Alam_2016_Pharm.Biol__1

CONTEXT: Gaultheria trichophylla Royle (Ericaceae) and related species have been used in the traditional system of medicine for the treatment of diarrhoea, pain and inflammation. OBJECTIVE: The present investigation explores G. trichophylla for its potential activity in hyperactive gut disorders. MATERIALS AND
METHODS: Antidiarrheal activity was evaluated on castor oil induced diarrhoea in mice with reference to standard drug verapamil. Gut modulatory activity was performed on isolated jejunum tissue preparations on spontaneous and high potassium induced contractions. Butyrylcholinesterase (BChE) inhibitory activity was performed with an in vitro study. Extract was tested for toxicity in mice.
RESULTS: In the in vivo studies, the methanol extract of G. trichophylla and verapamil significantly (p < 0.05, 0.01, 0.001) inhibited the frequency of defecation as well as wetting of faeces when compared with the negative control. The methanol (Gt. MeOH) extract of G. trichophylla caused a dose-dependent inhibitory effect on spontaneous contractions in isolated rabbit jejunum preparations and exhibited a partial inhibitory effect against high K+ (80 mM) induced precontractions. Gt. MeOH shifted the Ca2+ concentration-response curves (CRCs) to the right, suggesting calcium channel blocking like constituents. In an in vitro assay Gt. MeOH inhibited BChE enzyme with an IC50 values of 35.52 +/- 1.17 mug/mL. The extract showed no toxicity in mice at the dose of 3 g/kg. DISCUSSION AND CONCLUSION: This study provides evidence that G. trichophylla possesses combinations of inhibitory and stimulatory effects mediated through possible cholinergic and less potent calcium blocking constituents, respectively. The latter may be responsible for the antidiarrheal effect.