Pomegranate: Benefits, Dosage, Contraindications

Antioxidant

The main antioxidants found in pomegranate are polyphenols: anthocyanins, tannins, and ellagic acid. These substances are powerful inhibitors of LDL (low-density lipoprotein) oxidation and are avid scavengers of reactive oxygen species generated both intra and extracellularly. Pomegranate juice contains about 1.5% by weight flavonoids, polyphenols, pectin, and ascorbic acid. The soluble polyphenol content ranges from 0.2 to 1% and mainly includes anthocyanins. Furthermore, in both in vivo and in vitro studies, extracts from the peel, seeds, flowers, leaves, and pulp also possess antioxidant activities. Notably, the antioxidant activity of pomegranate juice has been compared to that of red wine or green tea, and it appears to be 2 to 3 times superior. In vitro, pomegranate juice has shown beneficial effects on nitric oxide levels probably due to its protective antioxidant effects and enhancement of nitric oxide synthase (NOS) bioactivity. Nitric oxide synthase increases the availability of nitric oxide, an antioxidant and vasodilator.

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Anti-inflammatory

Pomegranate has powerful anti-inflammatory properties, largely mediated by its antioxidant properties. In human research, the anti-inflammatory effects of pomegranate extract have been associated with beneficial changes in the gut microbiome. These effects are likely due to the regulation of inflammatory proteins and the suppression of inflammatory mediators. They include - among other factors - inhibition of cyclooxygenase (COX) activity, lipoxygenase activity, nitric oxide (NO) production, and inhibition of nuclear factor-kappa B (NF-kappaB) transcription factor activity.

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Anticancer

Preliminary clinical research suggests that pomegranate might play a role in preventing certain cancers such as prostate cancer and breast cancer. Pomegranate fruit extracts inhibit cell growth and induce apoptosis of aggressive prostate cancer cells in vitro. Pomegranate fruit extracts also seem to reduce prostate-specific antigen (PSA) levels in animals implanted with prostate cancer cells; and inhibit tumor growth, angiogenesis, and metastasis in animal studies. Polyphenols from fermented pomegranate juice and other pomegranate extracts have activity against malignant breast cancer cells. In vitro and animal studies show that pomegranate constituents can inhibit cell proliferation and metastasis in breast cancer. Pomegranate seed oil also appears to have activity against skin cancer cells. Furthermore, polyphenol fractions from pomegranate exert actions through antiproliferative, apoptotic, antiangiogenic, antioxidant, and possibly anti-inflammatory effects. According to epidemiological research, urolithin glucuronides and ellagic acid present in pomegranate might be responsible for effects against prostate cancer. These studies have also demonstrated that combinations of pomegranate extracts from different parts of the fruit were more effective than a single extract.

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Antimicrobial

The antibacterial and antifungal effects of pomegranate could potentially be protective against infections and inflammation of the mouth, including gingivitis, periodontitis, and dental stomatitis.

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Antiparasitic

Some in vitro and in vivo research suggests that pomegranate extracts have potential antiparasitic activity against adult worms of Schistosoma mansoni. Other in vitro research, but not in vivo, has demonstrated the antiparasitic and antimalarial effects of pomegranate fruit peel, partly by inhibiting plasmepsin-2 (an enzyme that degrades hemoglobin from Plasmodium, parasites that cause malaria).

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Dermatological Effect

Some preliminary research suggests that pomegranate has an anti-aging effect on the skin. An extract from the pomegranate peel may inhibit matrix metalloproteinase-1 (MMP-1, enzymes capable of breaking the peptide bonds of collagen) that destroys collagen in aging skin, and increase procollagen production activity by dermal fibroblasts. Pomegranate seed oil seems to stimulate the proliferation of keratinocytes (cells constituting 90% of the outer layer of the skin and appendages). In vitro, pomegranate extract led to an increase in collagen synthesis and a decrease in MMP-1 expression after UVB treatment of skin fibroblasts. Protective effects against UVA and UVB toxicity have been demonstrated in vitro.

