STUDIES ON PHARMACOLOGICAL BASIS FOR THE USE OF PSYLLIUM HUSK (ISPHAGHUL) IN CONSTIPATION AND DIARRHOEA

ABSTRACT

Background: Plantago ovata (Ispaghul) is traditionally used for the management of chronic constipation and diarrhea.

Aims: The study was aimed to provide the pharmacological basis for the medicinal use of Ispaghul in constipation and diarrhea.

Methods and Settings: The crude extracts of two varieties (Indian and Pakistani) of Ispaghul were investigated for gut stimulant and relaxant effects using isolated tissue experiments. Isolated tissue preparations, such as guinea-pig ileum and rabbit jejunum were used for studying the possible mode of action. The stimulatory and relaxant effects were measured using isotonic transducers coupled with student oscillograph/Power Lab data acquisition system integrated with a computer. The in-vivo experiments were conducted in mice for the assessment of laxative, antisecretory and antidiarrheal activities. Both the in-vivo and in-vitro studies were carried out at Aga Khan University, Karachi. 

Results: The crude extract of Indian [Po.Cr (Ind)] and Pakistani [Po.Cr (Pak)] varieties of Ispaghul exhibited dose-dependent stimulant effect (0.1 -10 mg/ml) in isolated rabbit jejunum and guinea-pig ileum. The spasmogenic effect was partially blocked by atropine (0.1 µM) and SB-203186 (1 µM), a 5-HT₄ receptor antagonist. When tested on high K⁺ (80 mM)-induced contractions, Po.Cr (Ind) caused a partial relaxation, while complete relaxation was achieved by Po. Cr. (Pak). These effects were potentiated in the tissue pretreated with atropine, indicating Ca⁺⁺ channel blocking like activity along with partially cholinergic and 5-HT₄ receptor-mediated gut stimulant effects. The channel blocking like activity was further confirmed when; both crude extract shifted the calcium concentration-response curves to the right similar to verapamil. Activity-directed fractionation of the crude extract revealed the distribution of spasmogenic and spasmolytic effects both in aqueous and organic fractions. Ispaghul exhibited dose-dependent antidiarrheal (100 and 1000 mg kg/kg), laxative (100 and 300 mg kg/kg) and antisecretory (500 and 1000 mg kg/kg) activities in mice.

Conclusion: The gut modulating effect of Ispaghul is dose dependent and mediated through multiple pathways, thus explaining its use in gut disorders.