Scytalidin: a new fungitoxic metabolite produced by a Scytalidium species

Abstract

A new fungitoxic metabolite, designated scytalidin. was isolated from culture medium which had supported growth of Scytalidium sp., an imperfect fungus. The structure (3) of scytalidin (1 0-butyl-5,9,10,11 -tetrahydro-I 0hydroxy-4-pentyl-4H-cyclonona[1,2-c:5.6-c']difuran-l,3.6,8-tetraone) was established on the basis of spectrometric and chemical investigations. The metabolite is related structurally and biosynthetically to the nonadrides.A SPECIES of Scytalidium, FY strain, was observed by Ricard and his collaboratorsl~~ to be antagonistic to Poria carbonica, a wood-rotting organism responsible, ivcter alia, for heartwood decay in Douglas-fir utility poles in western North America. Metabolites produced by Scytalidium sp. were isolated, and included yellow and red pigments, as well as a colourless compound, m/e 348-42809. Antifungal activity was found to be associated with the crystalline red and colourless substances.1*2 Scytalidium sp., FY strain, has been further investigated in our laboratory. When grown in a synthetic medium in liquid-shake culture, it produced at least two major metabolites which displayed antifungal proper tie^.^ Chemical investigation of one of these, a new compound for which the name scytalidin is proposed, forms the subject of this report.The molecular formula of scytalidin was established as C,,H,,O, by elemental analysis and high resolution mass ~pectrometry.~ 1.r. absorption (CHC1, solution) at 3575 cm-l was attributed to alcohol functionality, further characterized as a single tertiary hydroxy-group on the basis of the following observations. Scytalidin was recovered unchanged after treatment with Jones reagent.5 The metabolite was resistant to acetylation with acetic anhydride-pyridine ; it was, however, readily converted into a monoacetate by the action of acetic anhydride in the presence of zinc chloride.6 Comparison of the n.m.r. spectra of scytalidin and its acetate did not reveal any differences which could be attributed to a proton geminal to the hydroxy-group.' The n.m.r. spectrum of scytalidin in [2H,]dimethyl sulphoxide showed a downfield shift of the OH signal from 6 2.14 to 4-58 p.p.m., and, in accord with the tertiary nature of the hydroxy-function, the signal retained its singlet c h a r a ~t e r . ~~~ Scytalidin displayed i.r. bands (KBr) at 1850, 1827, and 1773 cm-l, and U.V. absorption [ A, , (acetonitrile)]

Microflore interne des tissus ligneux de l'épicéa commun sur pied

“…Certains représentants du genre Scytalidium ont montré des propriétés antibiotiques intéressantes notamment vis-à-vis du F. annosus (KUNGSTROM et al, 1965 ;STRUNZ et al, 1972, STII/WËEE et al, 1973. In situ, RICARD (1975) ine, it is a boring at 1.30 m).…”

Scytalone (3,6,8-Trihydroxytetralone), a Metabolite from a Scytalidium Species

“…In a recent paper Strunz et al (1) reported the isolation of several metabolites from a species of Scytalidiunz FY strain. The structure of one & of these was shown to be related to the nona- R2O OR3…”

Experience with immunizing commensals

“…This phenomenon was used to devise a control method (Ricard et al, 1969). The effect observed as well as the activity against other wood-inhabiting microorganisms (Stillwell et al, 1973) could be ascribed to the presence of scytalidic acid (Overeem and Mackor, 1973) or scytalidin (Strunz et al, 1972). The stability of this antibiotic also explained the apparent long-term effect of Scytalidium inoculations (Ricard, 1975).…”