Anti-candidal activity of Aspergillus flavus IBRL-C8, an endophytic fungus isolated from Cassia siamea lamk leaf

Abstract

An endophytic fungus, Aspergillus flavus IBRL-C8 was isolated from leaf of a medicinal plant Cassia siamea Lamk. This isolated fungus was cultivated in the medium which has enriched with water extract of host plant then incubated at 30°C with 120 rpm for 20 days. After incubation period, the fermentative broth medium which contained the extracellular compounds secreted by the fungal biomass into the medium will be extracted with ethyl acetate. This extract showed significant inhibition zone against Candida albicans cells. The minimal inhibitory concentration (MIC) showed 1.0 mg/mL and its exhibited yeastocidal activity. The time-kill curve study was performed at three different extract concentrations (1/2MIC, MIC and 2MIC) and the results showed that the C. albicans cell growth was concentration dependent. The extract concentration lower than MIC value showed yeastostatic activity and at concentration higher than the MIC value it showed yeastocidal activity. Further detail of the effect of the ethyl acetate extract on the C. albicans cell was observed from the scanning electron microscopy and transmission electron microscopy photomicrographs which revealed severity of morphological deterioration experienced by the extract treated cells were beyond repair.