Allantopyrone E, a rare α-pyrone metabolite from the mangrove derived fungus Aspergillus versicolor

A new α-pyrone derivative, with a rare substitution pattern, was isolated from the solid rice media of the fungal endophyte Aspergillus versicolor associated with the fruit of the mangrove Avicennia marina. It was named allantopyrone E, after allantopyrones C and D. The aforementioned three are the only diaryl-substituted α-pyrones to be reported from nature. The unique structure was elucidated based on one- and two dimensional NMR data as well as high resolution mass spectroscopy. A biosynthetic scheme was proposed for the new compound. Furthermore, allantopyrone E showed cytotoxic effect on HeLa cells with IC₅₀= 50.97 μM.