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Cardiovascular

Epidemiological evidence suggests that the cardioprotective properties of fruits such as pomegranate could partly be due to their polyphenol content. In animals, pomegranate fruit decreases marker enzymes of lipid peroxidation. Preliminary clinical evidence suggests that pomegranate could modestly improve cholesterol in some patients. Indeed, pomegranate juice could reduce cholesterol thanks to its polyphenolic components. Additionally, pomegranate leaf contains tannins thought to have anti-hyperlipidemic effects, perhaps by inhibiting pancreatic lipase and decreasing energy intake. Furthermore, a clinical study with pomegranate seed oil demonstrated a beneficial, but limited effect on hyperlipidemic subjects.

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Antifungal

Preliminary clinical research suggests that pomegranate could act as a topical antifungal for the treatment of candida-associated dental stomatitis, though the mechanism of action is not clear. In vitro research shows that pomegranate peel exhibits antifungal activity against two strains of Aspergillus parasiticus, Aspergillus flavus, Aspergillus ochraceus, and Candida albicans. This antifungal activity is believed to be due to a peptide from pomegranate peel. Clinical and in vitro research suggests that pomegranate could be effective against Trichomonas vaginalis (a human parasite responsible for a sexually transmitted infection, most often benign).

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Hypotensive

Researchers studied the effect of consuming pomegranate juice (50mL, 1.5 mmol of total polyphenols per day, for 2 weeks) by hypertensive patients on their blood pressure. A 5% reduction in systolic blood pressure was observed.

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Antiviral

Preliminary research suggests that pomegranate juice might have activity against HIV, influenza virus, and herpes simplex-2 (HSV-2). The polyphenol punicalagin appears to be the active agent against the flu, probably due to its ability to modify viral envelope glycoproteins. Pomegranate extracts rich in polyphenols seem to act synergistically with Tamiflu (prescription antiviral).

Healing

In vivo animal tests have shown the healing properties of extracts from pomegranate bark and flower. An ointment based on methanolic extract of pomegranate skin significantly improved wound contraction and healing period as evidenced by contraction rate, tensile strength, increased synthesis of collagen, DNA, and proteins. These studies were encouraged by the efficacy of the methanolic extract as an antimicrobial and antioxidant.

Fertility effect

In animal research, pomegranate juice increased sperm concentration and motility, spermatogenic cell density, seminiferous tubule diameter and germ cell layer thickness, and decreased the rate of abnormal sperm. Mechanisms of action may include antioxidant effects. Furthermore, some clinical studies suggest that daily consumption of pomegranate juice could improve erectile function in men with atherosclerosis. However, these results could not be confirmed in men suffering from mild to moderate erectile dysfunction.

Neurological

Some animal research shows that pomegranate juice decreases the accumulation of soluble β-amyloid and amyloid deposition in the hippocampus, suggesting a potential role in Alzheimer's disease. For the record, the joint presence of β-amyloid aggregates and tau protein are the hallmarks of Alzheimer's disease. It is suggested that pomegranate bark extract and pomegranate juice may have neuroprotective effects, perhaps due to their hypoglycemic and antioxidant properties.

Antiplatelet/Anticoagulant

Preliminary in vitro research suggests that pomegranate fruit extracts, primarily ellagic acid, could have a potential role in regulating various pathophysiological processes involving thrombin (or thrombin-type proteinase).

Gastroprotective

Animal and in vitro studies suggest that pomegranate and its extracts have gastroprotective effects, most likely due to anti-inflammatory and antioxidant activity. Further animal research shows that pomegranate juice prevents intestinal histopathological changes after infection by Aeromonas hydrophila.a0

Hepato-protective

In an animal model of diabetes and obesity, pomegranate flower extract reduced liver weight, as well as liver triglycerides and lipids.a0