Pomegranate juice protects nitric oxide against oxidative destruction and enhances the biological actions of nitric oxide.
Pomegranate juice (PJ), which is a rich source of potent flavonoid antioxidants, was tested for its capacity to protect nitric oxide (NO) against oxidative destruction and enhance the biological actions of NO. Employing chemiluminescence headspace analysis, PJ was found to be a potent inhibitor of superoxide anion-mediated disappearance of NO. PJ was much more potent than Concord grape juice, blueberry juice, red wine, ascorbic acid, and DL-alpha-tocopherol. As little as 3 microl of a 6-fold dilution of PJ, in a reaction volume of 5000 microl, produced a marked antioxidant effect, whereas 300 microl of undiluted blueberry juice or nearly 1000 microl of undiluted Concord grape juice were required to produce similar effects. PJ and other antioxidant-containing products were found to augment the anti-proliferative action of NO (DETA/NO) on vascular smooth muscle cell (rat aorta) proliferation. PJ was much more effective than the other products tested and elicited no effects when tested alone in the absence of added NO. Similarly, neither PJ nor the other products enhanced the anti-proliferative action of alpha-difluoromethylornithine, a stable substance that inhibits cell growth by NO-independent mechanisms. In order to determine whether PJ is capable of increasing the production of NO by vascular endothelial cells, PJ was tested for its capacity to upregulate and/or activate endothelial NO synthase (eNOS) in bovine pulmonary artery endothelial cells. PJ elicited no effects on eNOS protein expression or catalytic activity. Moreover, PJ did not enhance promoter activity in the eNOS gene (COS-7 cells transfected with eNOS). These observations indicate that PJ possesses potent antioxidant activity that results in marked protection of NO against oxidative destruction, thereby resulting in augmentation of the biological actions of NO.
Nitric Oxide. 2006 Sep;15(2):93-102
Reactive oxygen species and vascular remodelling in hypertension: still alive.
Reactive oxygen species (ROS) are reactive derivatives of O2 metabolism, including superoxide anion, hydrogen peroxide, hydroxyl radical and nitric oxide. All types of vascular cells produce ROS, primarily via cell membrane-associated NAD(P)H oxidase. Cardiovascular diseases, such as hypertension, are associated with increased ROS formation (oxidative stress). Oxidative excess in the vasculature reduces levels of the vasodilator nitric oxide, causes tissue injury, promotes protein oxidation and DNA damage, and induces proinflammatory responses. ROS are also important intracellular signalling molecules that regulate vascular function by modulating vascular cell contraction/dilation, migration, growth/apoptosis, and extracellular matrix protein turnover, which contribute to vascular remodelling. Interventions to decrease ROS bioavailability regress remodelling and reduce blood pressure in experimental hypertension. Such strategies may have therapeutic potential in cardiovascular diseases.
Can J Cardiol. 2006 Sep;22(11):947-51
Pomegranate juice reduces oxidized low-density lipoprotein downregulation of endothelial nitric oxide synthase in human coronary endothelial cells.
We examined the hypothesis that pomegranate juice (PJ) can revert the potent downregulation of the expression of endothelial nitric-oxide synthase (NOSIII) induced by oxidized low-density liporotein (oxLDL) in human coronary endothelial cells. Western blot and Northern blot analyses showed a significant decrease of NOSIII expression after a 24-h treatment with oxLDL. Accordingly, we observed a significant dose-dependent reduction in nitric oxide bioactivity represented by both basal and bradykinin-stimulated cellular cGMP accumulation. These phenomena were corrected significantly by the concomitant treatment with PJ. Our data suggest that PJ can exert beneficial effects on the evolution of clinical vascular complications, coronary heart disease, and atherogenesis in humans by enhancing the NOSIII bioactivity.
Nitric Oxide. 2006 Nov;15(3):259-63
Effects of a pomegranate fruit extract rich in punicalagin on oxidation-sensitive genes and eNOS activity at sites of perturbed shear stress and atherogenesis.
