Studies in the biochemistry of micro-organisms. 90. Alternariol and alternariol monomethyl ether, metabolic products of Alternaria tenuis

Although species of Alternaria, in the Dematiaceae family of moulds, are of common occurrence and of world-wide distribution, little work had been published until recently on their biochemical activities.Brian, Curtis, Hemming, Unwin & Wright (1949) reported that several strains of A. 8Olani (E. and M.) Jones and Grout and one strain of A. porri (Ell.)Sacc.produce, in a variety of liquid media and in fair yields, a metabolic product which they named alternaric acid.This substance, which is not appreciably antibacterial, has a remarkably specific antifungal activity and is phytotoxic.The same workers and Jefferys (Brian et al. 1951) determined the optimum conditions for the produc- tion and isolation of alternaric acid and gave a more detailed account of its antifungal properties.They showed that while germination ofthe spores of some fungi, e.g.Ab8idia glauca and Myrothecium verru- caria, is prevented by 1 pg./ml. of alternaric acid, concentrations as high as 100 ,ug./ml.are required to prevent the germination ofthe spores of other fungi, e.g.Botryt?s allii, although, with this fungus, I953