ANTI-DIARRHOEAL AND ANTISPASMODIC EFFECTS OF LEAF EXTRACT OF PTEROCARPUS SANTALINOIDES

Diarrhoea is one of the popular gastrointestinal disorders with high mortality especially in children. Certain medicinal plants are being used in traditional medicine practice to treat and control diarrhoea. One of such plants is the leaves of Pterocarpus santalinoides. The need to scientifically ascertain this folkloric claim and the possible identification of the active constituents therein motivated this study. The methanol leaf extract of P. santalinoides was prepared and screened for activity using castor-oil induced diarrhoea, gastrointestinal motility tests (charcoal transit test) and inhibition of contraction induced by histamine (H) and acetylcholine (Ach) on isolated rabbit jejunum. The results indicated that the extract at 200 mg/kg dose exhibited a significant inhibition (P < 0.05) of castor-oil induced diarrhoea when compared with a standard antidiarrhoeal agent, diphenoxylate hydrochloride (5 mg/kg). The extract also at 200 mg/kg dose level showed a significant inhibition (P<0.05) on gastrointestinal motility when compared with the vehicle (3 % Tween 80). The extract also exhibited a dose dependent inhibition on the contraction induced by acetylcholine and histamine on rabbit jejunum as well as the abolition of spontaneous pendular movements of the smooth muscles of the rabbit jejunum. The acute toxicity study exhibited an LD50 greater than 5000 mg/kg. The phytochemical screening revealed the presence of carbohydrates, resins, terpenoids, steroids, saponins. The extract exhibited both antidiarrhoeal and antispasmodic effects which could be through inhibition of histaminergic and cholinergic mechanisms via their respective receptors abundant in the GIT. The antidiarrhoeal effect of this plant can be explored for therapeutic advantages as an alternative for treatment of diarrhoea and further research is expected to confirm the active phytochemical constituent(s) responsible for the activity. Keywords: P. santalinoides, antidiarrhoeal, antispasmodic and rabbit jejunumNigerian Journal of Pharmaceutical Research, Vol. 8 No 1 pp. 138 - 144 (September 2010