The effects of strawberry bioactive compounds on lipid metabolism and adipogenesis

Abstract

Obesity is one of the major problems of the 21st century worldwide. It is characterized by an expansion of white adipose tissue (WAT) mass resulting from increased adipocytes number and/or size. Excessive accumulation of mature adipocytes is associated with high lipid levels and with a general impairment of catabolic pathways. In this work, we evaluated the effect of a strawberry extract on lipid metabolism and adipogenesis on HepG2 cells and 3T3-L1 adipocytes. The results demonstrated that in HepG2 strawberry extract stimulated the LKB1/AMPK pathway leading to the inactivation of acetyl coenzyme A carboxylase (ACC) and inhibition of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), the major regulators of fatty acids and cholesterol synthesis, respectively; it also stimulated LDL receptor, sirtuin 1 (Sirt1) and the peroxisome proliferator activated receptor gamma coactivator 1-alpha (PGC-1α). In addition, strawberry extract reduced 3T3-L1 pre-adipocytes differentiation, lipid accumulation and down-regulated the mRNA expression of the adipogenic transcription factors CCAAT/enhancer-binding protein (C/REB-α) and peroxisome proliferation-activated receptor (PPAR-γ). Consistently, it inhibited the expression of fatty acid binding protein (FABP4), ACC and sterol regulatory element-binding protein (SREBP1), by activating AMPK pathway. Strawberry extract also inhibited oxidative stress and inflammation biomarkers, increased antioxidant enzymes activities and mitochondrial functionality. Our results suggest the potential anti-obesity effect of the bioactive components of strawberry.