Effect of hydrolysis process on quercetin content in Tartary buckwheat extract and its pharmacokinetics

Objective:To investigate the effect of hydrolysis process on quercetin content in Tartary Buckwheat extract and explore the acid hydrolysis influence on absorption of rutin and quercetin. Methods:Hydrochloric acid percentage, hydrolysis time, ethanol percentage and hydrolysis temperature were used to design a four-factor and three-level orthogonal test to optimize the acid hydrolysis process of rutin to quercertin, and hydrolyzate samples 1, 2, 3, 4 with different quercetin contents were prepared at 1, 2, 4, 6 h by this process. After oral administration of tartary buckwheat extract and hydrolysis samples (200 mg/kg), the blood samples were collected at the given time points. The concentration of quercetin was determined by HPLC, and the main pharmacokinetic parameters were calculated by DAS 2.0 software package. Results:The optimum parameters of rutin acid hydrolysis:The percentage of hydrochloric acid content, hydrolysis time, ethanol concentration and hydrolysis temperature were 0.91%, 6 h, 50% and 70℃, respectively. And 64.11% of rutin was hydrolyzed into quercetin under this process conditions. The AUC_0-t of Tartary buckwheat extract, hydrolyzate samples 1, 2, 3and 4 equaled (17.604±5.422), (42.175±9.435), (87.917±19.347), (116.706±46.256) and (178.509±49.478) mg/L·h, respectively, while the C_max of each sample was (2.743±1.217), (7.109±2.603), (12.438±3.197), (15.727±4.68) and (20.044±5.736) mg/L, respectively. Compared to the Tartary buckwheat extract, the AUC_0-t and C_max of hydrolyzate samples 1, 2, 3 and 4 was significantly increased (p<0.05). Conclusions:With part of rutin converted to quercetin after acid hydrolysis, their cumulative absorption in rats was improved correspondingly.