Metabolism and Antifungal Activity of Coumarin and its Derivatives

In the present article, the inhibitory activity against the postharvest fungi Lasiodiplodia spp., Botrytis spp., and Fusarium spp. of coumarin was evaluated.Coumarin exhibited a significant antifungal effect (at concentrations of 1.5 mM and above), with inhibition percentages ranging from 24.8% to 66.4% for Lasiodiplodia spp., 55.5% to 78.8% for Fusarium spp., and 75.6% to 88.9% for Botrytis spp.Additionally, the metabolism of coumarin by phytopathogenic fungi was studied.Coumarin was found to be transformed into two main metabolic products, which were purified by chromatographic techniques and identified by spectroscopic methods ( 1 H and 13 C NMR), corresponding to dihydrocoumarin and 3-(2hydroxyphenyl) propanoic acid.According to the structure of metabolic products, coumarin was hydrogenated at the carboncarbon double bond and the lactone system was opened, which affects the ,-unsaturated carbonyl system.Additionally, the effect of different substituents on both the aromatic ring and the , -unsaturated carbonyl system in the antifungal activity was evaluated.The results indicate that the presence of substituents such as 3-acetyl and 3-ethyl carboxylate on the double bond moiety significantly enhances the inhibitory effect on the radial growth of postharvest pathogen Lasiodiplodia spp.