Culinary plants, herbs and spices – A rich source of PPARγ ligands

Obesity and the related disorders, diabetes, hypertension and hyperlipidemia have reached epidemic proportions world-wide. The influence of 70 plants, herbs and spices on peroxisome proliferators-activated receptor (PPAR)γ activation or antagonism, a drug target for metabolic syndrome, was investigated. Approximately 50 different plant extracts bound PPARγ in competitive ligand binding assay, including pomegranate, apple, clove, cinnamon, thyme, green coffee, bilberry and bay leaves. Five plant extracts transactivated PPARγ in chimeric GAL4-PPARγ-LBD system: nutmeg, licorice, black pepper, holy basil and sage. Interestingly, nearly all plant extracts antagonized rosiglitazone-mediated coactivator recruitment in time resolved fluorescence resonance energy transfer coactivator assay. The five transactivating extracts may function as selective PPARγ modulators (SPPARγMs), and the other extracts seem to be moderate antagonists or undetectable/weak SPPARγMs. As SPPARγMs improve insulin resistance without weight gain and PPARγ antagonists exert antiobesity action, a combination of these plants in diet could reduce obesity and the incidence of metabolic syndrome.