Antimycotic and cytotoxicological potentials of Acacia mearnsii de wild. stem bark extract: In vitro assessment

Olufunmiso Olajuyigbe,Roger Coopoosamy,Morenike Adeoye-Isijola

doi:10.5937/kgjsci1941087o

Abstract

Despite using antimycotic drugs in the treatment of dermatomycoses as an age long practice, the fungicidal activities of indigenous plants on spores of dermatophytes from germinating in vitro need to be investigated further. In this study, methanol extract of Acacia mearnsii was assessed for its antifungal activity against dermatophytic pathogenic fungi by agar diffusion and broth dilution methods. The cytotoxicity activity of the extract was determined by the brine shrimp lethality assay. The study showed that the mean ± standard deviation of the inhibition zones ranged between 13 and 24 ± 0.58 mg/ml and the activity of the extract was concentration dependent. While the minimum inhibitory concentration (MIC) was 0.3125 - 2.5 mg/ml, the minimum fungicidal concentration (MFC) values ranged between 0.3125 mg/ml and 5 mg/ml. The susceptibility of the yeast to the extract was more than those of the molds. The MIC of the yeasts ranged between 0.3125 and 1.25 mg/ml while those of the molds ranged between 0.625 and 2.5 mg/ml. The mechanism of antibiosis showed that the extract was 7.69% fungistatic and 92.31% fungicidal wielding more killing effects on the fungi than potentiating their growth. The cytotoxicity assay showed that the crude methanolic extract with the LC50 being 101.59 µg/ml was pharmacologically active and nontoxic (LC50 > 100 μg/ml). The antifungal activity of this plant can be exploited as an alternative or complementary means of treating fungal infections to eliminate fungal spread. The study further justified the folkloric use of A. mearnsii in the treatment of a variety of microbial infections.

Highlights

Medicinal plants are a rich source of novel and powerful drugs (PONNUSAMY et al, 2010; YADAV et al, 2010)
While previously uncommon fungi which are difficult to manage and insidious opportunistic fungal infections caused by Aspergillus and Candida species are customarily accountable for the greater part of morbidity and mortality recorded in individuals undergoing haematopoetic stem cell transplantation (VISCOLI et al, 1999; GROLL and WALSH, 2001), the rising occurrence of fungal pathogens resistant to antifungal drugs has become a great concern (MANIKANDAN et al, 2011)
While the administration of systemic drugs has become therapeutically inadequate due to increased level of toxicity and associated problems of residues in products intended for human consumption (ARAÚJO et al, 2009), many aboriginal plants species widely described is being required for treatment of infections (LEE et al, 2007; VIGNESH et al, 2011)

Summary

Introduction

Medicinal plants are a rich source of novel and powerful drugs (PONNUSAMY et al, 2010; YADAV et al, 2010) They manufacture an extremely disparate series of secondary metabolites which increase with commencement of drought, outbreak of fire and bacterial infection (TAIZ and ZEIGER, 2006). Many in vitro studies on pharmacological relevance of medicinal plants have reported antifungal effects of many plants (PRUSTI et al, 2008; MOMTAZ and ABDOLLAHI, 2010). The effectiveness of these plants has been ascribed to the existence of a variety of phytochemicals. Being less toxic and not detrimental to human health (SATISH et al, 2009), bioactive compounds in plant extracts have become alternative to synthetic agents (KUMAR et al, 2010; OLAJUYIGBE et al, 2018)

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