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Laxative action of sennoside A, which causes decreased colonic aquaporin‐3 expression, is controlled by the anti‐inflammatory effect of glycyrrhizin
Author(s) -
Kon Risako,
Yamamura Miho,
Fujikawa Tetsuya,
Uemura Takefumi,
Kusunoki Yoshiki,
Ikarashi Nobutomo,
Sugiyama Kiyoshi
Publication year - 2018
Publication title -
traditional and kampo medicine
Language(s) - English
Resource type - Journals
ISSN - 2053-4515
DOI - 10.1002/tkm2.1090
Subject(s) - glycyrrhizin , laxative , medicine , pharmacology , glycyrrhiza , diarrhea , traditional medicine , adverse effect , constipation , alternative medicine , pathology
ABSTRACT Aim The laxative action of daiokanzoto (a compound containing rhubarb and glycyrrhiza) is thought to be due to sennoside A, an ingredient in rhubarb. Glycyrrhizin, which has anti‐inflammatory effects, is the main ingredient in glycyrrhiza, and it alleviates adverse reactions, such as abdominal pain and painful defecation, due to rhubarb. No consensus has been reached, however, on why daiokanzoto contains glycyrrhiza. We found that sennoside A exerts a laxative action by decreasing aquaporin‐3 (AQP3) expression through the activation of macrophages in the colon. This study analyzed the effect of glycyrrhizin on the laxative action of sennoside A focusing on AQP3 expression. Methods Sennoside A, glycyrrhizin, or a combination of both were given orally to rats, and diarrhea severity was assessed. The expression of AQP3, inflammatory cytokines, and cyclo‐oxygenase (COX) was analyzed. Results Although diarrhea occurred when sennoside A and glycyrrhizin were given together orally, it was less severe than when sennoside A was used alone, and, correspondingly, only sennoside A inhibited AQP3 expression to a greater extent than the combination of both drugs. When glycyrrhizin was given concomitantly, the sennoside A‐induced increased expression of pro‐inflammatory cytokines and COX‐2 was suppressed. Conclusions The laxative action of sennoside A and the decreased expression of AQP3 were suppressed when sennoside A and glycyrrhizin were given concomitantly, likely due to the anti‐inflammatory effects of glycyrrhizin. This indicates that glycyrrhizin both attenuates the adverse reactions caused by sennoside A and plays a role in its laxative action.