GEX1 Compounds, Novel Antitumor Antibiotics Related to Herboxidiene, Produced by Streptomyces sp. I. Taxonomy, Production, Isolation, Physicochemical Properties and Biological Activities.

Abstract

Six structurally related antitumor antibiotics named GEX1 compounds were isolated from a culture broth of Streptomyces sp. GEX1A was identified as a known herbicide, herboxidiene, structurally interested by the tetrahydropyran moiety and the side chain including a conjugated diene. GEX1Q1-Q5 were determined as novel compounds related to herboxidiene. All GEX1 lines in vitro, but were not active against both Gram-positive and-negative bacteria. Though GEX1A/herboxidiene exhibited antitumor activity in murine tumor-planted mouse models, both GEX1Q3 and GEX1Q5 did not. In the course of a screening for new antitumor antibiotics, we isolated six structurally related compounds from a culture broth of Streptomyces sp. Among them, GEX1Q1, GEX1Q2, GEX1Q3, GEX1Q4 and GEX1Q5 are novel compounds. The major product, GEX1A was identified as a known herbicide, herboxidiene1). In this paper, the taxonomy of the producing strain, fermentation, isolation, and antitumor properties of GEX1 compounds are described. The structure determination of GEX1Q1-Q5 will be reported in elsewhere. Materials and Methods Microorganism The producing strain GEX1 compounds was isolated from a soil sample collected in Yamanashi prefecture, Japan. The strain has been deposited at the International

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