Phenazostatin C, a new diphenazine with neuronal cell protecting activity from Streptomyces sp.

glutamate toxicity inhibitors of microbial origin such as carquinostatin A,5) lavanduquinocin,6) and aestivophoenins A and B7) have been reported. In the course of our screening for free radical scavengers or inhibitors of glutamate toxicity using the neuronal hybridoma N18-RE-105 cells to prevent the brain ischemia injury, we previously isolated benzastatins A~G8~10) and phenazostatins A (2) and