Antibacterial Activity of Methanolic Extracts of Euphorbia heterophylla and Tithonia diversifolia against Some Microorganisms

Aims: To determine the antibacterial activities of methanolic extracts of Euphorbia heterophylla and Tithonia diversifolia on clinical isolates.

Place and Duration of Study: The study was carried out at Afe Babalola University and the plants were collected from the campus. The isolates used were collected from Ekiti State University Teaching Hospital, Ekiti state.

Methodology: Methanolic extracts of Euphorbia heterophylla and Tithonia diversifolia leaves were obtained by cold extraction method. The activity of the extracts were tested on Staphylococcus aureus from skin, Staphylococcus aureus from infection of the respiratory tract (RTI), Klebsiella pnuemoniae, Streptococcus pneumoniae, Escherichia coli, Pseudomonas aeruginosa and Salmonella typhi using agar well diffusion technique on Mueller Hinton Agar.

Results: For Euphorbia heterophylla, the extract had greatest activity on Salmonella typhi. The diameter of the zone of inhibition at 100 mg/ml was 25.00 mm and 17.00 mm at 30 mg/ml. The least activities were recorded for Streptococcus pnuemoniae and Escherichia coli. The extract did not show activity against Staphylococcus aureus (RTI). The Minimum lethal Concentration (MLC) was between 80 mg/ml and 100 mg/ml. For Staphylococcus aureus (skin), Klebsiella pnuemoniae, Staphylococcus aureus (RTI) and Pseudomonas aeruginosa, it was 80 mg/ml. For Streptococcus pneumoniae, and Escherichia coli, it was 100 mg/ml. The methanolic extract of Tithonia diversifolia showed greatest activity on Pseudomonas aeruginosa. The diameter of zone of inhibition was 30.00 mm at 100 mg/ml and 15.00 mm at 30 mg/ml. The least activity was recorded for Klebsiella pnuemoniae. The zone of inhibition was 20.00 mm at 100 mg/ml and 13.00 mm at 30 mg/ml. The minimum lethal concentration (MLC) for Klebsiella pnuemoniae, Escherichia coli and Pseudomonas aeruginosa were 80 mg/ml. It was 100 mg/ml for Staphylococcus aureus (skin) and Staphylococcus aureus (RTI).

Conclusion: Extracts of Euphorbia heterophylla and Tithonia diversifolia showed activities on some microorganisms including Pseudomonas aeruginosa and Salmonella typhi. This is in agreement with the use of these plants in folkore medicine in the treatment of typhoid fever, wounds and boils.