Studies in the biochemistry of micro-organisms. 95. Rugulosin, a crystalline colouring matter of Penicillium rugulosum Thom

Abstract

Two crystalline coloring matters - one red and the other yellow - were isolated from the mycelium of laboratory cultures of a number of strains of P. rugulosum and from 1 strain of P. wortmanni. The red coloring matter is skyrin, C30H18O10, previously reported from P. islandicum. The yellow coloring matter, which has not been described previously and is named rugulosin, C30H22O10, forms yellow prisms, m.p. about 293[degree] (decomp.) which are strongly dextrorotatory. It has a markedly specific antibacterial activity and is moderately antifungal. Good yields of chrysophanol (4,5-dihydroxy-2-methylanthra-quinone) and emodin (4,5,7-trihydroxy-2-methylanthraquinone) have been obtained by degradation of rugulosin. Treatment of rugulosin with concentrated sulphuric acid at 140[degree] gives aurantio-rugulosin, C30H18O8, which is believed to be a substituted dianthraquinone. The structural relationship of rugulosin and rubroskyrin, C30H22O12 from P. islandicum, is discussed, as well as that of aurantio-rugulosin and iridoskyrin, C30H18O10, from P. islandicum. It is believed that rugulosin and rubroskyrin belong to a new class of coloring matters which, while not anthraquinones themselves, readily give rise to well-known polyhydroxy-anthraquinones.