Instability of rhein-9-anthrone as a problem in pharmacological and analytical use.
The stability of rhein-9-anthrone, one of the main and most active metabolites of the sennosides A + B, was studied under physiological conditions. A high-pressure liquid chromatographic method for the determination of rhein-9-anthrone and its oxidation products, rhein and sennidins A + B, was developed. Rhein-9-anthrone, dissolved in Tyrode buffer at pH 6.5 or 7.5 at a concentration of 10(-4) mol/l, completely disappeared from a solution warmed to 37 degrees C within 30 min. More than 90% were transformed into rhein and sennidins A + B. Pharmacological experiments in rats showed that net water absorption in the small intestine was reversed to net secretion by rhein-9-anthrone, whereas rhein and sennidins in corresponding concentrations were ineffective. As at least rhein is known to stimulate secretion under different experimental conditions, all pharmacological results with rhein-9-anthrone must be interpreted with caution and should be checked whether they essentially differ from those of its main oxidation products.
Grimminger
W
W
Department of Chemistry, Dr. Madaus GmbH & Co., Cologne, FRG.
Leng-Peschlow
E
E
D000818:Animals; D000873:Anthracenes / Q000032:analysis / Q000494:pharmacology*; D002855:Chromatography, Thin Layer; D004355:Drug Stability; D005260:Female; D007408:Intestinal Absorption / Q000187:drug effects; D007421:Intestine, Small / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D014867:Water / Q000378:metabolism; D000095322:Anthrones
D000873:Anthracenes; D014867:Water; C055876:rhein-9-anthrone; D000095322:Anthrones; C013946:dihydroxydianthrone