Effectt Of Tartary Buckwheat On Hyperlipidemic Rats And Its Mechanism

ObjectiveCardiovascular disease is the first chronic diseases which causes death, lipid metabolism disorder which represented as hyperlipidemia is an important incentive for cardiovascular disease, so controlling the occurrence of hyperlipidemia for the prevention of cardiovascular disease is of great significance. Tartary buckwheat is one of our traditional cereal, contains a lot of rutin, quercetin and other flavonoids, which are considered to have the role of lipid-lowering, hypoglycemic, anti-oxidation. We get buckwheat flavonoids extracted from tartary buckwheat from Liangshan, establish a HPLC method of determination rutin and quercetin in serum and tissues, in addition to research total flavonoids of buckwheat and tartary buckwheat’s lipid-lowering effect on experimental hyperlipemia diseased rats and its mechanism, providing a theoretical basis for the development of tartary buckwheat foods.Methods1.90% ethanol,65℃ water bath for preparing buckwheat flavonoids. Using ODS-SPC18 chromatography column (4.6 mm x 250 mm,5μm), acetonitrile (B) and 0.5% phosphate buffer (A) as the mobile phase with gradient elution (25% B 0～6min,25%～50%B 6-10min,50%B 10-17min,50%-25%B 17-20min,25%B 20-25min); flow rate was 1ml/min; column temperature was 40℃, detection wavelength was 360 nm, measure rutin and quercetin in serum and tissues.2. SPF level SD adult male rats 70,10 fed the basal diet as control group, and the remaining 60 fed with a high-fat diet produce hyperlipidemia model. A week later, hyperlipidemia model randomly divided into six groups by serum TC and weight: model group、high dose tartary buckwheat flavonoids、low dose tartary buckwheat flavonoids、drug control、high dose tartary buckwheat、low dose tartary buckwheat. 7 groups of rats were treated as follows:drug control group by intragastric administration of 2mg/kg·bw simvastatin tablets (high fat diet), low、high dose tartary buckwheat flavonoids group by intragastric administration of 91、300mg/kg ·bw buckwheat flavonoids (high fat diet),control group(basal diet)、model group (high fat diet) gavage equal amounts distilled water 10 ml/kg·bw distilled water. High dose tartary buckwheat fed high-fat diet containing 10% buckwheat, low dose tartary buckwheat group and 3.33% buckwheat fat diet, Continuous 4 w. Body weight was observed weekly and after experiment blood was taken from the rats heart, Centrifugal and separation serum, determine serum TG, TC, HDL-C, LDL-C. The liver was taken and weighed, part of the liver tissue was specimened for homogenizing to measuring liver TG、TC. Liver fat and liver HMG-CoA reductase (HMG-CoA reductase), cholesterol 7a-hydroxylase (cholesterol 7a-hydroxylase, CYP7A1) and low density lipoprotein receptor (low density lipoprotein receptor, LDL-R) expression levels by RT-PCR.Results1. According HPLC, buckwheat contains about 1.8 percent of rutin, about 0.2% of quercetin; buckwheat flavonoids including 60% of rutin,6.67% of quercetin. The method had good linearity with the concentration ranges of 0.08-25μg/ml and 0.016-10μg/m for rutin and quercetin in serum, the correlation coefficient (r) was 0.9999; the detection limits of rutin and quercetin were 0.016μg/ml and 0.004μg/ml; interday precision (RSD,%) were less than 7.4% and 8.1%, intraday precision (RSD,%) were less than 9.1% and 9.0%. And also had good linearity with the concentration ranges of 0.05-8μg/ml for rutin and quercetin in tissues, the correlation coefficient (r) were 0.9999, the detection limits of rutin and quercetin of liver were 0.012μg/ml and 0.004μg/ml, interday precision (RSD,%) were less than 7.9% and 8.9% and intraday precision (RSD,%) were less than 8.9% and 7.2%, the detection limits of rutin and quercetin of kidney and small intestine were all 0.020μg/ml; The recoveries of rutin and quercetin in serum and liver were more than 72%.2. After the end of the experiment, compared with the normal control group, the weight gain, liver index, serum total cholesterol (TC), serum triglyceride (TG), low-density lipoprotein (LDL-C), liver TG rats in the model group were significantly increased (P<0.05). Compared with the model group, each dose group of tartary buckwheat flavonoids and tartary buckwheat of rats, serum TG、TC、 LDL-C and liver TG value decreased, low-density lipoprotein (HDL-C) increased, the differences were significant statistically (P<0.05). Compared with normal control group, model group was significantly increased liver HMG-CoA mRNA expression levels, significantly reduced liver CYP7A1, LDL-R mRNA expression level (P<0.05); compared with the model group, each tartary buckwheat flavonoids and tartary buckwheat group and drug control group inhibiting the expression of HMG-CoA and increase CYP7A1. LDL-R mRNA expression level (P<0.05).Conclusion1. The method is sensitive、reproducible and good、simple、fast and can be used in serum and tissues of rutin and quercetin negligent analysis and determination,2. Buckwheat flavonoids do have the exact role of lowering lipid, its mechanism may be related to inhibiting HMG-CoA, increasing CYP7A1, LDL-R mRNA expression levels.