Blueberry Peel Extracts Inhibit Adipogenesis in 3T3-L1 Cells and Reduce High-Fat Diet-Induced Obesity

Abstract

This study examined the anti-obesity effect and mechanism of action of blueberry peel extracts (BPE) in 3T3-L1 cells and high-fat diet (HFD)-induced obese rats. The levels of lipid accumulation were measured, along with the changes in the expression of genes and proteins associated with adipocyte differentiation in 3T3-L1 cells. Evidenced by Oil-red O staining and triglyceride assay, BPE dose-dependently inhibited lipid accumulation at concentrations of 0, 50, and 200 µg/ml. BPE decreased the expression of the key adipocyte differentiation regulator C/EBPβ, as well as the C/EBPα and PPARγ genes, during the differentiation of preadipocytes into adipocytes. Moreover, BPE down-regulated adipocyte-specific genes such as aP2 and FAS compared with control adipocytes. The specific mechanism mediating the effects of BP revealed that insulin-stimulated phosphorylation of Akt was strongly decreased, and its downstream substrate, phospho-GSK3β, was downregulated by BPE treatment in 3T3-L1 cells. Together, these data indicated that BP exerted anti-adipogenic activity by inhibiting the expression of PPARγ and C/EBPβ and the Akt signaling pathway in 3T3-L1 adipocytes. Next, we investigated whether BP extracts attenuated HFD-induced obesity in rats. Oral administration of BPE reduced HFD-induced body weight gain significantly without affecting food intake. The epididymal or perirenal adipose tissue weights were lower in rats on an HFD plus BPE compared with the tissue weights of HFD-induced obese rats. Total cholesterol and triglyceride levels in the rats fed BPE were modestly reduced, and the HDL-cholesterol level was significantly increased in HFD plus BP-fed rats compared with those of HFD-fed rats. Taken together, these results demonstrated an inhibitory effect of BP on adipogenesis through the down-regulation of C/EBPβ, C/EBPα, and PPARγ and the reduction of the phospho-Akt adipogenic factor in 3T3-L1 cells. Moreover, BPE reduced body weight gain and inhibited fat accumulation in an HFD-induced animal model of obesity.

Fermented blueberry juice extract and its specific fractions have an anti-adipogenic effect in 3 T3-L1 cells

“…In line with the inhibitory effect of fermented blueberry juice and its components, we found that F1 as well as sub-fractions F2 and F3-2 significantly inhibited the phosphorylation of Akt. This result is in line with the report by Song and collaborators who studied blueberry peel extracts and found an anti-adipogenic effect that was related to the inhibition of Akt phosphorylation [23]. …”

14 Days of supplementation with blueberry extract shows anti-atherogenic properties and improves oxidative parameters in hypercholesterolemic rats model

“…These data support the study of Song et al (2013) indicating that the BE can effectively regulate the metabolism of cholesterol and triglycerides in HFD-induced obese rats.…”

Effects of mulberry heartwood extract on genes related to lipid metabolism

“…Several studies demonstrated the potential of plant-derived compound or of total extracts to suppress adipogenesis in 3T3-L1 cells (6,9,10,16,21,32). Authors reported that polyphenols, phenolic acids and alkaloids added to the nu- (32). These effects are verified in vivo in experimental animals (14,32,35).…”

“…Authors reported that polyphenols, phenolic acids and alkaloids added to the nu- (32). These effects are verified in vivo in experimental animals (14,32,35). Some authors reported that leaves and fruits extracts of mulberry species have hypolipidemic effects probably due to the active components rich content (4, 22,25).…”