Olive Leaf Extract from Sicilian Cultivar Reduced Lipid Accumulation by Inducing Thermogenic Pathway during Adipogenesis

Rosa Palmeri,Giovanni Spagna,Marco Raffaele,Julieta I Monteleone,Luca Vanella,Giovanni Li Volti,Cristina Restuccia,Ignazio Barbagallo

doi:10.3389/fphar.2016.00143

Abstract

Olive leaves contain a wide variety of phenolic compounds belonging to phenolic acids, phenolic alcohols, flavonoids, and secoiridoids, and include also many other pharmacological active compounds. They could play an important role in human diet and health because of their ability to lower blood pressure, increase coronary arteries blood flow and decrease the risk of cardiovascular diseases. The aim of this study was to investigate the effect of olive leaf extract (OLE) from Sicilian cultivar on adipogenic differentiation of human adipose derived mesenchymal stem cells and its impact on lipid metabolism. We showed that OLE treatment during adipogenic differentiation reduces inflammation, lipid accumulation and induces thermogenesis by activation of uncoupling protein uncoupling protein 1, sirtuin 1, peroxisome proliferator-activated receptor alpha, and coactivator 1 alpha. Furthermore, OLE significantly decreases the expression of molecules involved in adipogenesis and upregulates the expression of mediators involved in thermogenesis and lipid metabolism. Taken together, our results suggest that OLE may promote the brown remodeling of white adipose tissue inducing thermogenesis and improving metabolic homeostasis.

Highlights

Olive leaves contain a wide variety of phenolic compounds belonging to phenolic acids, phenolic alcohols, flavonoids, and secoiridoids, and include many other pharmacological active compounds such as oleuropein (OE), hydroxytyrosol (HT), tyrosol, cumaric acid, ferulic acid, caffeic acid, vanillic acid, rutin, verbascoside, luteolin, quercetin, dimethyloleuropein, and ligstroside (Talhaoui et al, 2015)
It has been demonstrated that olive leaf extract (OLE) attenuates obesity in high-fat diet-fed mice by modulating the expression of molecules involved in adipogenesis and thermogenesis (Shen et al, 2014)
To investigate signals that might regulate the differentiation of ASCs, we analyzed the mRNA levels of PPARγ (Figure 2A), CCAAT/enhancer-binding protein alpha (CEBPα; Figure 2B), diacylglycerol O-acyltransferase 1 (DGAT1; Figure 2C), fatty acid binding protein 4 (FABP4; Figure 2D), fatty acid synthase (FAS; Figure 2E), and sterol regulatory element-binding protein 1c (SREBP-1c; Figure 2F)

Summary

Introduction

Olive leaves contain a wide variety of phenolic compounds belonging to phenolic acids, phenolic alcohols, flavonoids, and secoiridoids, and include many other pharmacological active compounds such as oleuropein (OE), hydroxytyrosol (HT), tyrosol, cumaric acid, ferulic acid, caffeic acid, vanillic acid, rutin, verbascoside, luteolin, quercetin, dimethyloleuropein, and ligstroside (Talhaoui et al, 2015). OE content, the major phenolic compound of olive leaves, varies from 17 to 23% (Le Tutour and Guedon, 1992) These phenolic compounds have a significant pleiotropic effects including antioxidant activity (Somova et al, 2003) as well as antimicrobial activity against Helicobacter pylori, Campylobacter jejuni, Staphylococcus aureus (Sudjana et al, 2009), and Bacillus cereus, Escherichia coli, and Salmonella enteritidis (Lee and Lee, 2010). They play an important role in human diet and health because of their ability to lower blood pressure, increase blood flow in the coronary arteries, and decrease the risk. This study demonstrates that OLE exerts beneficial effects against obesity by overexpressing sirtuin 1 (SIRT-1), peroxisome proliferatoractivated receptor alpha (PPARα), and peroxisome proliferatoractivated receptor gamma (PPARγ), coactivator 1 alpha (Pgc-1α)

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