Carbazomycins G (I) and H (II), new congeners of the carbazomycin complex, have been isolated from the culture broth of Streptoverticillium ehimense. They have proved to contain a unique quinol moiety in the molecule. Their structures have been elucidated by mass and NMR spectrometries and X-ray crystallographic analysis. Carbazomycin G showed moderate antifungal activity against Trichophyton species.In a previous paper1}, we have reported the isolation of carbazomycins C, D, E and F as the minor components of carbazomycin complex. The structures of carbazomycins C (IV) and D (V) were determined by spectroscopic and chemical means, and in the present paper are confirmed by an X-ray crystallographic analysis of IV.In our successive search for other active substances produced by the same microorganism, we have found two new components named carbazomycins G (I) and H (II) which are shown to possess a unique quinol moiety in the molecule. In this paper, we report the isolation, physico-chemical and antimicrobial properties, and structure elucidation of I and II by mass,^-H and 13C NMRspectrometries and X-ray crystallographic analysis. The confirmation of the structures of IV and V by X-ray crystallography of IV is also reported.Results and Discussion Isolation of Carbazomycins G and H Streptoverticillium ehimense was cultured in the same wayas reported previously0. The broth filtrate was extracted with ethyl acetate and the extract was fractionated by silica gel columnchromatography using the solvent composed of «-hexane and ethyl acetate (7 : 1~1 : 1). The last fraction eluted with «-hexane and ethyl acetate (1 : 1) was concentrated and further purified by repeated preparative TLCon precoated Silica gel plates (Merck Art. No. 5715) developed with «-hexane and ethyl acetate (2 : 3). Under a UV-light (365 nm), I gave strong blue fluorescence and n gave dark yellow one, and both components gave the same brownish purple color on silica gel TLCby heating after spraying with 10 % sulfuric acid.

No abstract

The carbazomycins were isolated from Streptoverticillium ehimense H 1051 MY10 as the first antibiotics containing a carbazole nucleus and they mainly inhibit the growth of phytopathogenic fungi3'40. The complex consists of eight components; carbazomycins B (1), A, C, D, E, F, G and H, and their structures were elucidated by spectroscopic and chemical means together with X-ray crystallographic analyses4~7) and are shown in Fig. 1. The