Isolation, Antifungal Activity, and Structure Elucidation of the Glutarimide Antibiotic, Streptimidone, Produced byMicromonosporacoerulea

Abstract

The antibiotic Ao58A,which showed strong antifungal activity against some plant pathogenic fungi, was purified from the culture broth and mycelial mats of Micromonospora coerulea strain Ao58 using various chromatographic procedures. The molecular formula of the antibiotic Ao58A was deduced to be C(16)H(23)NO(4) (M + H, m/z 294.1707) by high-resolution FAB mass spectroscopy. Analyses of (1)H NMR, (13)C NMR, and 2D NMR spectral data revealed that the antibiotic Ao58A is the glutarimide antibiotic streptimidone, 4-(2-hydroxy-5, 7-dimethyl-4-oxo-6,8-nonadienyl)-2,6-piperidinedione. The antibiotic Ao58A was very effective in inhibiting growth of Phytophthora capsici,Didymella bryoniae, Magnaporthe grisea, and Botrytis cinerea in the range approximately 3-10 microg mL(-)(1) of MICs. In vivo evaluation of the antibiotic Ao58A under greenhouse condition showed strong control efficacies against the development of P. capsici, B. cinerea, and M. grisea on pepper, cucumber, and rice plants, respectively. The antibiotic Ao58A was equally as effective as metalaxyl, vinclozolin, and tricyclazole in the control of these plant diseases. However, it did not show any phytotoxicity on the plants even when treated with 500 microg mL(-)(1).

Isolation and In Vivo and In Vitro Antifungal Activity of Phenylacetic Acid and Sodium Phenylacetate from Streptomyces humidus

“…It is interesting that Streptomyces strains continue to provide a larger number and wider variety of new antibiotics than any other actinomycete genus, suggesting that substantial numbers of Streptomyces species or strains with novel antibiotic productivity exist in nature (27). In searches for bioactive antibiotics, Streptomyces strains have been isolated from various types of soils, including rice paddy, lake mud and water, deciduous forest, tropical forest, wasteland, and cave soils (9,16,19,30,31,34).So far, various antifungal antibiotics active against the oomycete plant pathogen Phytophthora have been isolated and characterized from actinomycetes (2,12,13,15,(20)(21)(22)(23). In our previous search program for microorganisms producing antifungal antibiotics useful for the control of plant diseases, Streptomyces humidus strain S5-55 was isolated from soils in Korea, which showed substantial antagonistic activity against plant pathogens (25).…”

“…So far, various antifungal antibiotics active against the oomycete plant pathogen Phytophthora have been isolated and characterized from actinomycetes (2,12,13,15,(20)(21)(22)(23). In our previous search program for microorganisms producing antifungal antibiotics useful for the control of plant diseases, Streptomyces humidus strain S5-55 was isolated from soils in Korea, which showed substantial antagonistic activity against plant pathogens (25).…”

Chlorinated organic compounds produced byFusarium graminearum

“…1-{[chloro(dimethyl)silyl] methyl}-2,6-piperidinedione is similar to 4-(2-hydroxy-5,7-dimethyl-4-oxo-6,8-nonadienyl)-2,6-piperidinedione which was found to be an antifungal agent produced by Micromonospora coerulea strain Ao58 [8]. The production of 1-{[chloro(dimethyl)silyl]methyl}-2,6-piperidinedione by F. graminearum may imply that this compound is used by this fungus to inhibit the growth of other fungal competitors.…”

Antiproliferative and antibacterial activity of some glutarimide derivatives

“…Isolation and examination of pharmacologically active natural glutarimides started in 1960s. Initially, cycloheximide 9 and streptimidone [10][11][12] were examined as antibiotics, but later it was found that they acted as very potent cytotoxic agents 13,14 . The structurally related streptimidone derivative, 9-methylstreptimidone, exerts a significant inhibitory activity toward nuclear factor-kB (N-kB) 15 .…”