The influence of glycyrrhiza and antibiotics on the purgative action of sennoside a from Daiokanzoto in mice.

Daiokanzoto (DKT), a Kampo medicine that includes the combination of two crude drugs (rhubarb and glycyrrhiza), is clinically effective for constipation. The aim of this study is to clarify the influence of glycyrrhiza, three glycyrrhiza constituents (glycyrrhizin, liquiritin, and liquiritin apioside), and eight antibiotics on the purgative action of DKT, rhubarb, or sennoside A, a constituent of rhubarb, in mice. The purgative actions of rhubarb and sennoside A were significantly intensified when glycyrrhiza was co-administered orally to mice. Liquiritin and liquiritin apioside but not glycyrrhizin showed significant amplification of the purgative action in a dose-dependent manner. The purgative actions of DKT and sennoside A were significantly reduced by the pre-administration of ampicillin, cefcapene pivoxil, faropenem, fosfomycin, or kanamycin, but were not affected by the pre-administration of clarithromycin or levofloxacin. On the other hand, the purgative action of sennoside A was significantly reduced by the pre-administration of minocycline, whereas that of DKT was not affected. The effect of minocycline on the purgative action of sennoside A was lost when glycyrrhiza was co-administered. These results suggest that liquiritin and liquiritin apioside contribute as active substances for the purgative action of DKT, and some antibiotics reduce the purgative action of DKT and sennoside A. Furthermore, glycyrrhiza has the ability to recover the purgative action of sennoside A suppressed by minocycline via an unknown mechanism.