Phytochemical and comparative antibacterial studies on the crude ethanol and aqueous extracts of the leaves of Lecaniodiscus cupanoides Planch (Sapindaceae).

Phytochemical investigation was carried out on the leaves of Lecaniodiscus cupanoides Planch (Sapindaceae). The diameter of the zones of inhibition of the 90% ethanol and aqueous extracts of the leaves were compared in order to determine the relative activity of the extracts against the tested microorganisms and also to verify its claimed ethnomedicinal use in the treatment of microbial infections. Phytochemical tests were carried out employing standard procedures. The antimicrobial activity of the extract was tested against standard strains and clinical isolates of some aerobic bacteria using the agar well diffusion method. Commercial antibiotics were used as positive reference standards to determine the sensitivity of the strains. The minimum inhibitory concentration (MIC) values were also determined using the agar well diffusion method. Preliminary phytochemical studies revealed the presence of flavonoids, tannins, saponins and cardiac glycosides as the chemical classes of compounds present in the crude extract. The extracts showed inhibitory activity against clinical isolates of Bacillus subtilis. Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa Staphylococcus aureus and a standard strain of Staphylococcus aureus (NCTC 10788). The ethanol extract was more active than the aqueous extract against all the microorganisms tested, except against the clinical isolates of Staphylococcus aureus. The MIC values ranged from 2.5 to 6.25 mg/mL for all the organisms tested. The results showed that the ethanol extract was more potent than the aqueous extract. The broad spectrum of activity displayed by the extracts would appear to provide the scientific basis for the use of the leaves of Lecaniodicus cupanoides for dressing of boils, burns and cuts in ethnomedicine.