the present invention is based in part on the surprising discovery that tanshinones from salvia miltiorrhiza act as allosteric high - potency n - methyl - d - aspartate receptor antagonists . pharmacological blockade of excessive activation of n - methyl - d - aspartate receptors greatly reduces ischemic injury of neurons in cell culture and animal models . tanshinones thus represent a novel class of compounds with nmda receptor blocking activities with potential for the development of safe neuroprotective drugs for therapy of stroke and other neurodegenerative and neuropsychiatric disorders .