Antioxidative Activity of Blueberry Leaf Extract Prevents High-fat Diet-induced Obesity in C57BL/6 Mice

Abstract

Background: Health beneficial effects of blueberry have been well documented. Obesity is health hazard that is associated with metabolic abnormalities. We investigated the effect of blueberry leaf extract (BBLE) on high-fat diet (HFD)-induced obesity in C57BL/6J mice.

Methods: C57BL/6 mice were fed HFD with or without BBLE for 10 weeks. Body weight, serum parameter, and adipose tissues morphology were assessed. The expression of mRNA associated with adipogenesis was measured using real-time polymerase chain reaction (RT-PCR) analysis.

Results: Administration of BBLE to mice challenged with HFD significantly decreased the body weight gain, the levels of plasma triglyceride (TG) and liver lipid peroxidation, and reduced the adipocyte size and improved hepatic status compared with the group treated with HFD only. BBLE treatment significantly improved glucose control compared with the HFD group. Moreover, BBLE showed an inhibitory effect on adipocyte differentiation in obese mice together with significant decrease in the lipid accumulation by downregulating gene expression of adipocyte-specific transcription factors, such as peroxisome proliferation-activity receptor and acetyl coenzyme A carboxylase and upregulating the mRNA expression of adiponectin, which are critical for adipogenesis.

Conclusion: BBLE suppressed the body weight gain in the HFD-fed C57BL/6 mice. Intake of BBLE reduced body weight in HFD-fed mice by 20%. Furthermore, BBLE supplementation significantly decreased the TG level in the liver and inhibited leptin secretion. BBLE supplementation also improved insulin resistance. Therefore, BBLE is a possible agent to prevent obesity.

Keywords: Adipocytes; Blueberry leaf extracts; High-fat diet-induced obesity.

Data are expressed as means ± s.d. (n = 6). ANOVA with Duncan’s test: ^*P < 0.01 significantly from the value of the HFD group. DW, distilled water.

Figure 1.

Effect of BBLE on tissue morphology. (A) Liver morphology (magnification ×400). (B) Epididymal adipose tissue morphology (magnification ×400). N, negative control mice; C, high-fat diet (HFD)-fed mice; PC, HFD-fed mice + catechin; B, HFD-fed mice + BBLE.

Figure 2.

Gene expression was determined by quantitative real-time polymerase chain reaction. ACC, acetyl coenzyme A carbox-ylase; PPAR-γ, peroxisome proliferator-activated receptor-γ; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; N, negative control mice; C, HFD-fed mice; PC, administration of catechin in HFD-fed mice; B, administration of BBLE in HFD-fed mice. Data are expressed as means ± s.d. (n = 6). Duncan’s test: *P < 0.01 significantly from the value of the HFD group.