The Metabolism And Tissue Residue Studies Of Main Alkaloids From Macleaya Cordata In Rat And Pig

Sangrovit has been widely used as feed additive of Chinese veterinary medicine in livestock breeding.The main active components of Sangrovit are sanguinarine(SA),chelerythrine(CHE).And allocryptopine(ALL)and protopine(PRO)are also the main active comonents of Macleaya cordata.Pharmacokinetic studies showed that their bioavailability is very low,most of them were excreted from the gastrointestinal tract.At present,the metabolism of SA had been studied deeply and systematically in our laboratory,but there are few studies on the metabolism and tissue residue of CHE,ALL,PRO at home and abroad.Objective: The aims of this study were:(a)to explore the metabolism in vivo and vitro of CHE,ALL,PRO in rat and pig and species differences of those,(b)to summarize the characteristics of their metabolism and residue distribution,(c)to determine the metabolic enzymes involved in the reduction of CHE,(d)to provide the basis for interpreting pharmacokinetics of three kinds of alkaloids and their food safety evaluation.Methods: The isolation and identification of CHE,ALL,PRO metabolites were performed using high-performance liquid chromatography/quadrupole-time-of-flight mass spectrometry(HPLC/Qq-TOFMS)in vivo and in vitro;A HPLC-QQQ method was used to quantitatively analyze the residual distribution of CHE,ALL,PRO in rats;A HPLC method was used to detect the effects of 4 specific inhibitors on DHCHE formation in liver microsomes and cytosol.Results: A total nine CHE metabolites,eight ALL metabolites and five PRO metabolites were identified in liver S9 in vitro.Among of this,one CHE metabolites,seven ALL metabolites and two PRO metabolites were identified for the first time.The metabolic rates of the three alkaloids in the rat liver S9 were higher than those in pigs.And a total eight CHE metabolites,ten ALL metabolites and ten PRO metabolites were identified in rat in vivo.Among of this,five ALL metabolites and six PRO metabolites were identified for the first time.No phase II metabolite of CHE was found,but two glucuronidated ALL and six glucuronidated PRO metabolites were detected in vivo in rat.The results showed that the higher residue of CHE in the spleen at 24 h and liver at 48 h were 44.04 ng/g and 20.64 ng/g,respectively.And the residue of CHE in the heart,lung and kidney were less than 4 ng/g.The residue of ALL in cecal contents and tissues all were less than 3 ng/g.The highest residue of PRO was 61.8 ng/g in the liver at 48 h after administration and the residue of others tissues were less than 6.5 ng/g.The incubation inhibition result showed that the metabolic enzymes involved in CHE reduction in rat liver microsome were cytochrome P450 reductase and xanthine oxidase;The metabolic enzymes involved in CHE reduction in rat liver cytosol were carbonyl reductase,xanthine oxidase,quinone oxidoreductase 1 and quinone oxidoreductase 2;The metabolic enzyme involved in CHE reduction in pig liver microsome may be cytochrome P450 reductase;And the metabolic enzymes involved in CHE reduction in pig liver cytosol are not clear.Conclusion: The species differences exist in vitro metabolism of CHE,ALL,PRO in rat and pig.The metabolic rates of the three alkaloids in the rat liver S9 were higher than those in pig.Most of the CHE,ALL metabolites were mainly detected in rat feces,and most of the PRO metabolites were detected in the urine.The low residue of three alkaloids existed in the most tissues of rat after administration.These results not only provide a theoretical basis for interpretated the pharmacokinetics of CHE,ALL,PRO,but also provide a scientific basis for their food safety evaluation.