Identification of PPAR-activating compounds in herbal and edible plants and fungi from Vietnam

Obesity is a major health problem in the world, and it relates to type2-diabetes, heart disease and stroke. The peroxisome proliferator-activated receptors (PPARs) including PPARα PPARδ and PPARγ are important regulators of lipid metabolism and display activities which are linked to preventing diseases associated with metabolic syndrome. Synthetic ligands for PPARs, and particularly PPARδ are being evaluated in their effectiveness in treatment of metabolic syndrome. However several of those ligands display serious side effects. Intake of fruits and vegetables is suggested as an important natural alternative to prevent obesity and metabolic syndrome. In this study it was investigated whether these preventive activities can be related to the presence of natural PPAR ligands, with a possible better activity profile and fewer side effects. For that matter we focused on medicinal plants, on fungi, and on common food items from Vietnam. An extraction and workup method was developed to extract PPAR ligands from these natural sources. The extracts were tested using human cell-based PPARα PPARγ and PPARδ reporter assays. PPAR agonistic activity was found in almost all of the sample extracts, albeit with largely different activity levels. Interestingly, high PPARδ agonistic activities were found in several medicinal plants and in particular in fungi, which may thus provide a natural resource of PPAR agonists in the diet, which may be involved in preventing obesity and metabolic syndrome in the Vietnamese population.