Pomegranate, fruit of the gods

The pomegranate contains powerful polyphenol antioxidants which appear to inhibit the development of atherosclerosis, reduce the risk of cardiovascular disease and positively affect hypertension. Pomegranate extract has also exhibited properties likely to help curb the growth of some forms of cancer.

In ancient Greece, pomegranate was synonymous with life and regeneration. In Egypt it was considered the fruit of the gods and regarded as a symbol of fertility because of its round shape and abundance of seeds. Pomegranate branches featured in the decorative pattern of the pillars of Solomon’s temple. Spanish colonists introduced the pomegranate into California in 1769. Its use in medicine dates back more than 3000 years but it is only very recently that its efficacy in preventing a whole range of potentially fatal diseases has been rediscovered.

Potent antioxidant

The antioxidant activity of pomegranate peel extract has been demonstrated in various models. In rats exposed to carbon tetrachloride, pre-treatment with pomegranate extract protected their livers as well as their levels of the antioxidant enzymes catalase, peroxidase and superoxide dismutase, from the effects of this toxic chemical.

Pomegranates contain a wide variety of flavonoids, representing 0.2%-1% of the fruit. They are an important source of anthocyanins, delphinidin glucosides, cyanidin and pelargonidin.

They are particularly rich in ellagitannins and gallotannins which are primarily concentrated in the peel. Hydrolysable tannins, particularly punicalagins and ellagic acid, are responsible for more than 85% of pomegranate’s antioxidant activity. This group of polyphenol antioxidants are known as punicosides.

Beneficial for cardiovascular health

A recent study conducted by the Lipid Research Laboratory in Haifa, Israel, investigated the effects of polyphenol antioxidant supplementation in animals. The scientists observed an association between pomegranate juice and inhibition of LDL-oxidation and delayed development of atherosclerosis. They then looked at the effects of such supplementation on atherosclerosis patients with carotid artery stenosis. Ten subjects were given supplementary pomegranate juice for three years. Results showed that after the first year, the thickness of the carotid intima media – a marker of atherosclerosis progression – had decreased by 30% in the supplemented patients as compared with controls. In addition, the pomegranate juice had significantly reduced serum LDL levels while simultaneously increasing serum antioxidant status by 130%. After one year’s supplementation with pomegranate juice, researchers noted a decrease in systolic blood pressure of 21%.

Another study examined the effects of daily consumption of 50ml of pomegranate juice in patients with hypertension. After two weeks, researchers observed decreases of 5% in systolic blood pressure and 36% in serum activity of angiotensin conversion enzyme (ACE). Reductions in ACE serum activity appear to mitigate atherosclerosis, independent of the effects of hypertension.

In an Iranian study investigating the effects of such supplementation on the lipid profiles of type 2 diabetics with raised blood lipid levels, patients were supplemented with concentrated pomegranate juice for eight weeks. Significant reductions were observed in total cholesterol, LDL-cholesterol, and in ratios of LDL/HDL cholesterol and total/HDL cholesterol. The study’s authors concluded that consumption of concentrated pomegranate juice was able to modify cardiovascular risk factors in patients with raised cholesterol.

Potential benefits for breast cancer

Breast cancer is one of the most common forms of cancer facing women after the menopause. 17-beta-oestradiol, the body’s most powerful oestrogen, plays a key role in the development of cancer, most forms of which are hormone-dependent in their early stages. Polyphenol constituents derived from pomegranate inhibit 7-beta-hydroxysteroid dehydrogenase type 1, the enzyme which converts oestrone, the weak oestrogen, into its more potent metabolite, 17-beta-oestradiol. Strong expression of this enzyme may be an indicator of poor prognosis in women with breast tumours that are oestrogen-receptor positive.

Following on from these results, the researchers hope to conduct a clinical trial to evaluate pomegranate’s preventive and therapeutic applications for breast cancer.

Effect on prostate cancer

In a recent study, pomegranate extract was shown to inhibit cell growth and induce apoptosis in a highly-aggressive human prostate cancer cell line. Extending their investigations, the same research team tested the effects of oral administration of pomegranate extract on mice implanted with prostate cancer cells. They observed significant inhibition of tumour growth in the pomegranate-supplemented mice as well as reduced secretion of PSA (prostate-specific antigen) in the animals’ serum.

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