African Journal of Biotechnology Vol. 6 (24), pp. 2752-2757, 17 December 2007   

ISSN 1684–5315 © 2007 Academic Journals        

Full Length Research Paper

Preliminary antidiarrhoeal activity of methanolic extracts of Securinega virosa (Euphorbiaceae)

Magaji, M. G.^1*, Yaro, A. H.², Mohammed, A.³, Zezi, A. U.¹, Tanko, Y.³ and Bala, T. Y.³

¹Department of Pharmacology and Clinical Pharmacy, Faculty of Pharmaceutical Sciences, Ahmadu Bello University, Zaria, Nigeria.

²Dpartment of Pharmacology, Faculty of Medicine, Bayero University, Kano, Nigeria.

³Department of Physiology, Faculty of Medicine, Ahmadu Bello University, Zaria, Nigeria.

*Corresponding author. E-mail: magmas1@yahoo.com. Tel: 234-8034685849.

Accepted 8 November, 2007

Securinega virosa is used as remedy for diarrhoea in tropical Africa, but has not been investigated for its antidiarrhoeal activity. This study was therefore aimed at investigating the methanolic extracts of the leaves, stem bark and root bark for antidirrhoeal activity, using castor oil-induced diarrhoeal model in mice. The effects of these extracts on perfused isolated rabbit jejunum were also evaluated. The methanolic leaves extract (8 x 10^-5 – 1.6 x 10^-3 mg·ml-1) produced a dose-dependent relaxation of the rabbit jejunum, while the methanolic stem bark and root bark extracts (2 x 10^-5 – 3.2 x 10^-3 mg·ml-1) produced contraction of the tissue. The methanolic root bark extract produced a dose-dependent protection against the castor oil- induced diarrhoea with the highest protection (100%), obtained at 100 mg·kg-1 comparable to that of loperamide (5 mg·kg-1), the standard agent. The leaves extract also protected the mice but was not dose-dependent. The highest protection (60%) was obtained at the lowest dose (50 mg·kg-1). The stem bark extract did not protect the animal against diarrhoea. The preliminary phytochemical analysis revealed that the three extracts contained similar phytochemical constituents which include alkaloids, tannins, saponins, flavonoids and cardiac glycosides. However, only the leaves extract contained anthraquinone glycosides. The acute toxicity test revealed the median lethal dose (LD₅₀) values for the leaves, stem bark and root bark extracts to be 1265, 288.5 and 774.6 mg·kg-1 respectively. This suggests that the stem bark extract is relatively the most toxic. These results obtained revealed that the leaves and root bark extracts possess pharmacological activity against diarrhoea and may possibly explain the use of the plant in traditional medicine.

Key words: Securinega virosa, antidiarrhoeal, castor oil, isolated tissue, methanolic extracts.