Diazepam and N-desmethyldiazepam are found in rat brain and adrenal and may be of plant origin.

Benzodiazepine-binding inhibitory (BBI) activity was detected in aqueous extracts of brain and peripheral tissues of rats. The BBI activity in brain and in adrenals was, at least partially, due to the presence of N-desmethyldiazepam and diazepam as shown by HPLC, UV-spectroscopy and mass spectrometry. In addition, BBI activity was found in standardized rat food, as well as in a variety of cereals and in other nutritive plant products. In wheat grains diazepam and N-desmethyldiazepam could be identified by HPLC and analysis by gas chromatography combined with mass spectrometry. The estimated amounts of the two benzodiazepines present in rat brain and adrenals and in wheat grains were in the low ppb range. Since laboratory contamination was rigorously excluded we conclude that diazepam and N-desmethyldiazepam are naturally occurring compounds. These findings may explain their occurrence in the brain and adrenals of animals.