Antioxidant and Antiatherogenic Effects of Pomegranate

Antioxidant Effects

In a study by Aviram et al.,^[4] 13 healthy men age 20–35 years were given 50 mL of pomegranate juice (equal to 1.5 mmol total polyphenols) daily for 2 weeks. There were no significant differences in total, LDL, high-density-lipoprotein (HDL), or very-low-density-lipoprotein cholesterol levels or triglycerides at the end of the study period. Lipid peroxides decreased significantly by 6%. Antioxidant activity and serum paraoxonase concentration increased significantly by 9% (p < 0.05) and 18% (p < 0.01), respectively. Three patients were studied for an extended time period of ≤10 weeks and given increasing amounts of pomegranate juice, 20–80 mL daily (equal to 0.54–2.16 mmol total polyphenols). After week 1, lipid peroxide levels decreased by 11% with 20 mL of pomegranate juice daily. The amount of pomegranate juice was increased to 50 mL, which resulted in a 21% decrease in lipid peroxide levels. Pomegranate juice amounts of over 50 mL daily did not result in further changes in lipid peroxide values. Platelet activation was decreased in platelet-rich plasma prepared from 11 volunteers who were given pomegranate juice for 2 weeks, demonstrated by an 11% decrease in collagen-induced platelet aggregation. Limitations of this study included its small sample size, short duration, and lack of a control group. The authors concluded that the antioxidant activity of pomegranate juice may have an important role in atherosclerosis based on its effects on platelets, oxidation, and macrophages.

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Rosenblat et al.^[5] investigated the effects of pomegranate juice on oxidative stress and blood glucose levels. Ten men age 35–71 years with type 2 diabetes mellitus were given 50 mL of pomegranate juice (equal to 1.5 mmol total polyphenols) daily for three months. Antioxidant activity was assessed by measuring serum levels of lipid peroxides, paraoxonase 1, thiobarbituric acid reactive substances (TBARS), and total sulfhydryl groups. Paraoxonase 1 and total sulfhydryl groups exhibit antiatherosclerotic activity; lipid peroxides and TBARS exhibit oxidative activity. Total sulfhydryl groups are also a marker for oxidative stress. Levels of lipid peroxides and TBARS decreased by 56% and 28%, respectively (p < 0.01 for both). Total sulfhydryl groups and paraoxonase 1 levels increased by 12% and 24%, respectively (p < 0.01 for both). C-peptide levels (a product of proinsulin) decreased by 23%. Total cholesterol, LDL cholesterol, glycosylated hemoglobin, and triglycerides were not affected by pomegranate consumption. Insulin and glucose levels improved, but the differences were not significant. The authors concluded that pomegranate juice consumption did not worsen diabetes mellitus and exhibited antioxidant effects, which may attenuate atherosclerosis development; however, the applicability of these results is limited, because the study involved a small number of patients, was conducted for only three months, and involved surrogate markers.

Heber et al.^[6] evaluated the safety and efficacy of a pomegranate supplement in two studies. Patients were given a standardized, commercially available preparation, POMx (POM Wonderful, Los Angeles, CA), which is a pomegranate extract prepared from partially juice-pressed whole fruit and seeds (containing at least 90% polyphenols). All patients were overweight (body mass index of 25–32 kg/m²), with a waist circumference of ≥35 inches for women or ≥40 inches for men, and treated for four weeks. In study 1, 64 patients age 35–65 years were given 710 mg of POMx, 1420 mg of POMx, or placebo daily in a capsule. Complete blood counts, blood chemistry values, urinalysis results, and vital signs were checked at three separate visits. There were no significant changes in laboratory values. No major adverse effects or allergic reactions were reported; however, 9 patients experienced minor adverse effects that the authors believed were unrelated to the pomegranate supplement. In study 2, 22 patients age 40–70 years were given two POMx capsules providing a total daily dose of 1000 mg of pomegranate. The mean ± S.D. TBARS concentration decreased by 0.13 ± 0.23 μM after POMx supplementation (p = 0.044). All other laboratory values remained unchanged; however, there was a significant increase in mean ± S.D. weight (1.30 ± 1.95 pounds, p = 0.005) that the authors believed was more likely a result of holiday-related eating than of the use of the pomegranate supplement. The main limitation of both studies was the short duration (four weeks), and the results may be specific to the POMx supplement used. The authors concluded that POMx was safe and effective when taken for 28 days.

In a randomized study by Guo et al.,^[7] 26 healthy Chinese patients over age 60 years were divided into two groups to receive apple or pomegranate juice. Apples are low in antioxidants, while pomegranates are high in antioxidants. Each patient consumed 250 mL of the assigned juice (the apple juice was a commercially available brand, whereas the pomegranate juice was a freshly squeezed preparation) daily for four weeks. Ferric-reducing antioxidant power (FRAP, which demonstrates antioxidant capacity), glutathione, ascorbic acid, and vitamin E levels were measured. The pomegranate juice group had a greater increase in the mean ± S.D. FRAP (1.46 ± 0.26 mmol/L) compared with the apple juice group (1.36 ± 0.14 mmol/L). There was no difference in glutathione, ascorbic acid, or vitamin E levels between groups. Limitations of this study included its short duration and small sample size. The authors concluded that daily pomegranate juice consumption was associated with significantly better antioxidant activity compared with apple juice consumption.

Am J Health Syst Pharm. 2011;68(14):1302-1305. © 2011 American Society of Health-System Pharmacists, Inc.

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Cite this: Antioxidant and Antiatherogenic Effects of Pomegranate - Medscape - Jul 15, 2011.