Helicascolide C, a new lactone from an Indonesian marine algicolous strain of Daldinia eschscholzii (Xylariaceae, Ascomycota)

Abstract

From an endophytic Daldinia eschscholzii strain isolated from the agar-producing red alga Gracilaria sp. SGR-1, collected from the coast of South Sulawesi, Indonesia, a new lactone helicascolide C (1) was obtained as colourless crystals from the ethyl acetate extract together with the related structurally known compound helicascolide A (2). The structure of the new compound 1 reveals a carbonyl group replacing an alcohol group of compound 2. The structure of 1 was elucidated by X-ray diffraction and spectral analyses. Compound 1 showed fungistatic activity against the phytopathogenic fungus Cladosporium cucumerinum.