New Dihydroquinolinone Toxic to Artemia salina Produced by Penicillium sp. NTC-47

Penicillium sp. NTC-47, which had been isolated from a soil sample, produced novel dihydroquinolinones when cultured with okara (the insoluble residue of whole soybean). These metabolites, 1 and 2, were crystalline products with molecular formulas of C₁₇H₁₇NO₅ and C₁₇H₁₇NO₄, respectively. The structure of 1 was established to be 3-methoxy-4,5-dihydroxy-4-(4'-methoxyphenyl)-quinolinone by spectroscopic evidence and by an X-ray crystal-lographic analysis. Spectral data indicated the structure of 2 to be 5-deoxy-l. Compound 1 demonstrated toxicity against brine shrimp with an LC₅₀ value of 20μg/ml, but 2 exhibited no activity at a dose of 100 μg/ml.