BACKGROUND: Atherosclerosis is enhanced in arterial segments exposed to disturbed flow. Perturbed shear stress increases the expression of oxidation-sensitive responsive genes (such as ELK-1 and p-CREB). Polyphenolic antioxidants contained in the juice derived from the pomegranate contribute to the reduction of oxidative stress and atherogenesis during disturbed shear stress. AIM OF THE STUDY: To evaluate the effects of intervention with the Pomegranate Fruit Extract (PFE) rich in polyphones (punicalagin, which is a potent antioxidant) on ELK-1, p-CREB, and endothelial nitric oxide synthase (eNOS) expression induced by high shear stress in vitro and in vivo. RESULTS: At the doses used in the study, both the PFE and the regular pomegranate juice concentrate reduced the activation of ELK-1 and p-CREB and increased eNOS expression (which was decreased by perturbed shear stress) in cultured human endothelial cells and in atherosclerosis-prone areas of hypercholesterolemic mice. PFE and pomegranate juice increased cyclic GMP levels while there was no significant effect of both compounds on the conversion of L-arginine to L-citrulline. Administration of these compounds to hypercholesterolemic mice significantly reduced the progression of atherosclerosis and isoprostane levels and increased nitrates. This protective effect was relevant with PFE. Vasomotor reactivity was improved and EC(25) values in response to Ach and NONOate were significantly increased in treated mice in comparison to controls. CONCLUSION: This study indicates that the proatherogenic effects induced by perturbed shear stress can be also reversed by chronic administration of PFE.
Cardiovasc Res. 2007 Jan 15;73(2):414-23
Pomegranate juice sugar fraction reduces macrophage oxidative state, whereas white grape juice sugar fraction increases it.
The antiatherogenic properties of pomegranate juice (PJ) were attributed to its antioxidant potency and to its capacity to decrease macrophage oxidative stress, the hallmark of early atherogeneis. PJ polyphenols and sugar-containing polyphenolic anthocyanins were shown to confer PJ its antioxidant capacity. In the present study, we questioned whether PJ simple or complex sugars contribute to the antioxidative properties of PJ in comparison to white grape juice (WGJ) sugars. Whole PJ decreased cellular peroxide levels in J774A.1 macrophage cell-line by 23% more than PJ polyphenol fraction alone. Thus, we next determined the contribution of the PJ sugar fraction to the decrease in macrophage oxidative state. Increasing concentrations of the PJ sugar fraction resulted in a dose-dependent decrement in macrophage peroxide levels, up to 72%, compared to control cells. On the contrary, incubation of the cells with WGJ sugar fraction at the same concentrations resulted in a dose-dependent increment in peroxide levels by up to 37%. The two sugar fractions from PJ and from WGJ showed opposite effects (antioxidant for PJ and pro-oxidant for WGJ) also in mouse peritoneal macrophages (MPM) from control as well as from streptozotocin-induced diabetic Balb/C mice. PJ sugar consumption by diabetic mice for 10 days resulted in a small but significant decrement in their peritoneal macrophage total peroxide levels and an increment in cellular glutathione content, compared to MPM harvested from control diabetic mice administrated with water. In contrast, WGJ sugar consumption by diabetic mice resulted in a 22% increment in macrophage total peroxide levels and a 45% decrement in cellular glutathione content. Paraoxonase 2 activity in macrophages increases under oxidative stress conditions. Indeed, macrophage paraoxonase 2 activity was decreased after PJ sugars supplementation, but increased after WGJ sugars supplementation. We conclude that PJ sugar fraction, unlike WGJ sugar fraction, decreases macrophage oxidative state under normal and under diabetic conditions. These antioxidant/antiatherogenic effects could be due to the presence of unique complex sugars and/or phenolic sugars in PJ.
Atherosclerosis. 2006 Sep;188(1):68-76
Anti-oxidative effects of pomegranate juice (PJ) consumption by diabetic patients on serum and on macrophages.
