ANTIMICROBIAL POTENTIALS OF LEAF EXTRACTS OF TRIDAX PROCUMBENS AND TOXICITY ON MAMMALIAN CELLS

Abstract

Tridax procumbens leaves were extracted to obtain hexane, ethyl acetate, methanol and aqueous extracts. An in vitro antimicrobial assay was conducted against Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella Typhi, Shigella flexneri, Klebsiella pneumoniae and Candida albicans. The safety of the extract was assessed by acute and sub-chronic toxicity tests to determine the toxic dose and to examine the impact of its long term administration. The aqueous extract inhibited the growth of S. Typhi and S. aureus with minimum inhibitory concentration (MIC) of 5 mg/mL and minimum bactericidal concentration (MBC) value of 10 mg/mL. The hexane extract inhibited the growth of S. Typhi, S. aureus, and C. albicans at 10 mg/mL with MIC of 5 mg/mL and an MBC value of 10 mg/mL. Acute toxicity studies showed an LD50 value that was greater than 5000 mg/kgbw. Sub-chronic studies revealed significant alterations in the haematological indices of animals exposed to 3000 mg/kgbw extract concentration. These results indicated that the oral administration of T. procumbens leaves is non-toxic at low doses and safe for use as a therapeutic for managing clinical conditions associated with Salmonella Typhi and Staphylococcus aureus. However, long-term administration at elevated doses may have adverse effect on renal and hepatic tissues.