Benzodiazepine-like molecules, as well as other ligands for the brain benzodiazepine receptors, are relatively common constituents of plants.

The presence of benzodiazepine (BZD)-like molecules as well as of other substances with affinity for the brain BZD-receptors was explored in eight non-flowering plants known to contain biflavonoids, three flowering plants used as sedatives in folkloric medicine and one plant extensively used in Argentina, Uruguay, Brazil and Paraguay as a tea substitute. All the plants examined contained substances which bound to the central BZD-receptors and the majority of them also had BZD-like compounds detected by their specific interaction with a monoclonal antibody against BZDs. In various cases this last type of compound was present in amounts which exceeded trace levels (0.5-1.0 ng/g). The biological or clinical significance for humans of all these substances should be explored.