title: Oleuropein as an inhibitor of peroxisome proliferator-activated receptor gamma.
abstract: Oleuropein, the major phenolic compound found in olive leaves and oil, exerts antioxidant, anti-inflammatory and anti-atherogenic effects and suppresses the adipocyte differentiation in vitro. Herein, we characterized molecular mechanisms underlying the anti-adipogenic effects of oleuropein on 3T3-L1 cells and adipocytes derived from stromal-vascular fraction of dorsolumbar and gonadal fat dissected from mice. We found that oleuropein (>100 μM) decreased viability of preadipocytes proliferating in vitro and did not exerted any cytotoxic effects in post-confluent cells after induction of differentiation. Oleuropein (>100 μM) inhibited adipocyte differentiation, suppressed gene expression of peroxisome proliferator-activated receptor γ (PPARγ), CCAAT-/enhancer-binding protein α, sterol regulatory element-binding transcription factor 1c and fatty acid synthase. Furthermore, we tested ability of oleuropein to regulate of PPARγ-, PPARα- or PPARβ-/PPARδ-mediated β-lactamase expression in appropriate reporter gene assays. Oleuropein between 10 and 400 μM concentrations did not affect activity of PPARα or PPARβ/δ. Contrary, PPARγ activity, either basal or rosiglitazone activated, was inhibited by oleuropein. Our data suggest that oleuropein exerts anti-adipogenic effect through direct inhibition of PPARγ transcriptional activity.
authors: Department of Adipose Tissue Biology, Institute of Physiology, Academy of Sciences of the Czech Republic, v.v.i., Videnska 1083, 142 20, Prague 4, Czech Republic.
authors: Michaela
authors: M
authors: Svobodova
authors: Ioanna
authors: I
authors: Andreadou
authors: Alexios-Leandros
authors: AL
authors: Skaltsounis
authors: Jan
authors: J
authors: Kopecky
authors: Pavel
authors: P
authors: Flachs