With the aim of developing lifestyle-related disease prevention and treatment remedy, we searched for nuclear receptor PPARγ activation resources from natural food resources using the reporter gene assay method, and found activity in roasted barley extract. After isolation and purification of the active compound using various types of chromatography, structural analysis was performed using spectrum data from NMR and MS spectrum, and it was revealed that it was cyclo (Pro-Phe) with a diketopiperazine skeleton. Since the presence of cyclo (L-Pro-D-Phe) has been reported in barley tea and most of the amino acids contained in barley tea are in the L form, the purified cyclo (Pro-Phe) was estimated to be composed of four types: L-Pro-L-Phe, L-Pro-D-Phe, D-Pro-L-Phe, and D-Pro-D-Phe. Therefore, after hydrochloric acid hydrolysis, we investigated the L and D content ratio using amino acid labeling method and found that they were Proline (L : D = 7 : 3) and Phenlyalanine (L : D = 5 : 1). Currently, we have synthesized four types of compounds and are evaluating their PPARγ agonist activity.
