Antimicrobial Properties of Euphorbia hyssopifolia and Euphorbia hirta against Pathogens Complicit in Wound, Typhoid and Urinary Tract Infections

Dehydrogenase activity (DHA) in Gram-positive Staphylococcus aureus isolated from degenerated wound, Gram-negative Salmonella typhi isolated from stool, and Gram-negative Escherichia coli from a high vaginal swab were assayed. Inhibition of dehydrogenase activity of the test organisms by ethanol extract of Euphorbia hyssopifolia, and Euphorbia hirta, were determined and compared to standard antibiotics (Ciprofloxacin and Gentamycin). The total dehydrogenase assay was done using 2, 3, 5-triphenyl tetrazolium chloride (TTC) as the artificial electron acceptor which was reduced to the red-coloured triphenyl-formazan (TPF). Response of the bacterial isolates varied with extract concentration. Dehydrogenase activity was progressively inhibited in a logistic dose-response fashion in the test organism by the extracts and standard drugs. All extract and standards achieved at least 70% inhibition within the tested doses (0-2000µg/ml), except for Euphorbia hirta against Staphylococcus aureus. Threshold inhibitory concentrations (IC50) for Euphorbia hyssopifolia against Staphylococcus aureus, Salmonella typhi and Escherichia coli were 59.92µg/ml, 234.90µg/ml, and 492.46µg/ml respectively, while for Euphorbia hirta IC50 against Salmonella typhi and Escherichia coli was 99.67µg/ml,and 165.90µg/ml with no significant inhibition against Staphylococcus aureus. Inhibition of dehydrogenase activity in the test organism by the extract compared well with the standard antibiotics. Euphorbia hyssopifolia was effective against Gram-positive Staphylococcus aureus implicated in delayed wound healing than Gram-negative Salmonella typhi and Escherichia coli implicated in typhoid fever and urinary tract infections respectively, while Euphorbia hirtawas effective against Gram-negative organisms implicated in typhoid fever and urinary tract infections, but not effective against Gram-positive Staphylococcus aureus. Secondary plant metabolites found in the extracts may be acting in synergy to bring about their pharmacologic functions and may explain reasons for ethno-medical usage.