Curcumin and piperine supplementation of obese mice under caloric restriction modulates body fat and interleukin-1β

Abstract

Background: Dietary bioactive compounds capable of improving metabolic profiles would be of great value, especially for overweight individuals undergoing a caloric restriction (CR) regimen. Curcumin (Cur), a possible anti-obesity compound, and piperine (Pip), a plausible enhancer of Cur's bioavailability and efficacy, may be candidate agents for controlling body fat, metabolism and low grade inflammation.

Methods: 47 eight-week-old male C57BL/6 mice were fed a high fat diet (HFD) for 23 weeks to induce obesity. Then, mice were divided into 5 groups. Group 1 continued on HFD ad libitum. The other 4 groups underwent CR (reduced 10% HFD intake for 10 weeks, 20% for 20 weeks) with Cur, Pip, Cur + Pip or none of these. Percent body fat, plasma inflammatory markers associated with obesity (interferon (IFN)-γ, interleukin (IL)-10, IL-12 p70, IL-1β, IL-6 and KC/GRO), plasma Cur metabolites and liver telomere length were measured.

Results: Compared to the other groups, obese mice who underwent CR and received Cur + Pip in their diet lost more fat and had significantly lower IL-1β and KC/GRO. Tandem mass spectrometry analysis of plasma from obese mice under CR showed no difference in Cur metabolite levels between groups supplemented with Cur alone or combined with Pip. However, plasma IL-1β levels were inversely correlated with curcumin glucuronide. Minor modulation of telomere length were observed.

Conclusions: It is plausible that supplementing the high fat diet of CR mice with Cur + Pip may increase loss of body fat and suppresses HFD induced inflammation. Combination of Cur and Pip has potential to enhance CR effects for the prevention of metabolic syndrome.

Keywords: Caloric restriction; Curcumin; Glucuronide; High fat diet; Inflammation; Meso scale discovery; Metabolic syndrome; Obesity; Piperine; Tandem mass spectrometry.

Fig. 1

Chemical structures of spice compounds, curcumin (Cur) and piperine (Pip)

Fig. 2

Experimental design of the present study. CR, Caloric restriction; Cur, Curcumin; HFD, High-fat diet; HPLC-MS/MS, Chromatography with tandem mass spectrometry; MRI, Magnetic resonance imaging; MSD, Meso scale discovery; Pip, Piperine

Fig. 3

a-e Body weight and % of total body fat in each group. Body weight measured once a week, percent adiposity was measured by MRI every two weeks. a Group 1 high-fat diet (HFD), b Group 2 (HFD+ caloric restriction (CR)), c Group 3 (HFD + CR+ curcumin (Cur)), d Group 4 (HFD + CR+ piperine (Pip)), e Group 5 (HFD + CR + Cur + Pip). Data were expressed as mean values. f Comparison of total percent body fat (area under the curve (AUC)) of each groups measured during the phase 3 (20% CR, n = 9–10). *P < 0.05 compared to Group 1 by Dunn’s multiple comparisons test. Data were expressed as mean ± standard deviations (SD)

Fig. 4

Effect of CR and bioactive components of spice on plasma inflammatory cytokines. Plasma interferon (IFN)-γ, interleukin (IL)-10, IL-12 p70, IL-1β, IL-6 and keratinocyte chemoattractant / human growth-regulated oncogene chemokines (KC/GRO) were measured by multiplex kit by meso scale discovery (MSD). Detailed analytical conditions are described in the materials and methods section. Each box plot shows the maximum (top of the vertical line), 75th percentile (top of the box), median (middle line in the box), 25th percentile (bottom of the box), and minimum (bottom of vertical line) values of data (n = 5). *P < 0.05 represents significant differences between Group 1 high-fat diet (HFD) and Group 5 (HFD + caloric restriction (CR) + curcumin (Cur) + piperine (Pip)) by Dunn’s multiple comparisons test

Fig. 5

Chromatography with tandem mass spectrometry (HPLC-MS/MS) analysis of curcumin (Cur) metabolism. a Plasma curcuminoids were analyzed by HPLC-MS/MS with 18 kinds of MRM (Cur, m/z 367 > 134; curcumin glucuronide (CurG), m/z 543 > 134; curcumin sulfate (CurS), m/z 447 > 134; curcumin glucuronide sulfate (CurGS), m/z 623 > 134; curcumin diglucuronide (CurDG), m/z 719 > 134; curcumin disulfate (CurDS), m/z 527 > 134; dihydrocurcumin (DHCur), m/z 369 > 135; tetrahydrocurcumin (THCur), m/z 371 > 135; hexahydrocurcumin (HHCur), m/z 373 > 179; octahydrocurcumin (OHCur), m/z 375 > 179; dihydrocurcumin glucuronide (DHCurG), m/z 545 > 135; tetrahydrocurcumin glucuronide (THCurG), m/z 547 > 135; hexahydrocurcumin glucuronide (HHCurG), m/z 549 > 179; octahydrocurcumin glucuronide (OHCurG), m/z 551 > 179; dihydrocurcumin sulfate (DHCurS), m/z 449 > 135; tetrahydrocurcumin sulfate (THCurS), m/z 451 > 135; hexahydrocurcumin sulfate (HHCurS), m/z 453 > 179; octahydrocurcumin sulfate (OHCurS), m/z 455 > 179). Typical chromatograms for all MRM combined and three MRM representatives (CurG, CurGS, and Cur) were shown. Detailed analytical conditions are described in the materials and methods section. b Plasma CurG concentrations of high-fat diet (HFD) + caloric restriction (CR) + Cur and HFD + CR + Cur + piperine (Pip) groups were plotted. Each box plot shows the maximum (top of the vertical line), 75th percentile (top of the box), median (middle line in the box), 25th percentile (bottom of the box), and minimum (bottom of vertical line) values of data (n = 9–10)

Fig. 6

Liver telomere length measured using a real-time PCR based assay. The relative telomere length was expressed as the ratio of telomere repeat:single copy gene (T:S ratio). A standard curve prepared from mouse genomic DNA (Promega, WI) was present in every plate and was used to quantitate the telomere or single copy gene in the samples (n = 9–10). Data were expressed as mean ± standard error of the mean (SEM). P values between each groups were confirmed by Dunn’s multiple comparisons test