Effect of aqueous extract of leaf and bark of guava (Psidium guajava) on fungi Microsporum gypseum and Trichophyton mentagrophytes, and bacteria Staphylococcus aureus and Staphylococcus epidermidis

Abstract

In this study, we investigated the effects of P. guajava on organisms responsible for skin disorders, specifically the fungi: Microsporum gypseum and Trichophyton mentagrophytes, and bacteria: Staphylococcus aureus, and Staphylococcus epidermidis. The leaves and bark of the P. guajava plant was harvested from Obasa farm Ijero, Ekiti-State, Nigeria, during the beginning of rainy season in March, 2009. Aqueous solutions were obtained by grinding the leaves and the bark. Mueller-Hinton agar was used to grow the bacteria S. aureus and S. epidermidis. Sabouraud Dextrose broth was used to grow the fungi Trichophyton mentagrophytes and Microsporum gypseum. Analysis of the antibacterial action of the extracts of guava leaves and bark was carried out at different concentrations, by comparing the mean diameter of the inhibition haloes as a variable. Values were represented as mean ± S.E. An ANOVA Tukey’s test was performed to determine the mean difference between the control and the two treatments (S1 and S2). In comparing the tetracycline positive control to both solutions, tetracycline had a significantly (p < 0.05) stronger inhibition effect than both solutions. This could be due to the fact that tetracycline is a pure chemical while the P. guajava solutions were crude extracts. Both P. guajava solutions were effective against inhibiting the growth of bacteria S. aureus and S. epidermidis, and fungi M. gypseum and T. mentagrophytes. This supports the reported use of P. guajava in many countries as a traditional herbal medicine.

Keywords: Psidium guajava, Microsporum gypseum, Trichophyton mentagrophytes, Staphylococcus aureus, Staphylococcus epidermidis, tetracycline.