was based on 2-phenylchromone as mother nucleus by NMR.The inhibition on alpha-glucosidase of water-soluble flavones from okra was studied in vitro.Firstly,the inhibitory activities on alpha-glucosidase of four different purities of okra flavonoids and acarbose with concentration of 0.3 mg/mL were studied.The inhibitory rates were 30.72%,39.76%,35.54%,45.78%and 49.40%,respectively.It could be seen that besides acarbose,the flavonoids from okra purif6ed by D101 macroporous resin have the best inhibition on alpha-glucosidase.The inhibition on alpha-glucosidase has dose-dependence when the concentration range of 0.1 mg/mL-1 mg/mL.When the concentration was 1 mg/mL,the inhibition rate was 86.75%,and the IC50 was 3.87 mg/mL.Finally,the diabetic model of mice was established by STZ induction to study the hypoglycemic effect of okra flavone purified by macroporous resin.After oral administration for five weeks by okra flavonoids at high-doses,middle-doses and low-doses,the physiological and biochemical indexes of mice were measured and the liver,kidney tissue section were observed.The results showed that okra flavonoids could effectively reduce the blood sugar value of mice to improve the ability of sugar tolerance.It also can significantly reduce the serum levels of TG,TC and LDL-C,increase the levels of HDL-C and insulin in diabetic mice to improve the disorder of lipid metabolism in diabetic mice and repair the damaged islets. |
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