There is good evidence that anthrones/anthraquinones, known as active metabolites of emodin-type O- and C-glycosyl compounds which are found in many plant laxatives, influence the ion transport across colon cells, although the target transport systems have not yet been elucidated. There are various contradictory results used to explain the laxative action of these drugs. To elucidate this problem we tested 25 different anthrone/anthraquinone metabolites of plant drugs for their influence on different ion transport systems in Ehrlich cells as a model system. Comparing the laxative potency of these substances with their influence on the different ion transport systems involved in transepithelial ion transport makes it possible to exclude some transport processes as primary targets of the drugs. The following results were found: (1) Na+-K+-ZCl- cotransport was not inhibited by any of the substances tested. (2) Na+/K+-ATPase (pump) was inhibited by those 1,8-dihydroxyanthrones/anthraquinones that bear an additional phenolic hydroxyl group. This inhibition is indirect by interference with oxidative ATP production. However, there is no correlation to laxative action. (3) Cation channels were not influenced by these drugs. (4) Cl- -channels were inhibited significantly by those drugs that also show a laxative action. It is not clear, whether this effect is due to a direct interference with the channels or indirectly due to influences on the signal cascade triggering the transport. These results make it very likely that inhibition of Cl--channels is the primary action responsible for the laxative effect. Interference with oxidative ATP production as an additional effect may explain the known synergistic action described for the :combination of different anthrones/anthraquinones or anthranoid drugs, respectively.
herbal drugs, organic sources, laxatives
Publication DOI: 10.1021/bk-1998-0691.ch009Journal NLM ID: 100961485Publisher: American Chemical Society
Institutions: Department of Pharmacy, Pharmaceutical Biology, University of Leipzig, Leipzig, Germany
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