Occurrence of pharmacologically active benzodiazepines in trace amounts in wheat and potato.

Aqueous acid extracts of wheat grains and of potato tuber were found to contain a series of compounds displaying a high affinity to the central type benzodiazepine receptor (BZR) in mammalian brain. Further analysis using different HPLC systems, as well as mass spectrometry and gas chromatography combined with mass spectrometry lead to the identification of compounds belonging to the classical 5-phenyl-1,4-benzodiazepinones. In wheat grains diazepam, N-desmethyldiazepam, delorazepam, deschloro-diazepam, delormetazepam, lormetazepam and isodiazepam were identified, while potato tuber contained diazepam, N-desmethyldiazepam, delorazepam, lorazepam and delormetazepam. The concentration of the benzodiazepines (BZ) was in the low ppb range. Their biosynthesis most probably takes place in the plant tissue. The availability of BZs in plant nutritives points to a possible source for the previously reported presence of BZ in brain and peripheral tissues of several animal species and man.