Diabetes is associated with increased oxidative stress and atherosclerosis development. In the present study, we investigated the effects of pomegranate juice (PJ; which contains sugars and potent anti-oxidants) consumption by diabetic patients on blood diabetic parameters, and on oxidative stress in their serum and macrophages. Ten healthy subjects (controls) and 10 non-insulin dependent diabetes mellitus (NIDDM) patients who consumed PJ (50ml per day for 3 months) participated in the study. In the patients versus controls serum levels of lipid peroxides and thiobarbituric acid reactive substances (TBARS) were both increased, by 350% and 51%, respectively, whereas serum SH groups content and paraoxonase 1 (PON1) activity, were both decreased (by 23%). PJ consumption did not affect serum glucose, cholesterol and triglyceride levels, but it resulted in a significant reduction in serum lipid peroxides and TBARS levels by 56% and 28%, whereas serum SH groups and PON1 activity significantly increased by 12% and 24%, respectively. In the patients versus controls monocytes-derived macrophages (HMDM), we observed increased level of cellular peroxides (by 36%), and decreased glutathione content (by 64%). PJ consumption significantly reduced cellular peroxides (by 71%), and increased glutathione levels (by 141%) in the patients’ HMDM. The patients’ versus control HMDM took up oxidized LDL (Ox-LDL) at enhanced rate (by 37%) and PJ consumption significantly decreased the extent of Ox-LDL cellular uptake (by 39%). We thus conclude that PJ consumption by diabetic patients did not worsen the diabetic parameters, but rather resulted in anti-oxidative effects on serum and macrophages, which could contribute to attenuation of atherosclerosis development in these patients.
Atherosclerosis. 2006 Aug;187(2):363-71
Pomegranate (Punica granatum) pure chemicals show possible synergistic inhibition of human PC-3 prostate cancer cell invasion across Matrigel.
Four pure chemicals, ellagic acid (E), caffeic acid (C), luteolin (L) and punicic acid (P), all important components of the aqueous compartments or oily compartment of pomegranate fruit (Punica granatum), and each belonging to different representative chemical classes and showing known anticancer activities, were tested as potential inhibitors of in vitro invasion of human PC-3 prostate cancer cells in an assay employing Matrigel artificial membranes. All compounds significantly inhibited invasion when employed individually. When C, P, and L were equally combined at the same gross dosage (4 microg/ml) as when the compounds were tested individually, a supradditive inhibition of invasion was observed, measured by the Kruskal-Wallis non-parametric test.
Invest New Drugs. 2005 Mar;23(2):121-2
In vitro antiproliferative, apoptotic and antioxidant activities of punicalagin, ellagic acid and a total pomegranate tannin extract are enhanced in combination with other polyphenols as found in pomegranate juice.
Pomegranate (Punica granatum L.) fruits are widely consumed as juice (PJ). The potent antioxidant and anti-atherosclerotic activities of PJ are attributed to its polyphenols including punicalagin, the major fruit ellagitannin, and ellagic acid (EA). Punicalagin is the major antioxidant polyphenol ingredient in PJ. Punicalagin, EA, a standardized total pomegranate tannin (TPT) extract and PJ were evaluated for in vitro antiproliferative, apoptotic and antioxidant activities. Punicalagin, EA and TPT were evaluated for antiproliferative activity at 12.5-100 microg/ml on human oral (KB, CAL27), colon (HT-29, HCT116, SW480, SW620) and prostate (RWPE-1, 22Rv1) tumor cells. Punicalagin, EA and TPT were evaluated at 100 microg/ml concentrations for apoptotic effects and at 10 microg/ml concentrations for antioxidant properties. However, to evaluate the synergistic and/or additive contributions from other PJ phytochemicals, PJ was tested at concentrations normalized to deliver equivalent amounts of punicalagin (w/w). Apoptotic effects were evaluated against the HT-29 and HCT116 colon cancer cell lines. Antioxidant effects were evaluated using inhibition of lipid peroxidation and Trolox equivalent antioxidant capacity (TEAC) assays. Pomegranate juice showed greatest antiproliferative activity against all cell lines by inhibiting proliferation from 30% to 100%. At 100 microg/ml, PJ, EA, punicalagin and TPT induced apoptosis in HT-29 colon cells. However, in the HCT116 colon cells, EA, punicalagin and TPT but not PJ induced apoptosis. The trend in antioxidant activity was PJ>TPT>punicalagin>EA. The superior bioactivity of PJ compared to its purified polyphenols illustrated the multifactorial effects and chemical synergy of the action of multiple compounds compared to single purified active ingredients.
