Antibacterial activities of aqueous and ethanolic extracts of Pistia stratiotes L.

Abstract

Aqueous and ethanolic extracts of Pistia L. (Water lattuce or duckweed) ‘kainuwa’ (in Hausa) were in vitro assayed for antibacterial activity. The extracts impregnated assayed for antibacterial activity against clinical isolates of Staphylococcus aureus, Salmonella typhi, Escherichia coli, Klebsiella sp. Proteus sp. and Pseudomonas
aeruginosa. After inocubation Staph. aureus, S. typhi and E. coli showed sensitivity to the aqueous extract at disc concentration range of 2.0-20mg/ml, 40-100mg/ml respectively. Both the two extracts however, showed no activity against Proteus sp., Klebsiella sp and Pseudomonas aeruginosa. The observed minimum inhibitory concentrations (MICs) of the aqueous extract for Staph. aureus, S. typhi and E. coli were respectively, 5.0, 60.0 and 100mg. The study demonstrates some agreement with earlier claims on the ethnomedicinal use of the plant in the treatment of ulcers, fevers, bacterial infection of the eye, ear, nose throat as well as the stomach and skin. More work is thus recommended especially on purification, spectrum of activity and the toxicology of the active constitute(s) of the plant.