Screening of Medicinal Plants for their Activities Against Cellular Targets Related to Inflammation and Metabolic Disorders

Medicinal plants are a rich source of ligands for nuclear receptors. The present study aimed to screen a collection of plant extracts for modulation of nuclear receptors such as PPARα, PPARγ and LXRα, which are considered as targets for diabetes, obesity and cardiovascular disease, through reporter gene assays. Selected plant extracts were further tested to find their effects on targets related to inflammation such as NF-κB, iNOS and COX-2 and cellular oxidative stress. Their effects on cellular glucose uptake and adipogenesis were also determined. Ethanolic extracts of 263 plant species, belonging to 94 families, were screened for activation of PPARα/(γ and LXRα. Twenty-five extracts showed activation of PPARα/(γ, out of which 13 extracts showed of LXRα activation. The extracts of three plants (A. montana, J. virginiana and O. vulgare) were found to inhibit iNOS, COX-2 and NF-κB expressions along with their property of LXRα and PPARα/(γ activation, suggesting their potential against inflammation and metabolic disorders. Thymelaea hirsuta and T. chebula, as PPARα/(γ dual agonists, retain the property of elevating glucose uptake without the undesired side effect of adipogenesis. This is the first report to reveal the PPARα/(γ and/or LXRα agonistic action of these plant extracts along with their anti-inflammatory or glucose uptake enhancing effect.