To obtain the subject new compound having inhibitory activity against glutamic acid toxicity, and useful as a neurocyte protective agent, cerebrocyte degeneration inhibitor or cerebrocyte necrosis inhibitor.

This new compound cu39 (salt) is shown by the formula, and obtained by culturing cu39-productive bacteria belonging to the genus Streptomyces: Streptomyces sp. cu39 strain (FERM BP-482). This compound has the following physicochemical properties: appearance: yellow powder; melting point : 184-186°C; solubility: readily soluble to ethyl acetate, acetone, chloroform, methanol, ethanol; Rf number: 0.2 (CHCl3: MeOH=50:1); HRFAB-MS spectrum: 379, 1182 (calculated); specific rotatory power:[α]21D, =2.5 (c=0.02, MeOH); and molecular formula: C22H18O6. The dose of the cu39 is 0.1-100mg per day per adult.