Acute and sub-acute toxicity study of the root extracts of Fagaropsis hildebrandtii in mice and evaluation of their antimicrobial effects

Abstract

Background: Among the Kamba community of Kenya, roots ofFagaropsis hildebrandtii(FH) are boiled and used in managing cough, fertility problems, and microbial infections. The safety of this plant in oral administration and the validity of the ethnomedical claims are unverified. This study evaluated the toxicity of the aqueous and hexane root extracts of FH in mice and antimicrobial effects againstStaphylococcus aureus,Salmonella typhimuriumandCandida albicans.Methods: Doses (300 and 2000 mg/kg) of the extracts were administered orally to mice for 14 days. The weight, feed, and water consumption, organ weight of mice and gross macroscopy of the liver were used in evaluating acute toxicity. Mice were additionally treated with 250, 500, and 1000 mg/kg body-weight doses of the extracts for 28 days and haematological, biochemical, and histological parameters noted. The minimum inhibitory and minimum bactericidal/fungicidal concentrations (MIC; MBC/MFC) of the extracts against the aforementioned pathogens were determined by broth dilution.Results: Acute oral toxicity of the extracts was >2000 mg/kg, there were dose dependent changes in haematological and biochemical parameters, all female mice died when treated with doses of 1000mg/kg and doses ≥500 mg/kg caused tubular degeneration and haemorrhage of the kidney, cloudy swelling of hepatocytes, and multifocal necrosis and pyknosis in the liver. The MBC/MIC ratio of each of the extracts againstStaph. aureusandS. typhimuriumwas 2, whileC. albicanswas not sensitive to any of the extracts.Conclusions: Long term use of FH root extracts was associated with dose-dependent changes in the mice kidney, liver and in biochemical and haematological parameters. Root extracts of FH are bactericidal againstStaph. aureusandS. typhimuriumbut have no effect onC. albicans. Future work should aim at identifying the metabolites responsible for the observed toxic and bactericidal effects of the FH root extracts.