The pomegranate (Punica granatum L.), belonging to Punica L. genus, Punicaceae family, is an ancient fruit native to Central Asia in regions spanning from Iran and Turkmenistan to northern India as well as in the Mediterranean area and the Middle East. Pomegranate and its components have been shown in studies conducted over the last several decades to have potent anti-oxidative and anti-inflammatory capabilities. In addition to in vivo and in vitro studies showed that pomegranate exhibits anti-hypertensive and anti-proliferative properties .
Pomegranate fruit is abundant in flavonoids, proanthocyanidins, and natural polyphenols. It is frequently used as nutritional food, for medicinal purposes, health promotion, and strong anti-oxidant action. As pomegranate seeds include vitamin C, vitamin K, folic acid, and bioactive chemicals rich in polyphenols, they have been shown to scavenge reactive oxygen species (ROS). Furthermore, the pomegranate fruit peel was estimated to primarily contain 25 – 28% of the polyphenols with gallic acid and tannins for scavenging ROS, while the pomegranate fruit pericarp mainly contains potent bioactive compounds, such as gallagic, ellagic acid, ellagitannins, punicalagin, anthocyanins delphinidin, pelargonidin, and luteolin .
The Benefits of Pomegranate Extract
The presence of hydrolyzable tannins (ellagitannins and gallotannins), pomegranate derivative ellagic acid, or their common metabolites urolithins was hypothesized to be the reason for the protective benefits .
In hypertensive patients, daily consumption of pomegranate juice for 2 weeks reduced the activity of angiotensin-converting enzyme (ACE) by 36% as well as diminished systolic blood pressure by 5%. The group also reported that patients with carotid artery stenosis significantly decreased their blood pressure, low-density lipoprotein (LDL) oxidation, and common carotid intima-media thickness by consuming pomegranate juice over 3 years. In a cohort of 51 healthy women, pomegranate juice drinking for four weeks significantly lowered blood pressure (without significantly changing serum ACE activity). A subsequent study involving 21 hypertensive patients revealed that pomegranate juice consumption effectively lowered both systolic and diastolic blood pressure .
Consuming pomegranates has a generally positive effect on patients with chronic inflammatory disorders. In patients with hypertension or metabolic syndrome, as well as those undergoing dialysis, pomegranate juice appears to offer promising hypotensive properties. It also resulted in a slight amelioration of lipid profiles in patients with cardiovascular disease (CVD), as pomegranate intake elevated endogenous levels of high-density lipoprotein (HDL) cholesterol and reduced triglyceride (TG) levels. However, several studies have been unable to confirm pomegranate’s TG and cholesterol lowering effect. With regards to risk factors for CVD, one dose of 150 mL of pomegranate juice per day did not influence the level of circulating soluble adhesion molecules or indicators of atherosclerosis and subclinical coronary heart disease (CHD) in hypertensive people. Long-term consumption (100 mL per day for a year) or a higher intake of juice (500 mL per day) were both used to demonstrate the beneficial effects of pomegranate on CVD .
Several groups have studied the effects of pomegranate on the prevention and amelioration of atherosclerosis and other CVD symptoms. In a rat model of the metabolic syndrome, de Nigris et al. (2007) found that supplementation with pomegranate juice or pomegranate fruit extract decreased the expression of vascular inflammatory markers and transforming growth factor β-1 (TGFβ-1), and, likewise, elevated endothelial nitric oxide synthase (eNOS) levels. Additionally, Labsi et al. (2016) demonstrated that Swiss albino mice treated intraperitoneally with pomegranate peel extract for two months after the induction of echinococcosis significantly reduced the nitric oxide (NO) and TNF-α levels .
Reactive oxygen species (ROS) are a by-product of the natural metabolism of oxygen in mammalian bodies, and are neutralized by the anti-oxidant system. Increased ROS production due to exposure to toxic chemicals and xenobiotics leads to an imbalance between the production of ROS and their elimination by anti-oxidant systems. The increased ROS attack cell membranes and damage biomolecules such as proteins and DNA .
Natural anti-oxidants found in pomegranates, such as anthocyanins, catechins, quercetin, gallotannins, ellagitannins, ellagic, ferulic, and gallic acid, are abundant and show promise as anti-oxidants. The most prevalent polyphenols in the peel are ellagitannins (punicalagin and its derivatives), which are known for their strong anti-oxidant properties .
Pomegranate is a rich source of polyphenols and several studies have shown the beneficial role of both pomegranate and its bioactives on reducing oxidative stress and lipid peroxidation through the direct neutralization of ROS, upregulating anti-oxidant enzymes, and modulating transcription factors such as nuclear factor κB (NF-κB) or peroxisome proliferator-activated receptor g (PPARg), among others. The primary bioactive components of pomegranate fruit extract that support skin health are ellagic acid and punicalagin, which have anti-oxidant and anti-inflammatory properties as well as the ability to inhibit the tyrosinase enzyme. Additionally, pomegranate extract stimulates type I procollagen synthesis and inhibits MMP-1 (collagenase) production by dermal fibroblasts .
As confirmed by the reduced histopathological damage, the pomegranate-peel extract meaningfully restored the liver markers. This is consistent with the results in, where the authors revealed that pomegranate’s anti-oxidant properties could reduce oxidative-stress-induced liver injury. It has been discovered that pomegranate phenolic compounds contain anti-oxidant and free-radical-scavenging characteristics, and they also considerably enhanced the kidney weight to body weight ratio .
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