A neuroprotective compound designated pyroxazone (1) was isolated from the culture broth of Streptomyces sp. RAN54. The molecular formula of 1 was established as C18H14N2O5 by high-resolution FAB-MS. The structure was determined to be a new 2-amino-3H-phenoxazin-3-one derivative by NMR spectroscopic analysis. Pyroxazone (1) protected C6 rat glioma cells and N18-RE-105 rat primary retina-mouse neuroblastoma hybrid cells from glutamate-induced toxicity with EC50s of 8.2 µM and 1.7 µM, respectively.