Anti-Adipogenic and Anti-Obesity Effects of Gongmi Tea and Gongmi So Extract

Abstract

The prevalence of obesity has been increasing worldwide, and its pathogenesis is closely related to preadipo-cyte differentiation. Because the presence of obesity increases the risk of chronic disease, it is important to decrease exces-sive body fat accumulation. This study aimed to demonstrate the anti-adipogenesis and anti-obesity effects of gongmi tea and gongmi so extract. The 3T3-L1 preadipocyte cell line was stained with Oil red O, and the expression levels of peroxi-some proliferator-activated receptor-γ (PPARγ), adiponectin, and fatty acid-binding protein 4 (FABP4) were evaluated via Western blot analysis. A mouse model of obesity was developed by feeding C57BL/6 male mice a high-fat diet (HFD). Gongmi tea or gongmi so extract was orally administered at a dose of 200 mg/kg for 6 weeks. The mouse body weight was measured weekly during the study period, and the epididymal adipose tissue weight and blood serum were analyzed at the end of the study period. The gongmi tea and gongmi so extract did not exhibit toxicity in mice. Oil red O staining showed that gongmi tea significantly decreased excessive body fat accumulation. In addition, gongmi tea (300 μg/mL) significantly downregulated adipogenic transcription factors, such as PPARγ, adiponectin, and FABP4. In vivo tests indicated that oral administration of gongmi tea or gongmi so extract to C57BL/6 mice with HFD-induced obesity effectively decreased their body weight and epididymal adipose tissue. Gongmi tea and gongmi so extract have potent in vitro anti-adipogenic effects in 3T3-L1 cells and in vivo anti-obesity effects in mice with HFD-induced obesity.

Keywords: herb medicine; high-fat diet; metabolic syndrome; obesity.

Fig. 1

Schematic of 3T3-L1 preadipocyte differentiation. Fully cultured 3T3-L1 cells were treated with 0.5 mM 3-isobutyl-1-methylxanthine, 1 μM dexamethasone, and 10 μg/mL insulin (MDI) for 2 days. The cell culture medium was changed with new 10 μg/mL of insulin-containing Dulbecco’s modified Eagle’s medium every 2 days. To investigate the effects of gongmi tea or gongmi so extract on adipogenesis, differentiated 3T3-L1 cells were treated every 2 days. After 8 days of differentiation, Oil red O staining and Western blot analysis were conducted.

Fig. 2

Effects of gongmi tea and gongmi so extract on cell viability. (A) Mouse splenocytes, (B) 3T3-L1 preadipocytes, and (C) MDI-treated 3T3-L1 preadipocytes were seeded in 96-well plates. The cells were treated with garcinia, gongmi tea, or gongmi so extract (100, 200, and 300 μg/mL) for 48 h. Cell viability was tested via MTS assay, and absorbance was measured at 490 nm. Gongmi tea and gongmi so extract did not exhibit cytotoxicity at concentrations of 100, 200, and 300 μg/mL. Data are expressed as mean±standard error of the mean. MDI, 3-isobutyl-1-methylxanthine, dexamethasone, and insulin; MTS, 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxy-methoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium.

Fig. 3

Effects of gongmi tea and gongmi so extract on lipid accumulation in adipocytes. The 3T3-L1 cell line was seeded in 6-well plates and grown to full confluence for 2 days. Then, the cells were treated with gongmi tea or gongmi so extract and differentiated into adipocytes via the MDI treatment. The differentiated adipocytes were treated with gongmi tea or gongmi so extract (100 and 300 μg/mL), and SB203580 and garcinia were used as positive controls. (A) Intracellular lipids were stained with Oil red O and then quantified. The administration of gongmi tea and gongmi so extract decreased lipid accumulation. (B) Stained lipid droplets were dissolved in 100% isopropanol, and absorbance was measured at 490 nm. Data are expressed as mean±standard error of the mean. ^###P<0.001 compared with the non-treated group. *P<0.05, **P<0.01, and ***P<0.001 compared with the MDI-treated group. MDI, 3-isobutyl-1-methylxanthine, dexamethasone, and insulin.

Fig. 4

Effects of gongmi tea and gongmi so extract on the protein expression of adipogenic transcription factors. The 3T3-L1 cell line was seeded in 6-well plates and grown to full confluence for 2 days. Adipocytes were treated with gongmi tea or gongmi so extract during differentiation. SB203580 and garcinia were used as positive controls. Cell lysates were isolated, and the protein expressions of peroxisome proliferator-activated receptor-γ (PPARγ), adiponectin, and fatty acid-binding protein 4 (FABP4) were determined via Western blot analysis. Glyceral-dehyde 3-phosphate dehydrogenase (GAPDH) was used as a loading control. MDI, 3-isobutyl-1-methylxanthine, dexamethasone, and insulin.

Fig. 5

Experimental design of a mouse model with high-fat diet (HFD)-induced obesity. Five-week-old C57BL/6 male mice were divided into five groups. The control group was fed a chow diet (n=6), whereas the experimental group was fed an HFD (60% kcal, n=24). The mice were orally administered gongmi tea or gongmi so extract (200 mg/kg) for 6 weeks, and their body weight and food and water consumption were monitored every week. After the study period, the mice were euthanized for analysis.

Fig. 6

Effects of oral administration of gongmi tea and gongmi so extract on body weight and epididymal adipose tissue weight in C57BL/6 mice fed high fat diet. Gongmi tea and gongmi so extract decreased adiposity in mice with high-fat diet (HFD)-induced obesity. (A) Body weight was measured once a week. (B, C) The epididymal adipose tissue was removed immediately and weighed. Data are expressed as mean±standard error of the mean (n=6). ^#P<0.05 and ^##P<0.01 compared with the control group. *P<0.05 and ***P<0.001 compared with the HFD group.

Fig. 7

Effects of oral administration of gongmi tea and gongmi so extract on kidney and liver damage in C57BL/6 mice fed high-fat diet (HFD). To evaluate nephro- and hepatotoxicity, the serum levels of (A) uric acid (UA), (B) creatinine (CRE), (C) blood urea nitrogen (BUN), (D) glutamic oxaloacetic transaminase (GOT), and (E) glutamic pyruvic transaminase (GPT) were analyzed after oral administration of gongmi tea or gongmi so extract for 6 weeks. Data are expressed as mean±standard error of the mean (n=6). ^#P<0.05 and ^##P<0.01 compared with the control group. *P<0.05 and **P<0.01 compared with the HFD group.