Identity of Griseofulvin and ‘Curling-Factor’

Abstract

When Penicillium janczewskii is grown in liquid culture media a substance is produced which causes stunting, excessive branching and characteristic distortions in the germ tubes of Botrytis allii and other fungi1. The substance has been isolated and called ‘curling-factor’2. When some preliminary observations3 were made on the chemical and physical properties of curling-factor, the presence of chlorine was overlooked and a formula C20H20O9 was proposed. We find that chlorine is present and that curling-factor is identical with griseofulvin C17H17O6Cl, which was isolated several years ago by Oxford, Raistrick and Simonart4 from Penicillium griseofulvum (for curling-factor found: C 58·4; H 4·9 per cent; mol. wt. 362; OCH3 23·2; Cl 9·8 (micro) and 9·7 (macro) per cent; CH3—(C) 4·9 per cent; calculated for C17H17O6Cl: C 57·9; H 4·9 per cent; mol. wt. 352·7; OCH3 26·4 (for three OCH3); Cl 10·1; CH3—(C) 4·3 (for one CH3) per cent). The melting point (220°) of a sample of griseofulvin which was kindly supplied to us by Prof. Raistrick was not depressed by mixing with curling-factor (m.p. also 220°); and further, griseofulvin is identical with curling-factor in its biological properties5.