J Nutr Biochem. 2005 Jun;16(6):360-7
Pomegranate fruit juice for chemoprevention and chemotherapy of prostate cancer.
Prostate cancer is the most common invasive malignancy and the second leading cause of cancer-related deaths among U.S. males, with a similar trend in many Western countries. One approach to control this malignancy is its prevention through the use of agents present in diet consumed by humans. Pomegranate from the tree Punica granatum possesses strong antioxidant and antiinflammatory properties. We recently showed that pomegranate fruit extract (PFE) possesses remarkable antitumor-promoting effects in mouse skin. In this study, employing human prostate cancer cells, we evaluated the antiproliferative and proapoptotic properties of PFE. PFE (10-100 microg/ml; 48 h) treatment of highly aggressive human prostate cancer PC3 cells resulted in a dose-dependent inhibition of cell growth/cell viability and induction of apoptosis. Immunoblot analysis revealed that PFE treatment of PC3 cells resulted in (i) induction of Bax and Bak (proapoptotic); (ii) down-regulation of Bcl-X(L) and Bcl-2 (antiapoptotic); (iii) induction of WAF1/p21 and KIP1/p27; (iv) a decrease in cyclins D1, D2, and E; and (v) a decrease in cyclin-dependent kinase (cdk) 2, cdk4, and cdk6 expression. These data establish the involvement of the cyclin kinase inhibitor-cyclin-cdk network during the antiproliferative effects of PFE. Oral administration of PFE (0.1% and 0.2%, wt/vol) to athymic nude mice implanted with androgen-sensitive CWR22Rnu1 cells resulted in a significant inhibition in tumor growth concomitant with a significant decrease in serum prostate-specific antigen levels. We suggest that pomegranate juice may have cancer-chemopreventive as well as cancer-chemotherapeutic effects against prostate cancer in humans.
Proc Natl Acad Sci U S A. 2005 Oct 11;102(41):14813-8
Pomegranate juice decreases amyloid load and improves behavior in a mouse model of Alzheimer’s disease.
Although there are no proven ways to delay onset or slow progression of Alzheimer’s disease (AD), studies suggest that diet can affect risk. Pomegranates contain very high levels of antioxidant polyphenolic substances as compared to other fruits and vegetables. Polyphenols have been shown to be neuroprotective in different model systems. We asked whether dietary supplementation with pomegranate juice (PJ) would influence behavior and AD-like pathology in a transgenic mouse model. Transgenic mice (APP(sw)/Tg2576) received either PJ or sugar water control from 6 to 12.5 months of age. PJ-treated mice learned water maze tasks more quickly and swam faster than controls. Mice treated with PJ had significantly less (approximately 50%) accumulation of soluble Abeta42 and amyloid deposition in the hippocampus as compared to control mice. These results suggest that further studies to validate and determine the mechanism of these effects, as well as whether substances in PJ may be useful in AD, should be considered.
Neurobiol Dis. 2006 Dec;24(3):506-15
Photochemopreventive effect of pomegranate fruit extract on UVA-mediated activation of cellular pathways in normal human epidermal keratinocytes.
