Photochemopreventive Effect of Pomegranate Fruit Extract on UVA-mediated Activation of Cellular Pathways in Normal Human Epidermal Keratinocytes

Bioavailable constituents/metabolites of pomegranate (Punica granatum L) preferentially inhibit COX2 activity ex vivo and IL-1beta-induced PGE2 production in human chondrocytes in vitro

Several recent studies have documented that supplementation with pomegranate fruit extract inhibits inflammatory symptoms in vivo. However, the molecular basis of the observed effects has not been fully revealed. Although previous studies have documented the inhibition of nitric oxide and cyclooxygenase (COX) activity in vitro by plant and fruit extracts added directly into the culture medium but whether concentrations of bioactive compounds sufficient enough to exert such inhibitory effects in vivo can be achieved through oral consumption has not been reported. In the present study we determined the effect of rabbit plasma obtained after ingestion of a polyphenol rich extract of pomegranate fruit (PFE) on COX enzyme activity ex vivo and the IL-1beta-induced production of NO and PGE2 in chondrocytes in vitro. Plasma samples collected before and 2 hr after supplementation with PFE were tested. Plasma samples collected after oral ingestion of PFE were found to inhibit the IL-1beta-induced PGE2 and NO production in chondrocytes. These same plasma samples also inhibited both COX-1 and COX-2 enzyme activity ex vivo but the effect was more pronounced on the enzyme activity of COX-2 enzyme. Taken together these results provide additional evidence of the bioavailability and bioactivity of compounds present in pomegranate fruit after oral ingestion. Furthermore, these studies suggest that PFE-derived bioavailable compounds may exert an anti-inflammatory effect by inhibiting the inflammatory cytokine-induced production of PGE2 and NO in vivo.

Less-known botanical cosmeceuticals

Complementary and alternative medicine (CAM) has become increasingly popular in the United States during the last 10-15 years. The use of oral and topical supplements falls within this framework. Most oral and topical supplements are based on or include several botanical ingredients, many of which have long histories of traditional or folk medicine usage. Several of the available products derived from botanical sources are touted for their dermatologic benefits. The focus in this discussion will be on a select group of botanical compounds that have been used for dermatologic purposes or show promise for such applications, including: rosemary, polypodium leucotomos, propolis, oatmeal, olive oil, grape seed extract, lavender, mushrooms, and coffeeberry. Other more commonly used products of botanical origin, such as arnica, bromelain, caffeine, chamomile, ferulic acid, feverfew, green tea, licorice, pomegranate, and resveratrol, are also briefly considered.

Inhibition of UVB-mediated Oxidative Stress and Markers of Photoaging in Immortalized HaCaT Keratinocytes by Pomegranate Polyphenol Extract POMx

In recent years there has been an increase in use of botanicals with antioxidant properties as skin photoprotective agents. Pomegranate (Punica granatum L.) fruit possesses strong antioxidant and antiinflammatory properties. Recently, we have shown that pomegranate-derived products rich in anthocyanidins and ellagitannins inhibit UVB-mediated activation of nuclear factor kappa B and modulate UVA-mediated cell proliferation pathways in normal human epidermal keratinocytes. In this study, we evaluated the effect of polyphenol-rich pomegranate fruit extract (POMx) on UVB-induced oxidative stress and photoaging in human immortalized HaCaT keratinocytes. Our data show that pretreatment of HaCaT cells with POMx (10-40 microg mL(-1)) inhibited UVB (15-30 mJ cm(-2))-mediated (1) decrease in cell viability, (2) decrease in intracellular glutathione content and (3) increase in lipid peroxidation. Employing immunoblot analysis we found that pretreatment of HaCaT cells with POMx inhibited UVB-induced (1) upregulation of MMP-1, -2, -7 and -9, (2) decrease in TIMP-1, (3) phosphorylation of MAPKs and (iv) phosphorylation of c-jun, whereas no effect was observed on UVB-induced c-fos protein levels. These results suggest that POMx protects HaCaT cells against UVB-induced oxidative stress and markers of photoaging and could be a useful supplement in skin care products.

