Grifolin, an antibiotic from a basidiomycete.

Extensive research concerning the antibiotics obtained from Basidiomycetes is being carried out (1, 2) but, in comparison with products from Penicillia, Aspergilli, Actinomyces, and bacteria, the chemical nature of only a few has as yet been clarified. Furthermore, none has been of practical use, owing to strong toxicity or weak activity. Kubo and Mizuno (3) have discovered that an ant.ibiotic is produced by Grijola con&ens (local name, “maitake” or ‘Lmasugoke”) (Fig. l), which we have extracted in a pure state and have named “grifolin.” The present paper deals mainly with its chemical structure. Grifolin is soluble in most organic solvents but insoluble in water. It is fairly st.able towards acid and alkali, but with increasing alkali concentration the solution acquires a purple-red color and resinifies when heated in a 10 per cent alkali solution. Grifolin, though inactive against Gram-negative bacteria such as Bacillus anlhracis, Bacillus dysenteriae, and Salmonella typhimurium, was active against Staphylococcus aureus (I: 200,000) and Bacillus subtilis (1: 180,000) ; the sensitivity of acid-fast bacteria (Mycobacterium avium, Mycobacterium phlei) to this substance is especially noteworthy. The toxicity is low, the minimum lethal dose for mice being 1.6 gm. per kilo, body weight. The activity is still retained when grifolin is heated to 200”. Analysis and molecular weight determinations established the empirical formula of grifolin as C1:H2,0,. The presence of two hydroxyl groups was demonstrated by esterification with p-nitrobenzoyl chloride. Catalytic reduction revealed the presence of three double bonds. Ozonolysis gave the dimer of acetone peroxide, carbon dioxide, acetone, levulinic aldehyde, and acetic acid. Since the fragment containing the hydroxyl groups seemed to be rather unstable, the p-nitrobenzoyl ester was likewise submittel to ozonolysis, whereby a water-insoluble product, C20H1809N2, colorless needles from ethanol, m.p. 216”, was obtained. This product appeared to contain two p-nitrobenzoyl groups and an aldehyde group. As lead tetraacetate reacts with free grifolin with the formation of methylet’hyl ketone, it seemed probable that this product had the structure I.