ANTIBACTERIAL ACTIVITY OF LEPTADENIA HASTATA ON SOME SELECTED BACTERIA
The phytochemical analysis and antibacterial activities of the ethanol, methanol and aqueous (cold water) extracts of the leaves of Leptadenia hastata were investigated against some selected pathogenic bacteria which include Escherichia coli, Salmonella typhi, Staphylococcus aureus and Pseudomonas aeruginosa at 62.5, 125, 250 and 500mg/ml concentrations using Agar well diffusion method. The leaves were plucked, air dried, macerated, soaked, filtered and evaporated to dryness to obtain the extracts. Chloramphenicol (125mg/ml) was used as the standard drug for positive control to determine the sensitivity of the test organisms. The results of the antibacterial activity showed that the ethanol extract is the most effective followed by the methanol extract and then the aqueous extract which is the least effective with higher zones of inhibition on E. coli and S. typhi. The MIC result showed that the MIC of the ethanol leaf extract for S. aureus, S. typhi and E. coli was 125mg/ml, while for P. aeruginosa was 250mg/ml. The MIC of the methanol leaf extract for all the test organisms was 250mg/ml. However, the MIC of the aqueous leaf extract for both S. typhi and S. aureus was 250mg/ml, the MIC for E. coli was 125mg/ml and 500mg/ml for P. aeruginosa. The MBC result showed that the MBC of the ethanol extract on both S. aureus and P. aeruginosa was 500mg/ml and 250mg/ml for both E. coli and S. typhi. The MBC of the methanol extract on S. aureus, P. aeruginosa and S. typhi was 500mg/ml while the MBC for E. coli was 250mg/ml. However, the MBC investigations of the aqueous leaf extract on S. aureus, S. typhi and E. coli
was 500mg/ml while there was growth in all the methanol extract concentrations studied on P. aeruginosa thus no MBC result was obtained for P. aeruginosa. The result of the phytochemical analysis showed the presence of Tanins, Alkaloids, Flavonoids, Reducing sugar, Cardiac glycoside and Phlobatanins in all the extracts. Saponin was present in only the methanol extract, while Anthracenes were present only in the ethanol extract. Steroids and Anthraquinones were absents in all the extracts.