Effects and action mechanisms of berberine and Rhizoma coptidis on gut microbes and obesity in high-fat diet-fed C57BL/6J mice

Abstract

Gut microbes play important roles in regulating fat storage and metabolism. Rhizoma coptidis (RC) and its main active compound, berberine, have either antimicrobial or anti-obesity activities. In the present study, we hypothesize that RC exerts anti-obesity effects that are likely mediated by mechanisms of regulating gut microbes and berberine may be a key compound of RC. Gut microbes and glucose and lipid metabolism in high-fat diet-fed C57BL/6J (HFD) mice in vivo are investigated after RC and berberine treatments. The results show that RC (200 mg/kg) and berberine (200 mg/kg) significantly lower both body and visceral adipose weights, and reduce blood glucose and lipid levels, and decrease degradation of dietary polysaccharides in HFD mice. Both RC and berberine significantly reduce the proportions of fecal Firmicutes and Bacteroidetes to total bacteria in HFD mice. In the trial ex vivo, both RC and berberine significantly inhibit the growth of gut bacteria under aerobic and anaerobic conditions. In in vitro trials, both RC and berberine significantly inhibit the growth of Lactobacillus (a classical type of Firmicutes) under anaerobic conditions. Furthermore, both RC and berberine significantly increase fasting-induced adipose factor (Fiaf, a key protein negatively regulated by intestinal microbes) expressions in either intestinal or visceral adipose tissues. Both RC and berberine significantly increase mRNA expressions of AMPK, PGC1α, UCP2, CPT1α, and Hadhb related to mitochondrial energy metabolism, which may be driven by increased Fiaf expression. These results firstly suggest that antimicrobial activities of RC and berberine may result in decreasing degradation of dietary polysaccharides, lowering potential calorie intake, and then systemically activating Fiaf protein and related gene expressions of mitochondrial energy metabolism in visceral adipose tissues. Taken together, these action mechanisms may contribute to significant anti-obesity effects. Findings in the present study also indicate that pharmacological regulation on gut microbes can develop an anti-obesity strategy.

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1. Effects of RC and berberine on (a) body weight and (b) visceral adipose tissue weight in HFD mice.

“Normal”, normal chow diet-fed mice; “HFD”, high-fat diet-fed control mice; “berberine”, berberine-treated HFD mice; “RC”, Rhizoma coptidis-treated HFD mice. Data were expressed as Mean±S.D. (n = 10), *P<0.05, **P<0.01 vs. HFD controls.

Figure 2. Effects of RC and berberine on 16SrRNA gene relative expressions of (a) Bacteroides/total bacteria and (b) Firmicutes/total bacteria in feces of HFD mice.

“Normal”, normal chow diet-fed mice; “HFD”, high-fat diet-fed control mice; “berberine”, berberine-treated HFD mice; “RC”, Rhizoma coptidis-treated HFD mice. Data were expressed as Mean±S.D. (n = 6), *P<0.05, **P<0.01 vs. HFD controls.

Figure 3. Effects of RC and berberine on growth of fecal bacteria ex vivo under (a) aerobic and (b) anaerobic conditions.

“Normal”, normal chow diet-fed mice; “HFD”, high-fat diet-fed control mice; “Berberine”, Berberine-treated HFD mice; “RC”, Rhizoma Coptidis-treated HFD mice (n = 6).

Figure 4. Effects of (a) berberine and (b) RC on the growth of Lactobacillus sp. under anaerobic conditions in vitro.

Figure 5. Effects of RC and berberine on Fiaf protein expressions in intestinal and adipocyte tissues.

“Normal”, normal chow diet-fed mice; “HFD”, high-fat diet-fed control mice; “berberine”, berberine-treated HFD mice; “RC”, Rhizoma coptidis-treated HFD mice. Data were expressed as Mean±S.D. (n = 6), *P<0.05, **P<0.01 vs. HFD controls.

Figure 6. Effects of RC and berberine on gene expressions in visceral adipose tissues and livers.

“Normal”, normal chow diet-fed mice; “HFD”, high-fat diet-fed control mice; “berberine”, berberine-treated HFD mice; “RC”, Rhizoma coptidis-treated HFD mice. Data were expressed as Mean±S.D. (n = 6), *P<0.05, **P<0.01 vs. HFD controls.

Figure 7. HPLC fingerprint of ethanol extracts of Rhizoma coptidis (RC).

Chromatogram conditions: Kromasil C18 column (5 µm, 4.6 mm×250 mm), column temperature, 30°C; mobile phase, acetonitrile: H2O (0.05 M KH2PO4, pH 3.0) = 30∶70 (v/v); elution rate, 1 ml/min; detector wavelength, 345 nm. Peak “1”, berberine (content, 24.2%).