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. 2016 May 20;60:29418.
doi: 10.3402/fnr.v60.29418. eCollection 2016.

Long-term Antihypertensive Effect of a Soluble Cocoa Fiber Product in Spontaneously Hypertensive Rats

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Free PMC article

Long-term Antihypertensive Effect of a Soluble Cocoa Fiber Product in Spontaneously Hypertensive Rats

Sandra Fernández-Vallinas et al. Food Nutr Res. .
Free PMC article

Abstract

Background and methods: This study evaluates the antihypertensive effect of long-term intake of a soluble cocoa fiber product (SCFP). Different doses of SCFP were evaluated (200, 400, and 800 mg/kg/day) and a dose of 800 mg/kg/day of beta-glucan 0.75 (BETA-G) was used as a standard fiber. Water, a neutral vehicle, was used as negative control, and 50 mg/kg/day captopril was used as positive control. Systolic blood pressure (SBP) was measured weekly by the tail cuff method. Body weight, food, and liquid intake were also registered weekly in the rats from 10 to 24 weeks of life. Glucose, total cholesterol, and triglyceride levels; redox status; and the angiotensin-converting enzyme activity were also studied in the plasma samples of these animals.

Results: Throughout the 10 weeks of treatment, captopril and SCFP (400 mg/kg/day) demonstrated blood pressure lowering effects in the spontaneously hypertensive rats (p<0.05; n=8). Paradoxically, neither the highest dose (800 mg/kg/day) of SCFP decreased SBP nor 800 mg/kg/day BETA-G (p>0.05; n=8). When the corresponding antihypertensive treatment, was disrupted the SBP values of the 400 mg/kg/day SCFP treated animals returned to control values (p>0.05; n=8). In addition, the SCFP significantly decreased (p<0.05; n=4) the glucose, cholesterol, and triglyceride levels and also the liver and plasma malondaldehyde levels. Moreover, the SCFP slightly increased the reduced glutathione levels in the liver.

Conclusion: The SCFP could be used to control the blood pressure of hypertensive subjects for a long period of time and could improve metabolic complications associated to cardiovascular diseases.

Keywords: angiotensin-converting enzyme; antioxidant properties; blood pressure; fiber; spontaneously hypertensive rats.

Figures

Fig. 1
Fig. 1
Systolic blood pressure (SBP) of spontaneously hypertensive rats. The animals consumed different fluids from the 10th week of life until the 20th weeks of life (T=treatment period, indicated by a white bar) and received different daily treatments: tap water (○), 50 mg/kg/day captopril (□), 200 mg/kg/day soluble cocoa fiber product (SCFP) (♦), 400 mg/kg/day SCFP (■), 800 mg/kg/day SCFP (▲), and 800 mg/kg/day beta-glucan 0.75 mm (BETA-G) (x). The rats consumed tap water from the 20th week of life until the 24th week of life (F=follow-up period, indicated by a black bar). Data are mean values±SEM for 8 animals in T and for 4 animals in F. p estimated by two-way ANOVA and Bonferroni test (p<0.05). Similar letters represent no statistical differences.
Fig. 2
Fig. 2
Histograms of plasma glucose levels (mg/dl) from spontaneously hypertensive rats. The animals consumed different fluids from the 10th week of life until the 20th weeks of life (T=treatment period) and received different daily treatments: tap water (□), 50 mg/kg/day captopril (■), 200 mg/kg/day soluble cocoa fiber product (SCFP) (formula image), 400 mg/kg/day SCFP (formula image), 800 mg/kg/day SCFP (formula image), and 800 mg/kg/day beta-glucan 0.75 mm (BETA-G) (formula image). The rats consumed tap water from the 20th week of life until the 24th week of life (follow-up period=F). Data are mean values±SEM for 8 animals in T and for 4 animals in F. p estimated by one-way ANOVA and Bonferroni test between data from different groups, and by student t test on the same group at the end of T and at the end of F (p<0.05). Similar letters or symbols represent no statistical differences.
Fig. 3
Fig. 3
Histograms of plasma total cholesterol levels (mg/dl) from spontaneously hypertensive rats. The animals consumed different fluids from the 10th week of life until the 20th weeks of life (T=treatment period) and received different daily treatments: tap water (□), 50 mg/kg/day captopril (■), 200 mg/kg/day soluble cocoa fiber product (SCFP) (formula image), 400 mg/kg/day SCFP (formula image), 800 mg/kg/day SCFP (formula image), and 800 mg/kg/day beta-glucan 0.75 mm (BETA-G) (formula image). The rats consumed tap water from the 20th week of life until the 24th week of life (F=follow-up period). Data are mean values±SEM for 8 animals in T and for 4 animals in F. p estimated by one-way ANOVA and Bonferroni test between data from different groups, and by student t test on the same group at the end of T and at the end of F (p<0.05). Similar letters or symbols represent no statistical differences.
Fig. 4
Fig. 4
Histograms of plasma triglyceride levels (mg/dl) from spontaneously hypertensive rats. The animals consumed different fluids from the 10th week of life until the 20th weeks of life (T=treatment period) and received different daily treatments: tap water (□), 50 mg/kg/day captopril (■), 200 mg/kg/day soluble cocoa fiber product (SCFP) (formula image), 400 mg/kg/day SCFP (formula image), 800 mg/kg/day SCFP (formula image), and 800 mg/kg/day beta-glucan 0.75 mm (BETA-G) (formula image). The rats consumed tap water from the 20th week of life until the 24th week of life (F=follow-up period). Data are mean values±SEM for 8 animals in T and for 4 animals in F. p estimated by one-way ANOVA and Bonferroni test between data from different groups, and by student t test on the same group at the end of T and at the end of F (p<0.05). Similar letters or symbols represent no statistical differences.
Fig. 5
Fig. 5
Histograms of (A) plasma malondialdehyde (nmol MDA/ml plasma), and (B) liver malondialdehyde (µmol MDA/mg tissue protein) from spontaneously hypertensive rats. The animals consumed different fluids from the 10th week of life until the 20th weeks of life (T=treatment period) and received different daily treatments: tap water (□), 50 mg/kg/day captopril (■), 200 mg/kg/day soluble cocoa fiber product (SCFP) (formula image), 400 mg/kg/day SCFP (formula image), 800 mg/kg/day SCFP (formula image), and 800 mg/kg/day of beta-glucan 0.75 mm (BETA-G) (formula image). The rats consumed tap water from the 20th week of life until the 24th week of life (F=follow-up period). Data are mean values±SEM for 8 animals in T and for 4 animals in F. p Values estimated by one-way ANOVA and Bonferroni test between data from different groups, and by student t test on the same group at to the end of T and at the end of F (p<0.05). Similar letters or symbols represent no statistical differences.

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