In vitro antifungal effect of combined extracts of Euphorbia hirta L. And Carica papaya L.

Abstract

Trichophyton rubrum accounts for up to 69.5 % of all dermatophyte infections worldwide including ringworms (Tinea). High costs of treatment, drug resistance, side effects and increasing incidences of such fungal infections necessitated the need to develop newer antifungal agents that can address these issues. Studies have shown that most herbs are used as mixtures which offers a number of benefits which may result in an additive, potentiated or inhibitory effect. This study was an experimental study design carried out at Makerere University, College of Veterinary medicine, animal resources and biosecurity and Natural chemotherapeutic Research Institute.The antifungal activity of the combined extracts of Carica papaya L. and Euphorbia hirta L. at different ratios against Trichophyton rubrum was evaluated and the Minimum Inhibitory Concentrations (MIC) determined. From these data the fractional inhibitory concentrations (FIC) were determined together with the corresponding Fractional Inhibitory concentration (FIC) index and thereafter interpretations made on the nature of interactions. MIC for C. papaya ethanolic extract was 0.5mg/ml while for E. hirta ethanolic extract was at 0.25mg/ml. Minimum inhibitory concentration for C. papaya diethyl ether extract was 1mg/ml while for E. hirta diethyl ether extract 0.5mg/ml. From the MIC observed, the ethanolic extracts of both C.papaya and E.hirta demonstrated the highest activity as demonstrated by their low MIC. The results indicated two key findings. Ratios of E. hirta to C. papaya of 9:1, 8:2,5:5, 4:6,2:8,1:9 indicated indifference/additivity with a mean FICI of 1.32 while ratios of 7:3,6:4 and 3:7 indicated synergism (Eucast 2000) with a mean FICI of 0.22. 25% The results reveal that both E. hirta and C. papaya have synergistic antifungal activity against T. rubrum when in specific combinations.