Dictyoquinazols A, B, and C, new neuroprotective compounds from the mushroom Dictyophora indusiata

In an effort to identify neuroprotective compounds against excitatory neurotoxins from edible and medicinal mushrooms, dictyoquinazols A (1), B (2), and C (3) have been isolated from the methanolic extract of the mushroom Dictyophora indusiata. On the basis of NMR studies, their structures have been assigned as unique quinazoline compounds, which are very rare in nature. 2 and 3 existed as mixtures of rotamers (2a, 2b and 3a, 3b) inseparable by HPLC because of fast interconversion. The E/Z isomers of these compounds were assigned by comparison of ¹H NMR, ¹³C NMR, and NOESY spectra and by ³J_C.H coupling constants. Dictyoquinazols protected primary cultured mouse cortical neurons from glutamate- and NMDA-induced excitotoxicities in a dose-dependent manner.