Evaluation of the Methanol Whole Root Extract of Securidaca longipedunculata for Antitrypanosomal Activity in vitro and in vivo

Abstract

Objectives: to evaluate the antitrypanosomal effect of the methanol whole root extract of Securidaca longipedunculata in vitro and in vivo. Methods: acute toxicity effect of the methanol extract of S longipedunculata whole root was investigated using oral and intraperitoneal (IP) dosages. In vitro trypanocidal activity was evaluated at the extract concentration range of 78 – 1 µg/ml. Trypanocidal activity was evaluated at 10 minutes interval for 1 h and partial or total elimination of trypanosomal motility indicates degree of trypanocidal activity. For in vivo effects, the extract was evaluated at the doses of 200, 300

and 400 mg/kg per os for 9 days. Effect on hematology, liver enzyme markers and weight gain were also investigated. Results: the extract was well tolerated per os up to 5000 mg/kg, but was very toxic IP with LD50 of 3.3 mg/kg. The extract showed excellent in vitro trypanocidal activity with a minimum inhibitory concentration of 5µg/ml 20 minutes post-incubation. An MIC of 2.1µg/ml 20 minutes post-incubation was established for diminazene diaceturate. Significant (p<0.05) in vivo antitrypanosomal effect was observed at the dose of 400 mg/kg 6 days post-treatment and in all the extract treated groups 9 days post-treatment. There was also significant (p<0.05) improvement of the packed cell volume (PCV) and weight in all extract treated groups. Liver enzyme markers like Serum alanine aminotransferase (ALT) and serum aspartate aminotransferase AST were also significantly decreased at the extract dose of 400 mg/kg. Conclusion: the methanol extract of S longipedunculata showed promising antitrypanosomal activity both in vitro and in vivo, thereby justifying its traditional use in Northern Nigeria in the treatment of sleeping sickness.