Bamboo (Phyllostachys bambusoides) leaf extracts inhibit adipogenesis by regulating adipogenic transcription factors and enzymes in 3T3-L1 adipocytes

Abstract

In this study, the inhibitory effects of bamboo leaf extracts on adipogenesis were investigated by evaluating their activity against adipogenic transcription factors and enzymes in 3T3-L1 adipocytes. Bamboo leaf extracts significantly decreased triglyceride levels, and increased glycerol release in adipocytes. Cells treated with the water extract showed significantly higher glycerol release as well as lower triglyceride contents than those treated with the ethanol extract. Both bamboo leaf extracts significantly inhibited the expression of adipogenic transcription factors and enzymes, such as CCAAT/enhancer-binding protein α, sterol regulatory element binding protein 1c, peroxisome proliferator-activated receptor γ, acetyl-coenzyme A carboxylase, and fatty acid synthase, and increased the expression of phospho-adenosine monophosphate-activated protein kinase. These results show that bamboo leaf extracts inhibited adipogenesis in 3T3-L1 adipocytes and that the water extract was more efficacious than the ethanol extract.

Keywords: 3T3-L1; Adipocyte; Adipogenesis; Bamboo leaf; Obesity.

Fig. 1

Effect of bamboo leaf extracts on cell viability of 3T3-L1 adipocytes. Differentiated 3T3-L1 adipocytes were treated with various concentrations (0, 50, 100, 200, and 400 μg/mL) of bamboo leaf extracts and incubated for 72 h at 37 °C in a humidified incubator containing 5% CO₂. Each value is expressed as mean ± SD (n = 3). NS not significant, BE bamboo leaf ethanol extract, BW bamboo leaf water extract

Fig. 2

Effect of bamboo leaf extracts on Oil red O staining images (A) and triglyceride content (B) in 3T3-L1 adipocytes. Differentiated 3T3-L1 adipocytes were treated with different concentrations (0, 50, and 100 μg/mL) of bamboo leaf extracts and incubated for 8 days at 37 °C in a humidified incubator containing 5% CO₂. Each value is expressed as mean ± SD (n = 3). ^a–dValues with different letters are significantly different (P < 0.05) as analyzed using Duncan’s multiple range test. BE bamboo leaf ethanol extract, BW bamboo leaf water extract, HCA hydroxycitric acid

Fig. 3

Effect of bamboo leaf extracts on glycerol release in 3T3-L1 adipocytes. Differentiated 3T3-L1 adipocytes were treated with different concentrations (0, 50, and 100 μg/mL) of bamboo leaf extracts and incubated for 8 days at 37 °C in a humidified incubator containing 5% CO₂. Each value is expressed as mean ± SD (n = 3). ^a–cValues with different letters are significantly different (P < 0.05) as analyzed using Duncan’s multiple range test. BE bamboo leaf ethanol extract, BW bamboo leaf water extract, HCA hydroxycitric acid

Fig. 4

Effect of bamboo leaf extracts on the expression (A) and levels (B) of PPARγ, C/EBPα, and SREBP-1c in 3T3-L1 adipocytes. Western blot signal intensities were determined through densitometric analysis by using Multi Gauge V3.1 software. Representative blots are shown with expression levels quantified relative to those observed in untreated adipocytes. ^a–dValues with different letters are significantly different (P < 0.05) as analyzed using Duncan’s multiple range test

Fig. 5

Effect of bamboo leaf extracts on the expression (A) and levels (B) of FAS, ACC, and p-ACC in 3T3-L1 adipocytes. Western blot signal intensities were determined through densitometric analysis by using Multi Gauge V3.1 software. Representative blots are shown with expression levels quantified relative to those observed in untreated adipocytes. ^a–eValues with different letters are significantly different (P < 0.05) as analyzed using Duncan’s multiple range test

Fig. 6

Effect of bamboo leaf extracts on the expression (A) and ratio (B) of AMPK and p-AMPK in 3T3-L1 adipocytes. Western blot signal intensities were determined through densitometric analysis by using Multi Gauge V3.1 software. Representative blots are shown with expression levels quantified relative to those observed in untreated adipocytes. ^a–fValues with different letters are significantly different (P < 0.05) as analyzed using Duncan’s multiple range test