Gastrointestinal stimulatory and uterotonic activities of dietary radish leaves extract are mediated through multiple pathways.

Raphanus sativus, commonly known as radish, is a food plant known worldwide for its culinary and medicinal properties especially as a laxative and abortifacient. This study reports the gastrointestinal and uterine tone modulatory activities of the crude extract (Rl.Cr) of radish leaves. Rl.Cr, showing the presence of saponins and alkaloids, exhibited a spasmogenic effect (0.03-10 mg/mL) in isolated rabbit jejunum, rat stomach fundus and uterus which was partially blocked by atropine. In contrast, Rl.Cr was found to be devoid of any stimulatory effect in rat ileum, instead showed an inhibitory effect (0.1 mg/mL) on the ACh dose-response curves. A mild relaxant effect was also observed in rabbit jejunum at the lower doses (0.1-0.3 mg/mL) but not against K(+)-induced contractions, ruling out a calcium channel blocking effect. In guinea-pig ileum, Rl.Cr exhibited a stimulant effect resistant to atropine while sensitive to pyrilamine pretreatment. The aqueous fraction, showing a strong presence of saponins, was found to be more efficacious than the non-polar fractions in its spasmogenic effect. This study shows the presence of species-dependent gastrointestinal effects of radish mediated partially through cholinergic receptors in rabbit and rat tissues, but through histaminergic activation in the guinea-pig, providing a scientific basis for its use in gut and uterine affections while also giving a wider picture of the activity profile of radish by using different species of animals. Copyright 2005 John Wiley & Sons, Ltd.