Oral Consumption of Pomegranate Fruit Extract Inhibits Growth and Progression of Primary Lung Tumors in Mice

To develop novel mechanism-based preventive approaches for lung cancer, we examined the effect of oral consumption of a human achievable dose of pomegranate fruit extract (PFE) on growth, progression, angiogenesis, and signaling pathways in two mouse lung tumor protocols. Benzo(a)pyrene [B(a)P] and N-nitroso-tris-chloroethylurea (NTCU) were used to induce lung tumors, and PFE was given in drinking water to A/J mice. Lung tumor yield was examined on the 84th day and 140 days after B(a)P dosing and 240 days after NTCU treatment. Mice treated with PFE and exposed to B(a)P and NTCU had statistically significant lower lung tumor multiplicities than mice treated with carcinogens only. Tumor reduction was 53.9% and 61.6% in the B(a)P + PFE group at 84 and 140 days, respectively, compared with the B(a)P group. The NTCU + PFE group had 65.9% tumor reduction compared with the NTCU group at 240 days. Immunoblot analysis and immunohistochemistry were used to determine effect on cell survival pathways and markers of cellular proliferation and angiogenesis. PFE treatment caused inhibition of (a) activation of nuclear factor-kappaB and IkappaBalpha kinase, (b) degradation and phosphorylation of IkappaBalpha, (c) phosphorylation of mitogen-activated protein kinases (extracellular signal-regulated kinase 1/2, c-Jun NH(2)-terminal kinase 1/2, and p38), (d) phosphatidylinositol 3-kinase (p85 and p110), (e) phosphorylation of Akt at Thr(308), (f) activation of mammalian target of rapamycin signaling, (g) phosphorylation of c-met, and (h) markers of cell proliferation (Ki-67 and proliferating cell nuclear antigen) and angiogenesis (inducible nitric oxide synthase, CD31, and vascular endothelial growth factor) in lungs of B(a)P- and NTCU-treated mice. Thus, our data show that PFE significantly inhibits lung tumorigenesis in A/J mice and merits investigation as a chemopreventive agent for human lung cancer.

Attenuation of UVA-induced damage to human keratinocytes by silymarin

BACKGROUND

UV radiation from sunlight is a potent environmental risk factor in skin cancer pathogenesis. UVA is the major portion of UV light reaching the earth surface ( approximately 95%) and it is reported to lead to benign and malignant tumor formation. UVA-mediated cellular damage occurs primarily through the release of reactive oxygen species (ROS) and it is responsible for inflammation, immunosuppression, photoaging and photocarcinogenesis.

OBJECTIVE

The aim of our study was to investigate the potency of silymarin, the polyphenol fraction from the seeds of Silybum marianum, to modulate UVA-induced oxidative damage to human keratinocytes.

METHODS

Skin epidermal cell line HaCaT, extensively used for studying the influence of UV radiation, was chosen as an experimental model. Silymarin's effect on UVA-disrupted cell viability, proliferation, mitochondrial function, and intracellular ATP and GSH level was measured. Furthermore, silymarin's potency to reduce UVA-induced ROS generation, membrane lipid peroxidation, caspase-3 activation and DNA damage was monitored.

RESULTS

Treatment of irradiated HaCaT (20 J/cm(2)) with silymarin (0.7-34 mg/l; 4h) resulted in concentration-dependent diminution of UVA-caused oxidative stress on all studied parameters. Silymarin application extensively reduced GSH depletion and ROS production as well as lipid peroxidation in irradiated cells. Formation of UVA-induced DNA single strand breaks and caspase-3 activity was also significantly decreased by silymarin.

CONCLUSION

The results suggest that silymarin may be beneficial in the treatment of UVA-induced skin oxidative injury and inflammation. However, further studies especially whose using human systems are needed to determine efficacy of silymarin in vivo.

Botanical antioxidants in the prevention of photocarcinogenesis and photoaging

Exposure of the skin to ultraviolet (UV) radiation, particularly its UV-B component (280-320 nm), from the sun results in erythema, edema, hyperplasia, hyperpigmentation, sunburn cells, immunosuppression, photoaging, and skin cancer. Amongst these various adverse effects of UV-B radiation, skin cancer and photoaging are of great concern. More recent changes in lifestyle have led to a significant increase in the amount of UV-B radiation people receive leading to a surge in the incidence of skin cancer and photoaging. As these trends are likely to continue in the foreseeable future, the adverse effect of UV-B has become a major human health concern. Therefore, development of novel strategies to reduce the occurrence of skin cancer and delay the process of photoaging are highly desirable goals. One approach to reduce their occurrence is through photochemoprevention, which we define as the use of agents capable of ameliorating the adverse effects of UV-B on the skin. Photochemoprevention via use of botanical antioxidants, present in the common diet of human have gained considerable attention as photochemopreventive agents for human use. Many such agents have also found a place in skin care products. This review will focus on the effects of selected botanical antioxidants in the prevention of photocarcinogenesis and photoaging.