Antifungal activity of ethanolic extracts of Ocimum gratissimum and Vernonia amygdalina leaves against dermatomycotic agents isolated from domestic animals in South Eastern Nigeria

Abstract

Dermatomycoses, often caused by both dermatophytic and non dermatophytic fungi, affect the epidermis, nail, and hair. There is an increase in antifungal resistance against antimycotics of many dermatophytes and non-dermatophytes, and this has posed a serious global challenge. Therefore, the search for effective and easily consumable new substances with antimycotic activity is of great necessity. This study aims to isolate dermatomycotic agents from domestic animals and evaluate, using ethanolic leaf extracts of Ocimum gratissimum and Vernonia amygdalina, the in vitro antifungal profile of these extracts against these isolates. A total of 698 domestic animals (dogs, sheep, goats, and pigs) were examined for skin lesions suggestive of dermatomycosis and skin scrapings collected. The agar well diffusion assay was used to evaluate the in vitro activity of both leaf extracts using voriconazole and their solvent, dimethyl sulfoxide (DMSO), as control positive and negative respectively. Results showed that among the fungal positive cultures, dermatophytes (5) and non-dermatophytes (55) were observed. These isolates except Penicillium spp. showed activity with ethanolic leaf extracts of O. gratissimum (128 μg/ml) and V. amygdalina (128 μg/ml) and were susceptible also to the positive control voriconazole (0.03 μg/ml). Therefore, the main dermatomycotic agents isolated from domestic animals in South Eastern Nigeria were Microsporum spp., Trichophyton spp., Aspergillus spp., and Penicillium spp., and these were susceptible to O. gratissimum and V. amygdalina at 128 μg/ml. The study confirms that these extracts exhibit antifungal activity to these dermatomycotic agents excluding Penicillium spp., and as they were cheap, less toxic, safe natural product, and readily available, they are preferred to synthetic drugs.