12 



Quinones and Related Compounds 



Quinones occur widely in nature, and this topic has been re- 

 viewed.^- -■ ■"' Even allowing for their conspicuousness due to 

 color, solubility characteristics and (often) quantity, it seems 

 that they are broadly distributed among plants, and fungi are 

 no exceptions. 



Anthraquinones, in particular, have been isolated frequently 

 from fungus cultures. Some 80 anthraquinones and related 

 substances of known structure were listed by W. Karrer'^ as hav- 

 ing been reported from plant sources in general. About half of 

 this number have been isolated and characterized from fungi 

 and lichens. Since no anthraquinones have been reported from 

 algae, it may be that those present in lichens are formed pri- 

 marily by the fungus component. There is some evidence, how- 

 ever, that in lichens both partners are required for the biosyn- 

 thesis of depsides and depsidones.^ 



In fungi anthraquinones occur mainly in the mycelium, often 

 as mixtures of closely related materials. It is likely, for this 

 reason, that some of the quinones reported in the early litera- 

 ture were impure. 



The frequent identification of anthraquinone pigments in 

 molds has caused some speculation on their function. Argu- 

 ments in favor of a biological function have been summarized 



^ S. Shibata, Kagaku (Science) 26 391-396 (1956). 



~ R. H. Thomson, "Naturally Occurring Quinones," Academic 

 Press, New York, 1957, 302 pp. 



' W. Karrer, "Konstitution und Vorkommen der Organischen 

 Pflanzenstoffe," Birkhauser Verlag, Basel, 1958. 



* Dieter Hess, Zeitschr. Naturforsch. 14b 345 (1959). 



