Determination of Antifungal Activity of Leaf Extracts from Hypericum ssp. Against Plant Pathogenic Fungi Fusarium oxysporum and Alternaria Alternata

Abstract

In this study, the antifungal activity of ethanol extracts of three plant species of Hypericum perforatum, Hypericum scabrum and Hypericum origanifolium were evaluated for against two plant pathogenic fungal species of Fusarium oxysporum and Alternaria alternata.The antifungal activities of Hypericum ssp. extracts (3, 15, 45, 80, 120, 200, 240, 300 ppm) were tested against fungi. Ethanol 30% as control; Commercial fungicide (1 ?g/mL) was used as a positive control. All Hypericum ssp. plant extracts were effective in different rates against the fungi depending on the doses. In addition, IC50 values of the three selected plant Hypericum ssp. leaf extract against pathogenic fungus F.oxysporum and A. alternata were determined with of probit analysis. In terms of the IC50 values, the antifungal activity of H. perforatum plant exract against F.oxysporum (122.525 ?g/mL) > A.alternata (108.484 ?g/mL). On the other hand, IC50 values of H. scabrum against A.alternata (126.390 ?g/mL) > F.oxysporum (113.714 ?g/mL). Moreover, the IC50 value of H. origanifolium against two pathogenic fungi was calculated as F.oxysporum (159.931 ?g/mL) > A.alternata (55.759 ?g/mL). Results showed that H.origanifolium has the best fungicidal activity, with IC50 value of 55.759 ?g/mL against A.alternata and H.scabrum 113.717 ?g/mL against F.oxysporum. However, the highest concentrations (300 ppm) caused completely inhibition in the both fungi mycelial growth followed by lower concentrations of plant extracts. A. alternata were the sensitive fungal species, while the F. oxysporum were a more resistant to the Hypericum ssp. extracts. Based on the antifungal activity tests, these plants extracts this may have effective as the new natural fungicide protecting crops against fungal diseases.