ANTIFUNGAL ACTIVITY OF Cymbopogon citratus AND SILVER NANOPARTICLES AGAINST Aspergillus niger, Aspergillus tamari and Mucor circinelloides

ABSTRACT

The continuous search for new antifungal substances against plant pathogens is important because of the negative effect chemical fungicides have on both the plant and the environment. The study was aimed at assessing the antifungal activities of Cymbopogon citratus aqueous and ethanolic extract individually and in synergy with silver nanoparticles (AgNP) against Aspergillus niger, Aspergillus tamari and Mucor circinelloides. The antifungal activity of silver nanoparticles (AgNP) alone was also assessed. Antifungal activities of Cymbopogon citratus, aqueous and ethanolic extract were performed using the food poisoning method. From the results, Cymbobogon citratus aqueous extract alone demonstrated strong activity against the pathogens with radial growth inhibition ranging from 35.00±4.00mm (Aspergillus niger, 75%), 36.14±1.44mm (Aspergillus tamari, 100%) and 65.83±12.83mm (Mucor circinelloides, 100%). This was significantly different from the controls 60.83±13.76mm for Aspergillus niger 80.00±0.00mm for Aspergillus tamari and 80.00±0.00mm for Mucor circinelloides. For the ethanolic extract of Cymbopogon citratus the mycelia radial growth inhibition ranged from 27.00±7.5mm (Aspergillus niger, 100%), 19.17±8.78mm (Aspergillus tamari, 25%) and 69.17±12.8mm (Mucor circinelloides, 25%). This was significantly different from the controls. AgNPs also demonstrated good activity in the inhibition of mycelia growth with radial growth inhibition ranging from 27.00±7.5mm (Aspergillus niger, 100%), 19.17±8.78mm. (Aspergillus tamari, 25%) and 69.17±12.8mm (Mucor circinelloides, 25%). The synergistic use of the aqueous extract or ethanolic extract of Cymbopogon citratus and AgNPs gave varying degrees of results against the pathogens. Further studies should be done to ascertain the risk posed by nanoparticles to human health before it should be used by farmers in the field.