UVA is the major portion (90-99%) of solar radiation reaching the surface of the earth and has been described to lead to formation of benign and malignant tumors. UVA-mediated cellular damage occurs primarily through the release of reactive oxygen species and is responsible for immunosuppression, photodermatoses, photoaging and photocarcinogenesis. Pomegranate fruit extract (PFE) possesses strong antioxidant and anti-inflammatory properties. Our recent studies have shown that PFE treatment of normal human epidermal keratinocytes (NHEK) inhibits UVB-mediated activation of MAPK and NF-kappaB pathways. Signal transducers and activators of transcription 3 (STAT3), Protein Kinase B/AKT and Map Kinases (MAPKs), which are activated by a variety of factors, modulate cell proliferation, apoptosis and other biological activities. The goal of this study was to determine whether PFE affords protection against UVA-mediated activation of STAT3, AKT and extracellular signal-regulated kinase (ERK1/2). Immunoblot analysis demonstrated that 4 J/cm2 of UVA exposure to NHEK led to an increase in phosphorylation of STAT3 at Tyr705, AKT at Ser473 and ERK1/2. Pretreatment of NHEK with PFE (60-100 microg/mL) for 24 h before exposure to UVA resulted in a dose-dependent inhibition of UVA-mediated phosphorylation of STAT3 at Tyr705, AKT at Ser473 and ERK1/2. mTOR, structurally related to PI3K, is involved in the regulation of p70S6K, which in turn phosphorylates the S6 protein of the 40S ribosomal subunit. We found that UVA radiation of NHEK resulted in the phosphorylation of mTOR at Thr2448 and p70S6K at Thr421/Ser424. PFE pretreatment resulted in a dose-dependent inhibition in the phosphorylation of mTOR at Thr2448 and p70S6K at Thr421/Ser424. Our data further demonstrate that PFE pretreatment of NHEK resulted in significant inhibition of UVA exposure-mediated increases in Ki-67 and PCNA. PFE pretreatment of NHEK was found to increase the cell-cycle arrest induced by UVA in the G1 phase of the cell cycle and the expression of Bax and Bad (proapoptotic proteins), with downregulation of Bcl-X(L) expression (antiapoptotic protein). Our data suggest that PFE is an effective agent for ameliorating UVA-mediated damages by modulating cellular pathways and merits further evaluation as a photochemopreventive agent.
Photochem Photobiol. 2006 Mar-Apr;82(2):398-405
Pomegranate as a cosmeceutical source: pomegranate fractions promote proliferation and procollagen synthesis and inhibit matrix metalloproteinase-1 production in human skin cells.
Pomegranate (Punica granatum) is an ancient fruit with exceptionally rich ethnomedical applications. The peel (pericarp) is well regarded for its astringent properties; the seeds for conferring invulnerability in combat and stimulating beauty and fertility. Here, aqueous fractions prepared from the fruit’s peel and fermented juice and lipophilic fractions prepared from pomegranate seeds were examined for effects on human epidermal keratinocyte and human dermal fibroblast function. Pomegranate seed oil, but not aqueous extracts of fermented juice, peel or seed cake, was shown to stimulate keratinocyte proliferation in monolayer culture. In parallel, a mild thickening of the epidermis (without the loss of ordered differentiation) was observed in skin organ culture. The same pomegranate seed oil that stimulated keratinocyte proliferation was without effect on fibroblast function. In contrast, pomegranate peel extract (and to a lesser extent, both the fermented juice and seed cake extracts) stimulated type I procollagen synthesis and inhibited matrix metalloproteinase-1 (MMP-1; interstitial collagenase) production by dermal fibroblasts, but had no growth-supporting effect on keratinocytes. These results suggest heuristic potential of pomegranate fractions for facilitating skin repair in a polar manner, namely aqueous extracts (especially of pomegranate peel) promoting regeneration of dermis, and pomegranate seed oil promoting regeneration of epidermis.
J Ethnopharmacol. 2006 Feb 20;103(3):311-8