Laxative activities of Cassia sieberiana and Senna obtusifolia

The root and stem bark of Cassia sieberiana DC. (Caesalpiniaceae) and the root of Senna obtusifolia (Linn) Irwin and Barneby (Caesalpiniaceae), used for constipation in Nigeria, were assayed for laxative properties in male albino rats using the official senna leaf (Senna alexandrina Mill. family Caesalpiniaceae) as the reference standard. This is with a view to finding alternative laxative drug to official senna which is presently being imported into Nigeria from the United Kingdom.

The mean percentage of wet faeces in rats, an indication of laxative activity, were obtained using established methods. The laxative activity was established at 500 mg/kg after the infusion of the drug was orally administered on male albino rats following established methods while a set of data was analyzed at 95 % confidence level.

At 500 mg/kg, Senna obtusifolia root gave about 45 % wet faeces while Cassia sieberiana root gave about 40 % wet faeces while at the highest dose of 700 mg/kg, they produced 60 % and 38 % wet faeces, respectively. At these two doses, the official Senna gave 50.6 % and 66 % wet faeces, respectively. Thus, S. obtusifolia and C. sieberiana roots exhibited 89 % and 80 % of the potency of S. alexandrina (the official drug), respectively. The analysis of variance revealed a significant statistical difference in the levels of wet faeces produced by rats dosed with C. sieberiana root.

The results have shown that the roots of the two species could be developed as mild laxative drugs for children and pregnant women for whom the official senna will be contraindicated.