Fuligopyrones from the Fruiting Bodies of Myxomycete Fuligo septica Offer Short-Term Protection from Abiotic Stress Induced by UV Radiation

Abstract

The myxomycete Fuligo septica, colloquially referred to as "dog vomit fungus", forms vibrant yellow fruiting bodies (aethalia) on wood chips during warm and humid conditions in spring. In 2018, ideal climatic conditions in Sydney, Australia, provided a rare opportunity to access abundant quantities of F. septica aethalia, which enabled the isolation, purification, structure elucidation, and biological screening of two avenalumamide pyrones, fuligopyrone (1) and fuligopyrone B (2). While 1 and 2 did not exhibit any appreciable biological activity, their significant UV absorption at 325 nm suggested they may be acting as transient sunscreens to help protect the fruiting mass from exposure to sunlight. In support of this hypothesis, exposing a solution of 2 to direct sunlight for 5 min resulted in rapid equilibration with a mixture of 2E,4Z-fuligopyrone B (10) and 2Z,4E-fuligopyrone B (11) photoisomers.

A Survey of Recently Discovered Naturally Occurring Organohalogen Compounds

“…While this metabolite lacks appreciable biological activity, its significant UV absorption at 325 nm suggests that fuligopyrone B may act as a natural sunscreen. 173 The fungus Curvularia lunata BCC76963, which was collected from a Thailand Gramineae plant, contains the new phenylacetic acid derivative 4′-chlorocurvulin (372). 174 The mushroom Ganoderma mbrekobenum was collected on a wood sample in a rice field in Thailand and found to contain 11 undescribed lanostane triterpenoids, one of which 373 is a chlorohydrin.…”

“…The myxomycete Fuligo septica , which grows on wood chips in warm, humid weather, produces the new fuligopyrone B ( 371 ) along with a nonchlorinated analogue. While this metabolite lacks appreciable biological activity, its significant UV absorption at 325 nm suggests that fuligopyrone B may act as a natural sunscreen . The fungus Curvularia lunata BCC76963, which was collected from a Thailand Gramineae plant, contains the new phenylacetic acid derivative 4′-chlorocurvulin ( 372 ) …”