Differential effects of a combination of Hibiscus sabdariffa and Lippia citriodora polyphenols in overweight/obese subjects: A randomized controlled trial

Abstract

Plant-polyphenols have shown the capacity to ameliorate obesity-induced metabolic disturbances, both in cell and animal models, where most therapeutic approaches have failed. On the basis of previous research, a dietary supplement containing 500 mg of a combination of polyphenolic extracts from Lippia citriodora L. and Hibiscus sabdariffa L. (LC-HS), in the context of an equilibrated isocaloric diet, was evaluated in a double blind, placebo-controlled and randomized trial in 56 obese/overweight subjects for two months. Compared to controls, the consumption of the LC-HS polyphenols showed significant improvements in body weight, abdominal circumference of overweight subjects (-6.79 ± 0.80 cm in overweight LC-HS group vs -1.85 ± 0.83 cm in controls, p < 0.001) and body fat % (-1.33 ± 0.15% in overweight LC-HS group vs -0.66 ± 0.17% in controls, p < 0.05). Heart rate and systolic blood pressure also presented significant improvements in overweight LC-HS participants. However, changes were more modest in obese subjects. Further, LC-HS extract significantly reduced lipid content and increased AMPK activity in a hypertrophied adipocyte cell model. Therefore, consumption of 500 mg/day of LC-HS extracts enriched in polyphenols for two months in the context of an isocaloric diet by overweight subjects decreased symptoms associated to obesity-related diseases. Modulation of fat metabolism in adipose tissue, probably mediated by AMPK activation, is proposed as a molecular target to be explored in future research.

Figure 1

Study design and flow chart of the double blind, placebo controlled and randomized trial using LC-HS combination in 56 overweight volunteers.

Figure 2

LC-HS combination decreases triglyceride accumulation and activates AMPK in hypertrophied 3T3-L1 adipocytes. Hypertrophied adipocytes were treated with a combination of the polyphenolic extracts, and triglyceride accumulation was monitored by AdipoRed staining as mentioned in the materials section (A). Hypertrophied adipocytes were treated with the same concentrations of the polyphenolic combination as in (A), and AMPK (non-active) and pAMPK (activated) kinases were quantitated by immunofluorescence microscopy (B). Representative photomicrographs of phase contrast, green fluorescence (AMPK), red fluorescence (pAMK) and overlay (C). The data are expressed as the mean ± S.D. from three independent experiments performed in octuplicate.

Figure 3

Representative HPLC chromatograms of the LC-HS combination at 320 nm for phenylpropanoids (upper panel) and 520 nm for anthocyanins (lower panel). Four compounds including delphinidin-3-O-sambubioside, cyanidin-3-O-sambubioside, verbascoside and isoverbascoside were determined by HPLC.