Posidonia oceanica (L.) Delile Extract Reduces Lipid Accumulation through Autophagy Activation in HepG2 Cells.

Marzia Vasarri,Donatella Degl’Innocenti,Emanuela Barletta

doi:10.3390/ph14100969

Abstract

Posidonia oceanica (L.) Delile is a marine plant traditionally used as an herbal medicine for various health disorders. P. oceanica leaf extract (POE) has been shown to be a phytocomplex with cell-safe bioactivities, including the ability to trigger autophagy. Autophagy is a key pathway to counteract non-alcoholic fatty liver disease (NAFLD) by controlling the breakdown of lipid droplets in the liver. The aim of this study was to explore the ability of POE to trigger autophagy and reduce lipid accumulation in human hepatoma (HepG2) cells and then verify the possible link between the effect of POE on lipid reduction and autophagy activation. Expression levels of autophagy markers were monitored by the Western blot technique in POE-treated HepG2 cells, whereas the extent of lipid accumulation in HepG2 cells was assessed by Oil red O staining. Chloroquine (CQ), an autophagy inhibitor, was used to study the relationship between POE-induced autophagy and intracellular lipid accumulation. POE was found to stimulate an autophagy flux over time in HepG2 cells by lowering the phosphorylation state of ribosomal protein S6, increasing Beclin-1 and LC3-II levels, and decreasing p62 levels. By blocking autophagy with CQ, the effect of POE on intracellular lipid accumulation was clearly reversed, suggesting that the POE phytocomplex may reduce lipid accumulation in HepG2 cells by activating the autophagic process. This work indicates that P. oceanica may be considered as a promising molecule supplier to discover new natural approaches for the management of NAFLD.

Highlights

Posidonica oceanica (L.) Delile is a marine plant belonging to the Posidoniaceae family and the only species of Posidoniaceae endemic to the Mediterranean Sea [1]
HepG2 cells by promoting autophagy through inhibition of the mammalian target of rapamycin (mTOR) pathway
non-alcoholic fatty liver disease (NAFLD) is a metabolic condition commonly associated with type 2 diabetes mellitus and often combined with a chronic inflammatory state

Summary

Introduction

Posidonica oceanica (L.) Delile is a marine plant belonging to the Posidoniaceae family and the only species of Posidoniaceae endemic to the Mediterranean Sea [1]. Besides the extreme ecological importance of P. oceanica underwater meadows, the literature tells of a millenary relationship between humans and this marine plant. A decoction of P. oceanica leaves was used as an herbal medicine against diabetes and hypertension by inhabitants of coastal areas in Western Anatolia [4]. The literature describes antidiabetic and vasoprotective effects of a hydroalcoholic extract obtained from P. oceanica leaves in an in vivo animal model [4]. Our group has undertaken a series of in vitro and in vivo studies that for the first time shed light on the hitherto unexplored biological mechanisms underlying the bioactive properties of a hydroalcoholic P. oceanica leaf extract (POE).

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