Pharmacological basis for the medicinal use of Holarrhena antidysenterica in gut motility disorders.

BACKGROUND

Holarrhena antidysenterica Wall. (Apocynaceae) is widely used in traditional medical system for treatment of constipation, colic, and diarrhea.

OBJECTIVE

This study was carried out to provide pharmacological basis for medicinal use of Holarrhena antidysenterica in gastrointestinal disorders.

METHODS

Hydro-ethanolic crude extract of Holarrhena antidysenterica (HaCE) and its fractions were studied in various gastrointestinal isolated tissue preparations.

RESULTS

In guinea pig ileum tissues, HaCE at 0.3-10 mg/mL caused pyrilamine-sensitive spasmogenic effect. When tested in spontaneously contracting rabbit jejunum preparations, HaCE (0.01-3.0 mg/mL) caused moderate stimulation, followed by a relaxant effect at next higher concentrations. In presence of pyrilamine, the contractile effect was blocked and the relaxation was observed at lower concentrations (0.01-0.3 mg/mL). HaCE inhibited the high K(+) (80 mM)-induced contractions at concentration range of 0.01-1.0 mg/mL and shifted Ca(++) concentration response curves to the right, like that caused by verapamil. Activity-directed fractionation revealed that the spasmogenic component was concentrated in the aqueous fraction, while the spasmolytic component was concentrated in the organic fraction.

CONCLUSIONS

These results indicate that the gut stimulant and relaxant activities of Holarrhena antidysenterica are mediated possibly through activation of histamine receptors and Ca(++) channel blockade, respectively and this study provides sound mechanistic background for its usefulness in gut motility disorders such as constipation, colic, and possibly diarrhea.