Antimicrobial Activity of the Asclepias syriaca L. Root Extract

Asclepias syriaca L. is an invasive plant in Serbia which threatens the biodiversity and ecosystem functionality with its high production of wind-dispersed seeds and the rapid proliferation by the lateral rhizomes. The mechanism that allows its competitiveness is allelopathy - the release of the chemical compounds identified in the roots and leaves which have negative effects on the other plants. These allelochemicals not only affect the development of the neighboring plants, but also are a potential source of the antioxidant and antimicrobial compounds, which increase the immunity of the plant itself, protecting it from the pests and the pathogens. The present study aimed to screen the antifungal activity of the A. syriaca water and methanol extracts. In vitro antimicrobial activity was analyzed by the radial growth assays against the three phytopathogenic fungi isolates: Alternaria alternata, Fusarium avenaceum and Discula platani. The results were processed by factorial ANOVA and the statistically significant differences were determined by Duncan’s multiple range test using the software STATISTICA 13.5. The obtained results suggest that the A. syriaca water extract has a significant fungistatic and potential fungicidal effect towards the tested phytopathogenic fungi and thus can be considered as a potential tool for their biological control.