Benzastatins A, B, C, and D: new free radical scavengers from Streptomyces nitrosporeus 30643. I. Taxonomy, fermentation, isolation, physico-chemical properties and biological activities.

In the course of screening for free radical scavengers, rare metabolites, benzastatins A and B having aminobenzamide skeleton and benzastatins C and D having tetrahydroquinoline skeleton, were isolated from the culture broth of streptomyces nitrosporeus 30643. They showed inhibitory activity against lipid peroxidation in rat liver microsomes. In the cell assay, benzastatins C and D inhibited glutamate toxicity in N18-RE-105 cells with EC50 values of 2.0 and 5.4 microM, respectively.