Successive purification of a crude extract of cultured Mi Huan Jun mycelia, followed by an assay of the effect on complete ischemia in mice, led to the isolation of a new compound with cerebral protecting activity, hereafter designated as AMG-1. The structure of AMG-1 was proposed as being 6-(5-hydroxy-2-pyridyl-methylamino)-9-beta-ribofuranosylpurine (1) on the basis of its UV, mass, 1H-NMR, and 13C-NMR spectra.