| AIM: Polydatin is one of the effective ingredients extracted from Poligonum Cuspidatum Sieb. et Zuec. It can be used to protect myocardium, enhance microcirculation and inhibit the aggregation of platelets. It also can prevent endotoxin shock, 1ower lipid and resist superoxidation of lipid. The purpose of this study was to reveal the absorption and metabolism of polydatin in the rats to provide guidance for its pharmacological and toxicological study and clinical practice.METHODS: 1. Liquid-liquid extraction was adopted to dispose plasma samples, and LC/MS/MS was used to detect polydatin and its metabolite in biological specimen by means of MRM (ESI-). 2. 0.5% CMC-Na was applied for polydatin suspension, and polydatin with different doses (50, 100 and 300mg/kg) was administered to SD rats by gavage. After administration, the SD rats were anesthetized with ether, and the blood samples were collected at different time point(10, 20, 30, 60, 120, 240, 360, 480, 720, 960, 1440min) via inferior vena cave (heparin anticoagulation). Then the plasma was separated by centrifugation for 10 min. (1) 100μL internal standard solution(400 ng/mL, genistein) was added to 0.25mL plasma. The samples were extracted twice with 2.0mL acetidin. The organic phase was transferred to a clean tube and evaporated to dryness at 50℃under a gentle stream of nitrogen in the ventilation cabinet. The residue was dissolved in 50μL of methanol and 10μL was taken for LC/MS/MS analysis. (2) 0.2mL glucuronidase solution(2000 U/mL)was added to 0.25mL plasma and incubated at 37℃for 24h in water bath shake. The sample was treated detected according to step (1). 3. The model of intestinal tract perfusion in situ was set up. The intestina parva of 10cm in length from the point 5cm below the duodenum was perfused by intubation, and then the perfusate samples were collected at different points(10, 20, 30, 40, 50, 60min) via portal vein. The concentration of resveratrol and polydatin were detected by the method of LC/MS/MS. At the same time, the sample was treated with glucuronidase to detect the concentration of glucuronidated resveratrol and polydatin. 4. The model of liver perfusion in situ was set up.The drug was poured into portal vein, and then the perfusate samples were collected at different points(10, 20, 30, 40, 50, 60min) via inferior vena cave. The concentration of resveratrol and polydatin were detected by the method of LC/MS/MS. At the same time, the sample was treated with glucuronidase to detect the concentration of glucuronidated resveratrol and polydatin.RESULTS: 1.Take the ratio of peak area of polydatin and resveratrol to peak area of internal standard genistein separately for Y-axis, and the concentration of polydatin and resveratrol for X-axis to built the working curve .The typical regression equation to assay the concentration of the polydatin in the rat plasma was Y = 0.0543X-0.032,γ=0.9999,n=6. The linear range was 0.4-200ng/mL and the fixed lower quantity was 0.4ng/mL. The typical regression equation to assay the concentration of the resveratrol in the rat plasma was Y =0.0366X+0.1138,γ=0.9999,n=6. The linear range was 0.4-200ng/mL and the fixed lower quantity was 0.4ng/mL. 2. Polydatin was quickly absorbed and biotransformed in SD rats, and produced resveratrol, glucuronidated resveratrol and glucuronidated polydatin, etc. After the SD rats were given at the dose of 50, 100 and 300mg/kg by gavage, the area under curve (AUC)of polydatin were 53574, 85970, 228245 ng?min/mL, and its half life was 120, 185, 285min respectively. The AUC of resveratrol were 77000, 123000, 521000 ng?min/mL, and its half life was 107, 301, 425min respectively. The AUC of glucuronidated resveratrol were 1888000, 4560000, 11883000 ng?min/mL, and its half life was 213, 496, 545min respectively. After the polydatin was administered to rats at the dose of 100, 300mg/kg by gavage, the AUC of glucuronidated polydatin were 268922, 1507200 ng?min/mL, and its half life was 222, 202min respectively. 3. Polydatin with the dose of 50μmol/L was given to rats by intestinal tract perfusion, and polydatin was quickly absorbed and biotransformed , and produced resveratrol, glucuronidatied resveratrol, glucuronidated polydatin, etc. After 10min, the amount of resveratrol in blood was 1.7 times as much as that of polydatin; the amount of glucuronidated polydatin in blood was 4.6 times as much as that of polydatin; the amount of glucuronidated resveratrol in blood was 1.6 times as much as that of resveratrol. 4. Polydatin with the dose of 5μmol/L was given to rats by liver perfusion, and polydatin was quickly biotransformed , and produced glucuronidated resveratrol and glucuronidated polydatin. After 10min, the amount of glucuronidated polydatin in blood was 0.6 times as much as that of polydatin; the amount of glucuronidated resveratrol in blood was 5.7 times as much as that of resveratrol. CONCLUSION: 1. The assay method was proved to be accurate, sensitive and suitable for pharmacokinetic study. 2. Polydatin with different doses (50, 100, 300mg/kg) was administered to rats by gavage and absorbed into blood quickly. The quantity of polydatin in blood was positively correlated with the dose of polydatin. Polydatin was biotransformed into resveratrol, glucuronidated resveratrol and glucuronidated polydatin. The amount of metabolite was positively correlated with the dose of polydatin. 3. In intestinal tract, polydatin was biotransformed into resveratrol, glucuronidated resveratrol and glucuronidated polydatin, in which glucuronidation of polydatin was the main form. 4. In liver, polydatin was biotransformed into glucuronidated resveratrol and glucuronidated polydatin, in which glucuronidated resveratrol was the main form. Resveratrol was biotransformed into glucuronidated resveratro in liver. 5. Compared to resveratrol, oral administration of polydatin was not only easy to be absorbed, but also could be biotransformed to a great amount of active metabolite (resveratrol), therefore, polydatin has superiority to resveratrol in the prevention and cure of diseases.
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