Antidiarrheal, antisecretory, and bronchodilatory activities of Hypericum perforatum

This study describes the antidiarrheal, antisecretory, and bronchodilatory activities of Hypericum perforatum Linn. (Hypericaceae), commonly known as St. John's wort, to justify its traditional use in the hyperactivity of the gastrointestinal and respiratory systems. The crude extract of Hypericum perforatum (Hp.Cr) at a dose of 500mg/kg caused 20% protection against castor oil-induced diarrhea in mice and 60% at 1000mg/kg (p<0.05 vs. saline). Hp.Cr at 300 and 1000mg/kg reduced the castor oil-induced fluid accumulation in mice to 107.0±3.3g (p<0.01) and 84.0±4.2g (p<0.001) respectively, whereas in the castor oil-treated group, it was 126.9±3.9g. When tested against carbachol (CCh)-mediated bronchoconstriction in rats under anesthesia, Hp.Cr dose-dependently (3-30mg/kg) suppressed the CCh (1μmol/kg)-induced increase in the inspiratory pressure. Thus this study rationalizes the Hypericum perforatum usefulness in overactive gut and airways disorders, such as diarrhea and asthma.