Extraction and purification from Ceratonia siliqua of compounds acting on central andperipheral benzodiazepine receptors

The presence of molecules with high affinity for central and peripheral benzodiazepine receptors was determined in the pod and leaves of Ceratonia siliqua carob. The amount of the substances able to selectively bind the central benzodiazepine receptor recovered fromcarob pods and leaves was respectively 12.17 and 18.7 ng diazepam equivalentg. The amount of compounds active on peripheral benzodiazepine receptor in both pods and leaves was higher in comparison with the central one, being 49.83 and 40.00 PK 11195 equivalentg, respectively. In particular the compounds acting on peripheral benzodiazepine receptors were found to be extremely concentrated in the young leaves Ž2572.57 ng PK 11195equivalentg. The presence of substances with central benzodiazepine activity in carob extracts seems of great importance in view of the possibility to use carob extract as potential natural products with anxiolytic-sedative effects. Moreover, the prevalence in leaves ofsubstances acting on peripheral benzodiazepine receptor suggests the possible utilisation of leave extracts as chemopreventive agents.