Effects of senna and its active compounds rhein and rhein-anthrone on PAF formation by rat colon

A single or a prolonged oral administration of senna (60 mg kg-1) to rats did not increase either colonic PAF (platelet activating factor) content or intraluminal release of acid phosphatase. A similar result was observed in the colonic tissue of rats perfused in-vitro with rhein (1-300 micrograms mL-1) or rhein-anthrone (1-300 micrograms mL-1). A single or prolonged administration of castor oil (2 mL) to rats increased both colonic PAF content and intraluminal release of acid phosphatase. Colonic tissue of rats perfused in-vitro with calcium ionophore A23187 (1 and 10 micrograms mL-1) formed large amounts of PAF and acid phosphatase. Since PAF can mediate intestinal damage and acid phosphatase is a marker of cellular injury, we conclude that senna and its derivatives, rhein and rhein-anthrone, are well tolerated in rats.