Effects of Cassia alata Root Extract on Smooth Muscle Activity

Ethno Pharmacological Relevance: The root of Cassia alata had been preferentially used early this century in the south-south Nigeria, especially in Old Calabar province as an abortifacient by women, for the termination of early pregnancy with apparent success. Some studies and investigations have been carried out on the seeds, leaves, barks and pods of Cassia species and in particular, the seeds, leaves and barks of Cassia alata have been studied to a greater extent but a few study had been reported on the pharmacological and toxicology properties of Cassia alata. roots.
Aims of the Study: This study investigated the acute toxicity effect (i.p. LD50) of ethanolic Cassia alata (RCAE) root extract in albino mice only; also the ethanolic and aqueous roots extracts on smooth muscle activity in rat and rabbit. It also proffer into the possible mechanism of its action by comparism to known standard agonists and antagonists.
Materials and Methods: The acute toxicity effect (i.p. LD50) of Cassia alata roots was investigated using forty two (42) Albino mice of both sexes (23-31 g). The mortality in each group was assessed twenty four (24) hours each day, and for three (3) consecutive days adding up to 72 hours after administration of the roots extract. In the second experiment, the rat and rabbit were assessed for the uterine smooth muscle activities using the extract and comparism standard agonists and antagonists.
Results: The LD50 of the treated mice intraperitoneally was 263±25 mg/kg. The influence of the ethanolic Cassia alata root extract (RCAE) on rat and rabbit smooth muscle preparations exhibited marked dose-dependent spasmodic effect on drug-induced contractions of the gastrointestinal tracts (GIT) and uterus/fallopian smooth muscle preparations tested. The log dose-response curves of Aceteylcholine and Histamine were shifted to the right in the presence of RCAE (8 x10-4 g/ml) with increasing Kd50 (EC50) values, but with decreasing amplitude (P<0.01). The stimulatory effect of the ethanolic and aqueous extract of Cassia alata root (8 x10-4 g/ml) on the rabbit and rat GIT and uterus/fallopian tube smooth muscle was not attenuated by atropine (4.8 x10-6 g/ml), propranolol (1.5 x10-3 g/ml) or phentolamine (1 x10-4 g/ml). But preadministration of Aminophylline (5 x10-3 g/ml) significantly attenuated the contraction of RCAE (8 x10-4 g/ml) induced spasms on the rat uterus (P<0.05-0.01). RCAE also exhibited significant spasmodic effect on the smooth muscle in response to increased Ca2+ concentration in a high Ca2+ free media. The microscopic examination of the histopathologic effect of RCAE revealed mild to moderate chronic inflammatory reaction on the uterine mucosa.
Conclusion: Our findings in this study indicate that, the ethanolic extract of the root of Cassia alata is moderately toxic with a lethality dose (LD50) of 263±25 mg/kg and that Cassia alata root may contain pharmacologically active ingredients, which exhibits significant pharmacological contractility effects. Cassia alata roots extracts may be pharmacologically more potent than the leaf extract especially on the reproductive tract. Cassia alata root may also be a possible plant source of abortifacient and laxative drugs.