Antibiotics from basidiomycetes. XI. The biological activity of siccayne, isolated from the marine fungus Halocyphina villosa J. & E. Kohlmeyer

From submerged cultures of the marine basidiomycete Halocyphina villosa we isolated siccayne (4-(2,4-dihydroxyphenyl)-2-methyl-1-buten-3-yne) (1), a metabolite first described from fermentations of the deuteromycete Helminthosporium siccans. Siccayne is a moderately active Antibiotic, which inhibits Gram-positive bacteria and some fungi at concentrations of 10 approximately 50 micrograms/ml. Its cytotoxic effect is much more pronounced on both normal and Rous-sarcoma-virus transformed chicken embryo fibroblasts as compared to cells of the Ehrlich ascites carcinoma. Siccayne apparently interferes with the uptake of nucleoside precursors into eucaryotic cells as well as with the in vitro incorporation of nucleotides into DNA and RNA.