Structural characterization, in-silico studies, and antifungal activity of 5-methylmellein isolated from endophytic Alternaria burnsii.

Abstract

The present investigation focused on exploring the potential of fungal endophytes as a valuable source of bioactive compounds with diverse applications. The phenolic compound 5-methylmellein was isolated for the first time from Alternaria burnsii, an endophytic fungus associated with Morus alba Linn. The compounds were structurally characterized using comprehensive spectral analysis, including 1H-, 13C, and 2D-NMR, as well as HRESI-MS. The study investigated the antifungal activity of 5-methylmellein against several plant pathogenic fungi, including Botrytis cinerea, Colletotrichum gloeosporioides, Cercospora beticola, and Rhizoctonia solani. In vitro assays showed significant inhibition of various plant pathogenic fungi, and the IC50 values ranging from 34.59 ± 1.03a µg/mL to 44.76 ± 1.03b µg/mL against the tested fungi. In vivo experiments on apples and grapes revealed that 5-Methylmellein significantly reduced fruit decay caused by Botrytis cinerea. The wound incidence in the control group reached 95.78%, while the treated groups exhibited a reduction of 37.54% after 15days. These findings underscore the potential of 5-methylmellein as a potent antifungal agent, suggesting its eco-friendly application in agriculture for managing fruit decay.