Studies in the biochemistry of micro-organisms

isolated, by chloroform extraction of the dried mycelium of laboratory cultures of the plant pathogen Helminthosporium gramineum, Rabenhorst, two hitherto undescribed polyhydroxyanthraquinones which they named helminthosporin and hydroxyisohelminthosporin. Later, Raistrick et al. [1934] isolated hydroxyisohelminthosporin from H. velutinum Link, H. tritici- vulgaris Nisikado and H. catenarium Drechsler, and since this polyhydroxyanthra- quinone occurs in only relatively small amounts in the mycelium of H. gramineum but is the main coloured product of H. catenarium it was re-named catenarin. More recently, Anslow & Raistrick [1940, 1] showed by analytical methods that catenarin is 1:4:5:7-tetrahydroxy-2-methylanthraquinone (V) and we have now confirmed this conclusion by synthesis.