Studies in the biochemistry of micro-organisms

Abstract

THE following metabolic products, present in the metabolism solution of Penicillium griseo-fulvum Dierckx when this mould is grown under different cultural conditions and on different culture solutions, have been isolated in this laboratory: 6-hydroxy-2-methylbenzoic acid [Anslow & Raistrick, 1931], 2:5-dihydroxybenzoic acid (gentisic acid), fumaric acid and mannitol [Raistrick & Simonart, 1933] and fulvic acid, C14H1208, a yellow crystalline substance of at present undetermined molecular constitution [Oxford et al. 1935].The purpose of the present communication is to record observations on a hitherto undescribed chlorine-containing metabolic product of P. griseo-fulvum which has been isolated from the mycelium of this mould and for which the name griseofulvin is proposed.Griseofulvin, C17H.706C,M.P. 218-219', is a colourless, crystalline, neutral compound giving no colour with FeCl3 and containing no free hydroxyl or carboxyl groups.It is highly dextrorotatory, [ac],61+ 417g.One oxygen atom is present as >CO since a crystalline mono-oxime, C,7H1806NC1, was readily obtained; derivatives are also formed with phenyl- hydrazine and with 2:4-dinitrophenylhydrazine, but these could not be obtained crystalline.The function of three other oxygen atoms is obvious since griseofulvin contains three methoxyl groups.A study of the products obtained on acid and alkaline hydrolysis showed that griseofulvin must be the methyl ester of a carboxylic acid, and hence the function of a fifth oxygen atom is accounted for.The function of the sixth oxygen atom has not been definitely settled though evidence given later indicates that it is present as an oxygen bridge.Griseofulvin, when hydrolysed with boiling N aqueous-alcoholic H2SO4, yields griseofulvic acid, C16H1506C1, [x]5461+ 5080, a monobasic acid containing two methoxyl groups and giving only a feeble colour with FeCl3, but these facts in themselves are not sufficient to establish the presence of the grouping -COO.CH3.However, hydrolysis of griseofulvin, or further hydrolysis of griseofulvic acid, with boiling aqueous N/2 NaOH yields norgriseofulvic acid, C15H130O6C1, [a]05M+609', a dibasic acid containing only one methoxyl group, together with decarboxygriseofulvic acid, C,5H1504C1, [x]e1 -310, an insoluble neutral compound containing two methoxyl groups, giving no colour with FeCl3, and derived from griseofulvic acid by the loss of 1 mol. of CO2.Decarboxygriseofulvic acid is stable to acid hydrolysis and hence it seems certain that griseofulvin contains only one -COO.COH3 group and that the second acidic ( 240 )