antidiarrheal action of hydroalcoholic extract of pycnocycla spinosa in comparison with loperamide and dicyclomine

pycnocycla spinosa decne. ex boiss. var. spinosa (fam. umbelliferae) is an essential oil-containing wild plant growing in central part of iran. hydroalcoholic extract of pycnocycla spinosa has antispasmodic and antidiarrheal activity. the aim of this study was to further investigate antidiarrheal and small intestinal transit effect of p. spinosa extract for a comparison with loperamide and dicyclomine. male mice fasted over night with free access to water, were treated with p. spinosa extract, loperamide, dicyclomine or vehicle (p.o.). after thirty min, castor oil was given orally to the animals. in separate groups, magnesium sulphate was given in the beginning and 30 min after the extract or drugs were administered. the onset and number of wet defecation on the absorbent paper was recorded for each animal for 2.5 h. in another group of mice, intestinal transit of charcoal meal after the administration of extract, loperamide or dicyclomine was determined and compared with the control group. p. spinosa extract sharply reduced castor oil and magnesium sulphate induced diarrhea. the extract, in dose of 1 mg/kg, had antidiarrheal effect similar to loperamide (2 mg/kg) and with dose of 0.5 mg/kg, its antidiarrheal action was greater than that of dicyclomine (5 mg/kg). unlike dicyclomine, p. spinosa extract significantly reduced the small intestinal transit of charcoal meal. however, its inhibitory effect on intestinal transit was less than loperamide. this study shows that anti-diarrhea l effect of p. spinosa extract is similar to loperamide. the inhibition of intestinal propulsion is a most likely mechanism that may account for anti-diarrhea l activity of the extract.