Effect of Berberine on Pharmacokinetics of Baicalin in Rats

AIM:To investigate the mechanism of effects of beberine to pharmacokinetics of baicalin in rats.METHODS:Three groups of rats received oral administration of baicalin alone,co-administration of baicalin and berberine and separate administration of berberine and baicalin,respectively.Blood samples were obtained in a designed time.Concentrations of baicalin in plasma were measured by HPLC and the corresponding pharmacokinetic parameters were estimated.The everted sac experiment was introduced to investigate the absorption mechanism of baicalin and fermentation of baicalin in feces suspension experiment was introduced to investigate whether berberine affected the degradation of baicalin.RESULTS:In vivo,the blood concentration and exposure of baicalin significantly decreased after oral co-administration of baicalin(200 mg·kg-1)and berberine(240 mg·kg-1)in rats as compared with single administration of baicalin(200 mg·kg-1).The situation was improved in separate administration of baicalin(200 mg·kg-1)and berberine(240 mg·kg-1).In vitro,the transport of baicalin showed a regional variation in rat intestine and the transport rate of baicalin was ileum duodenum jejunum.Baicalin was degraded when incubated in feces suspensions of rats.The degradation of baicalin in feces suspensions of rats previously treated with berberine(240 mg·kg-1)was slower than that in the control.CONCLUSION:The experimental findings indicated that the co-precipitation between baicalin and berberine might decrease the exposure of baicalin,also berberine could decrease the systematic exposure of baicalin via inhibiting the hydrolization of baicalin.These interactions should be paid attention to in clinical studies when baicalin is administered in combination with berberine.