SUBSTANCES PRODUCED BY FUNGI 183 



either by preliminary adsorption on norit followed by removal with 

 ether or chloroform, or by the direct treatment of the culture with ether. 

 The extract is evaporated, leaving a brown substance j this is treated 

 with a small amount of water, and the aqueous solution again extracted 

 with ether, Clavacin crystallizes when the ether solution is concentrated, 

 or after preliminary purification over a silica gel column. Clavacin thus 

 isolated (429, 473) from A. davatus cultures showed the following 

 chemical properties: melting point, 109-110° C.j empirical formula, 

 C7H6O4J molecular weight (cryoscopic in benzophenone) 154^ semi- 

 carbazone, darkens at 200°, decomposes at 290° C. j 2,4-dinitrophenyl- 

 hydrazone, darkens above 190°, decomposes at about 300° C. j lactone 

 group indicated by slow reaction with alkali; saponification number 70 

 (evidently molecule cleaved); Zerewitinoff determination (in ;?-butyl 

 ether) shows slightly less than one active hydrogen per mol; esterifica- 

 tion by the acetic anhydride-pyridine method shows one hydroxyl per 

 mol. Clavacin, a neutral optically inactive compound, darkens and 

 loses activity in the presence of alkali, reduces Fehling's solution 

 strongly on heating, and readily decolorizes alkaline permanganate; 

 it does not react with aqueous ferric chloride or Schiff's reagent, and re- 

 duces ammoniacal silver nitrate. 



Clavacin (patulin) is anhydro-3-hydroxymethylene-tetrahydro-Y- 

 pyrone-2-carboxylic acid, for which a formula has been suggested (713), 

 as shown in Figure 1 6. 



Clavacin is soluble in water and in most of the more common organic 

 solvents except light petroleum. It is about equally active against gram- 

 positive and gram-negative bacteria, its growth inhibition being about 

 200,000 dilution units. Its lethal action upon mice is about 25 mg. per 

 kilogram body weight, when given intravenously or subcutaneously. 



Claviformin isolated (114, 115) from P. clavijorme has recently 

 been shown to be identical with clavacin and patulin (47, 927). 



FuMiGACiN is produced by different strains of A. jumigatus. It can 

 be extracted from the culture medium either by preliminary adsorption 

 on active charcoal followed by treatment with ether and alcohol, or by 

 direct extraction of culture in accordance with the following method 

 (593): The culture filtrate is acidified to /)H 2 with phosphoric acid 

 and extracted three times with ether, the combined extracts equalling 



