Studies on the constitution of edible and medicinal plants. I. Isolation and identification of 4-O-methylpyridoxine, toxic principle from the seed of Ginkgo biloba L.

A toxic substance, 4-O-methylpyridoxine, responsible for "gin-nan food poisoning" was isolated from seeds of Ginkgo biloba L. (Ginkgoaceae). It is proposed that the toxic principle causes food poisoning through not only antagonizing vitamin B6 in the body but also inhibiting the formation of 4-aminobutyric acid from glutamate in the brain.