Effect of extract and fractions of stem bark of Morinda lucida Benth (Rubicaceae) on castor-oil induced diarrhea in mice

Abstract

Morinda lucida Benth is a common Nigerian medicinal plant generally used to cure
malaria parasite infection, though there is a lack of scientific reports on its capacity to
treat diarrhea. The current study evaluated the effect of extract and fractions of stem
bark of Morinda lucida Benth (Rubicaceae) on castor-oil-induced diarrhea in mice. The
ground (500 g) was macerated in 2500 mL of methanol for 72 h, thereafter filtered and
concentrated to obtain methanol extract. The extract (10 g) was subjected to gradient
elution to afford different fractions. The phytochemical screening method was used to
investigate the constituents of extract and fractions. The method of Lorke’s was
employed in the acute toxicity study. The evaluation of anti-diarrhea activity was carried
out by the castor-Oil-induced gastro-intestinal motility model. The secondary
metabolites present in the extract and fractions were alkaloids, flavonoids, saponins,
tannins, terpenoids, cardiac glycoside, anthraquinone glycoside, and steroids. The
Acute toxicity indicated no mortality or any adverse behavioral change even at 5000
mg/kg body weight. The extract at 200 mg/kg dose gave better antidiarrheal activity
than the 400 mg/kg dose indicating that the effect is not dose dependent. Among the
fractions ethyl acetate at 400 mg/kg showed better activity and indicated no significant
difference when compared to loperamide at 2 mg/kg dose. When compared, the
antidiarrheal activity of the extract and fractions differed significantly at (p<0.05) with
negative control. Morinda lucida's stem bark has an outstanding antidiarrheal effect as
a result of its copious bioactive constituents.