| BackgroundLuo Han Shen is the root of the legume plant Ap iao s fo rtuneiM axim.,also known as taro,etc..Researches find that it is rich in essential amino acids,minerals, vitamins and other nutrients.Luo Han Shen has a long cultivation history in China, and it ever was documented as a herbal medicine,healing the toxification and swell.It has been regarded as a kind of functional food in popular,but there is no reports about its function and mechanism.Objectives1.To determine the concentration of total flavonoids,procyanidine and crude polysaccharide in Luo Han Shen and other four kinds of high carbohydrate food and compare the concentrations in the steamed food to the raw food in order to find the effect of steam process on these functional components.2.To measured the glycemic index(GI) of Luo Han Shen and pumpkin.3.To study the effect of Luo Han Shen on the blood glucose level of the diabetic model mice.Methods1.Determination of total flavonoids concentration:samples were prepared by ultrasonic extraction,standard curve was drew by Rutin and the concentrations of total flavonoids were determined by the adsorption chromatography method.2.Determination of procyanidine concentration:standard curve was drew by grape seed extract and the concentrations of procyanidine were determined by the Colorimetry with Ferric Ions as Catalysis Agent method.3.Determination of crude polysaccharide concentration:standard curve was drew by dextran and the concentrations of crude polysaccharide were determined of by the Phenol-sulfuric acid method.4.Determination of glycemic index:10 healthy volunteers were involved in this study,half men and women,20 to 25 years old.This paper applies cross-over experiment method.Ten healthy subjects were involved in this study.They consumed three kinds of carbohydrate foods:glucose powder,Luo Han Shen and pumpkin respectively in three times and each interval time of different food is 72h.The fasting blood glucose level and the blood glucose levels of 15,30,45,60,90 and 120min after consumption of test materials were determined and the glucose-response curves were drawn.The GI values of other high-carbohydrate foods referred to Chinese Food Composition Table 2002.5.124 male Kunming mice(28～32g)were involved in this experiment.Alloxan (200mg/Kg) was injected into rats by intraperitoneal injection to establish the diabetic model once a day,total two days.The fasting blood glucose of mice were tested 5 days later,greater than 10.0mmol/L and less than 25mmol/L as the diabetic model mice.The model mice were divided randomly into four groups based on the fasting blood glucose level(the model control group,the low-dose group,the middle-dose group,the high-dose group),12 mice each group,given basic diet and diets containing 5%,10%,20%Luo Han Shen respectively.24 normal mice were divided randomly into two groups based on the fasting blood glucose level(the control group and the positive control group),12 mice each group,given basic diet and diet containing 20%Luo Han Shen respectively.The blood glucose and glucose tolerance were tested 6 weeks later.Results1.The concentrations of total flavonoids in the five high carbohydrate are 6.773±0.6939,0.420±0.0924,0.254±0.0356,0.773±0.0325 and 0.451±0.1742 mg/100g,the concentrations of procyanidine are 4.972±0.1358,0.012±0.4145, 7.043±0.51141,3.222±0.4381 and 0.010±0.1374 mg/100g,and the concentrations of crude polysaccharide are 0.506±0.0361,4.492±0.2003,8.126±0.5976,3.659±1.4065 and 18.216±0.3784 mg/100g,respectively.The concentration of procyanidine of Luo Han Shen was higher than sweet potato and Chinese yam(p＜0.05).The concentration of crude polysaccharide was lower than Chinese yam(p＜0.05).2.After steamed,the concentrations of total flavonoids and crude polysaccharide of five high carbohydrate food reduced at different degree,and the concentration of procyanidine can not be test.The lost rate order of the total flavonoids was:Potato＞Chinese yam＞Luo Han Shen＞sweet potato＞taro,and the lost rate of the crude polysaccharide was:Luo Han Shen＞taro＞Potato＞Chinese yam＞sweet potato.3.The GI value of Luo Han Shen and pumpkin was 48.87±0.055,78.75±0.105 respectively,regarding glucose powder as 100.The added area under the glucose-response curve and the peak level of Luo Han Shen were significantly lower than those of glucose powder and pumpkin(p＜0.05).The added area under the glucose-response curve of pumpkin was lower than that of glucose powder(p＜0.05).4.The weights of mice in the control group and positive control group increased each week,those in the model and low-dose group decreased and those in the middle-dose and high-dose group firstly decreased and then increased.The fasting blood glucose level of the high-dose group mice reduced insignificantly after training (P＜0.05),and was also lower than that of the model control group after training (P＜0.05).Compared to the model control group and the low-dose group,the blood glucose level at 0,0.5,2h and the area under the blood glucose-response curve of the high-dose group were significantly lower.Compared to the model control,the blood glucose level at 0.5h of the middle-dose group was significantly lower(P＜0.05).Conclusions1.The concentrations of total flavonoids,procyanidine and crude polysaccharide in Luo Han Shen are 0.51±0.036,4.97±0.14,6.77±0.69mg/100g,respectively.The concentration of procyanidine of Luo Han Shen was higher than sweet potato and Chinese yam(p＜0.05).2.After steamed,procyanidine in all samples were almost destroyed,the concentrations of crude polysaccharide decreased significantly(p＜0.05),and the concentrations of total flavonoids decreased at different degree according to the different foods.3.The GI value of Luo Han Shen and pumpkin was 48.87,belonging to the lower GI food,and was lower than that of pumpkin(78.75).4.The postprandial blood glucose level of Luo Han Shen is lower than that of pumpkin and other high carbohydrate foods.The explanation of the difference may be that the proportion of resistant starch in Luo Han Shen starch is higher(77.31%).5.Luo Han Shen can reduce the blood glucose level and improve the glucose tolerance of diabetic model mice.
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