NK374200, a novel insecticidal agent from Taralomyces, found by physico-chemical screening.

In the course of a physico-chemical screening program, a novel microbial secondary metabolite with an adenine moiety was isolated from the culture broth of the fungus Taralomyces sp. The compound NK374200 had a novel peptidyl adenine nucleus. NK374200 was screened in various biological assay systems, and found to have anti-mosquito larval activity. In this report we describe the screening, isolation, structural elucidation and preliminary biological activities of NK374200. Physico-chemical screening for novel compounds with purine or pyrimidine moiety was attempted since these compoundswere previously reported to have various biological activities1^ As a first step, 50 filtrates offungal culture broth were applied to Dowex 50W x 8 (H+) and eluted with 1.4m NH4OHsolution respectively, since targeted compoundswere expected to be partially purified by this procedure. As the second step, each eluate was subjected to HPLC analysis under the following column conditions: Hewlett packard ODShypersil, temperature; 40°C, carrier; 5mMNH4OAcsolution with a linear MeCNgradient to 50%, flow rate; 0.3 ml/minute, detection; UVabsorption at 260nm. In this step, peaks which had the same retention times as knownmetabolites were omitted. As the third step, about 100 unidentified peaks were applied to 3 dimensional UV absorption spectrum analysis to detect the presence of a purine or pyrimidine moiety in a molecule. One peak showed the same UVspectrum as purine, and a compoundcorresponding to this peak was selected as a candidate and tentatively named NK374200. The producing strain had been isolated from a soil, and was identified as the fungus Taralomyces sp.