The antispasmodic effect of aqueous root bark extract of Carissa edulis (Forssk.) Vahl on isolated rabbit jejunum is mediated through blockade of calcium channels

Background: Spasms of the gut underlie hyperactive gut disorders. These conditions are highly prevalent and impart greater health care cost. Herbal antispasmodic remedies form a source of affordable, safe and easily available treatments in low resource areas. There is, therefore, a need to scientifically evaluate the therapeutic potential of these remedies. This study investigated the antispasmodic effect of aqueous root bark extract of Carissa edulis, herb used to manage hyperactive gut disorders such as abdominal colic and diarrhea. Materials and methods: Pieces of jejunum were isolated from adult New Zealand White rabbits. They were mounted in an organ bath containing Tyrode's solution. The rate and force of contraction were recorded using Powerlab coupled to Chart5 Software. The effects of the extract (0.1-10.0 mg/ml) on spontaneous jejunal contraction were investigated. The effect of 1.0 and 3.0 mg/ml extract was investigated on acetylcholine, KCl and CaCl2 induced contraction. Results: Carissa edulis extract dose-dependently (0.1-10 mg/ml) significantly decreased the force but not the rate of spontaneous jejunal contraction. Extract (1 and 3 mg/) significantly decreased the magnitude of acetylcholine, KCl and CaCl2 induced contraction. Conclusions: Aqueous root bark extracts of Carissa edulis possess a significant antispasmodic effect on rabbit jejunum. This appears to be through calcium channel blockade. These results validate its use as a remedy for hyperactive gut disorders.