Simultaneous determination of multiple bioactive components of Bu-zhong-yi-qi-tang in rat tissues by LC-MS/MS: Application to a tissue distribution study.

A liquid chromatography coupled with electrospray ionization mass spectrometry method was developed and validated for simultaneous determination of seven bioactive constituents including astragaloside IV, calycosin, glycyrrhizic acid, enoxolone, saikosaponin D, ferulic acid and hesperiden in rats' various tissues using diclofenac as the internal standard (IS). Biological samples were pretreated by protein precipitation with acetonitrile. The chromatographic separation was carried out on a C18 column with a gradient mobile phase consisting of acetonitrile and water (containing 0.1% formic acid and 4mM ammonium acetate). All analytes and IS were quantitated through electrospray ionization in negative ion multiple reaction monitoring mode. The mass transitions were as follows: m/z 829.7→783.3 for astragaloside IV, m/z 283.3→267.7 for calycosin, m/z 821.6→350.0 for glycyrrhizic acid, m/z 469.9→425.2 for enoxolone, m/z 825.7→779.6 for saikosaponin D, m/z 192.5→133.9 for ferulic acid, m/z 609.1→301.0 for hesperiden and m/z 293.6→249.9 for the IS, respectively. The lower limits of quantification for the seven analytes in different rat tissues were 0.2-20ng/mL. Bu-zhong-yi-qi-tang (Hochuekkito in Japan, Bojungikki-tang in Korea) is one of the most frequently prescribed traditional herbal formulas used in Korea, Japan, and China to treat gastrointestinal diseases, cancer and chronic fatigue syndrome. The validated method was successfully applied to a tissue distribution study of the seven components in rat tissue after oral administration of Bu-zhong-yi-qi-tang concentrated granule. The results of the tissue distribution study showed that the high concentration of seven components were mainly in the gastrointestinal tract.

Metabolic Interaction of the Active Constituents of Coptis chinensis in Human Liver Microsomes.

Coptis chinensis is commonly used in traditional Chinese medicine. The study investigated metabolic interaction of the active constituents (berberine, coptisine, palmatine, and jatrorrhizine) of Coptis chinensis in human liver microsomes. After incubation of the four constituents of Coptis chinensis in HLMs, the metabolism of the four constituents was observed by HPLC. The in vitro inhibition experiment between the active constituents was conducted, and IC50 value was estimated. Coptisine exhibited inhibitions against the formation of the two metabolites of berberine with IC50 values of 6.5 and 8.3 µM, respectively. Palmatine and jatrorrhizine showed the weaker inhibitory effect on the formation of the metabolites of berberine. Berberine showed a weak inhibitory effect on the production of coptisine metabolite with an IC50 value of 115 µM, and palmatine and jatrorrhizine had little inhibitory effect on the formation of coptisine metabolite. Berberine, coptisine, and jatrorrhizine showed no inhibitory effect on the generation of palmatine metabolite (IC50 > 200 µM). The findings suggested that there are different degrees of metabolic interaction between the four components. Coptisine showed the strongest inhibition toward berberine metabolism.

Effects of danshen ethanol extract on the pharmacokinetics of fexofenadine in healthy volunteers.

This study investigated the effect of multidose administration of danshen ethanol extract on fexofenadine pharmacokinetics in healthy volunteers. A sequential, open-label, two-period pharmacokinetic interaction design was used. 12 healthy male volunteers received a single oral dose of fexofenadine (60 mg) followed by danshen ethanol extract (1 g orally, three times a day) for 10 days, after which they received 1 g of the danshen extract with fexofenadine (60 mg) on the last day. The plasma concentrations of fexofenadine was measured by LC-MS/MS. After 10 days of the danshen extract administration, the mean AUC and C max⁡ of the fexofenadine was decreased by 37.2% and 27.4% compared with the control, respectively. The mean clearance of fexofenadine was increased by 104.9%. The in vitro study showed that tanshinone IIA and cryptotanshinone could induce MDR1 mRNA. This study showed that multidose administration of danshen ethanol extract could increase oral clearance of fexofenadine. The increased oral clearance of fexofenadine is attributable to induction of intestinal P-glycoprotein.