BIOCHEMISTRY OF THE USTILAGINALES: VII. ANTIBIOTIC ACTIVITY OF USTILAGIC ACID

Abstract

The antibiotic activity of Ustilago zeae (PRL 119) cultures is associated mainly with the culture solids and it has been shown that a mixture of glucolipids, called ustilagic acid and produced in good yields by the fungus, is responsible for part, if not all, of the observed activity. The antibiotic activity of ustilagic acid corresponds to that originally attributed to ustizeain B and therefore these two are considered to be identical. All samples of ustilagic acid obtained showed antibiotic activity and it has not been possible by paper chromatography to separate an active principle from the acid. Recrystallization of ustilagic acid did not alter its antibiotic properties. Alkaline hydrolysis of the acid destroyed its activity. Heating the culture mixture for up to an hour at temperatures less than 100° C. did not alter materially the antibiotic properties of the mixture or of the acid extracted therefrom. The antifungal spectrum is broad and the antibacterial spectrum includes more Gram-positive than Gram-negative organisms. Preliminary tests with rats indicated that ustilagic acid is nontoxic when administered orally up to at least 5% of the diet, and with mice, orally up to at least 1% of the diet or intraperitoneally in amounts up to 1.5 gm. per kgm. of body weight.