The effect of different storage conditions on the chemical stability, laxative effect and acute toxicity of sennoside solutions.

This paper investigates the effect of different storage conditions on the chemical stability, laxative effect and acute toxicity of sennoside solutions. The variables in storage conditions were pH, time and temperature (room temperature or 100 degrees). The chemical stability of sennosides in aqueous solutions was found to be pH-dependent, with the best stability at pH 6.5 (t90. = 8.4 months) and the poorest at pH 8.0 (t90. = 2.5 months). Two years of storage at room temperature did not reduce the laxative potency in mice, regardless of the pH. After 4.25 years of storage the potency declined in alkaline solutions only. The degradation products with laxative potencies are chemically unknown. The acute toxicity of sennoside solutions increased with time during storage, the acid solution being more toxic than either the neutral or alkaline ones.