Gut modulator effects of Conyza bonariensis explain its traditional use in constipation and diarrhea

BACKGROUND AND OBJECTIVES: The current investigation was carried out to explore the pharmacological basis of the crude extract of Conyza bonariensis (Cb.Cr) for its use in constipation and diarrhea. MATERIALS AND METHODS: The plant extract of Conyza bonariensis (C. bonariensis) was prepared, isolated guinea-pig ileum and rabbit jejunum preparations were used to evaluate its gut modulator effects. RESULTS: The Cb. Cr (0.3-10 mg/mL) exhibited spasmogenic effect in isolated guinea-pig ileum preparation, which was about 19-84% of the acetylcholine maximum. Pretreatment of the tissues with atropine (0.1 mu M) abolished the contractile effect, similar to acetylcholine. Among the fractions, only the butanol fraction exhibited atropine sensitive contractile effect. In isolated rabbit jejunum preparations, Cb. Cr produced appreciable atropine-sensitive spasmogenic effect at lower concentrations (0.03-0.3 mg/mL) followed by spasmolytic effect at next higher concentration (1.0 and 3.0 mg/mL). Cb. Cr caused an inhibition of the high K+ induced contraction in isolated rabbit jejunum preparation with EC50 value of 0.62 mg/mL. Similarly, verapamil, a standard calcium blocker, inhibited high K+ induced contraction in isolated rabbit jejunum preparations. Cb. Cr caused a right ward shift in the Ca++ concentration response curve, similar to verapamil. Among various fractions of C. bonariensis, only hexane and ethylacetate fractions showed spasmolytic effects. CONCLUSIONS: The crude extract of C. bonariensis contains spasmogenic and spasmolytic constituents, which explains its medicinal use in constipation and diarrhea.