The present invention relates to a composition comprising extracts of Gramineae plant that improves cell viability under hypoxic conditions by inhibiting apoptosis. Thus, the extract of Triticum aestivum L., one of the Gramineae plant, of the present invention, in particular, prevents damage of brain, heart and kidney in animal models of ischemic diseases, and it also improves memory in an animal model of Alzheimer's disease. Therefore, a composition comprising extracts of Gramineae can be used as therapeutic agents or health care foods for preventing and treating ischemic diseases and degenerative brain diseases.