Photoprotective effects of green tea polyphenols

Department of Dermatology, University of Alabama at Birmingham, Birmingham, AL 35294, USA.
Photodermatology Photoimmunology and Photomedicine (Impact Factor: 1.26). 03/2007; 23(1):48-56. DOI: 10.1111/j.1600-0781.2007.00262.x
Source: PubMed


Non-melanoma skin cancer is the most common malignancy in humans and is equivalent to the incidence of malignancies in all other organs combined in the United States. Current methods of prevention depend on sunscreens in humans, efficacy of which is largely undetermined for non-melanoma skin cancers. Green tea polyphenols have the greatest effect with respect to chemoprevention and have been found to be most potent at suppressing the carcinogenic activity of UV radiation. They protect against many of the other damaging effects of UV radiation such as UV-induced sunburn response, UV-induced immunosuppression and photoaging of the skin. They exert their photoprotective effects by various cellular, molecular and biochemical mechanisms in in vitro and in vivo systems. Green tea polyphenols thus have the potential, when used in conjunction with traditional sunscreens, to further protect the skin against the adverse effects of ultraviolet radiation.

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    • "Several recent studies have reported that some natural bee products inhibit tumour cell growth and metastasis and induce apoptosis of cancer cells [8] , suggesting the potential application of these natural compounds (or their active components) as part of an alternative medical treatment of human tumours [7] . When chemo-and radio-therapy are used systemically or over a broad directed tissue area to kill cancerous cells, they also typically harm healthy cells in the process causing undesirable side effects that limit the treatment (duration and/or dose) and effectiveness, or in the worst cases can kill the patient faster than the cancer would have done. "
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    ABSTRACT: Bee products have long been used in traditional medicine. The raw materials, crude extracts and purified active compounds from them have been found to exhibit interesting bioactivities, such as antimicrobial, anti-inflammatory and antioxidant activities. In addition, they have been widely used in the treatment of many immune-related diseases, as well as in recent times in the treatment of tumors. Bee product peptides induce apoptotic cell death in vitro in several transformed (cancer) human cell lines, including those derived from renal, lung, liver, prostate, bladder and lymphoid cancers. These bioactive natural products may, therefore, prove to be useful as part of a novel targeted therapy for some types of cancer, such as prostate and breast cancer. This review summarizes the current knowledge regarding the in vivo and in vitro potential of selective bee products against tumor cells.
    Asian Pacific Journal of Tropical Biomedicine 05/2014; 4(5):337-44. DOI:10.12980/APJTB.4.2014C1262
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    • "Non-melanoma skin cancer has the highest incidence rate among all cancers [1]. In the US alone, more than 1 million cases are diagnosed every year, which is equivalent to the incidence of malignancies in all other organs combined [2]. The phosphoinositide 3-kinase (PI3K) pathway is frequently targeted in the germ line for somatic mutations in many human cancers. "
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    ABSTRACT: Centipedegrass extract (CGE) is mainly composed of maysin and its derivatives, which are recognized internationally as natural compounds. Compared to other flavonoids, maysin has a unique structure in that mannose is bound to the flavonoid backbone. CGE exhibits some biological properties in that it can function as an anti-oxidant, anti-inflammatory, anti-adipogenic, and insecticidal. Whether CGE has other biological functions, such as anti-cancer activity, is unknown. B16F1 (mouse) and SKMEL-5 (human) cells were treated with CGE, and their subsequent survival was determined using MTT assay. We performed a cell cycle analysis using propidium iodide (PI), and detected apoptosis using double staining with annexin V-FITC-PI. In addition, we examined mitochondrial membrane potentials using flow cytometry, as well as signaling mechanisms with an immunoblotting analysis. CGE inhibited skin cancer cell growth by arresting the cell cycle in the G2/M phase, and increased both early and late apoptotic cell populations without affecting normal cells. Furthermore, we observed mitochondrial transmembrane depolarization, increased cytochrome-c release, caspase-3 and caspase-7 activation, and increased poly ADP-ribose polymerase degradation. CGE also downregulated activation of p-AKT, p-glycogen synthase kinase-3beta (GSK-3beta), and p-BAD in a time-dependent manner. LY294002 inhibition of phosphoinositide 3-kinase (PI3K) significantly sensitized skin cancer cells, which led to an increase in CGE-induced apoptosis. CGE controlled skin cancer cell growth by inhibiting the PI3K/AKT/GSK-3beta signaling pathway and activating the effector caspases. This study is the first to demonstrate anti-cancer properties for CGE, and that CGE may be an effective therapeutic agent for treating skin cancer.
    BMC Complementary and Alternative Medicine 12/2013; 13(1):350. DOI:10.1186/1472-6882-13-350 · 2.02 Impact Factor
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    • "The leaves of this plant are immersed in boiling water a process that, for the most part, prevents oxidation and polymerization of the plant's polyphenols. It is these compounds that are thought to be the major chemopreventive mediators (Yusuf et al., 2007). Another tea presenting antioxidant properties and protection against DNA oxidation is mate tea or yerba mate (Ilex paraguariensis). "
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    ABSTRACT: We evaluated the effects green and mate teas on oxidative and DNA damages in rats exposed to ultraviolet radiation. Were utilized 70 adult male Wistar rats that received daily oral or topic green or mate tea treatment during exposed to radiation by seven days. After, animals were killed by decapitation. Thiobarbituric acid-reactive species levels, protein oxidative damage were evaluated in skin and DNA damage in blood. Our results show that the rats exposed to ultraviolet radiation presented DNA damage in blood and increased protein carbonylation and lipid peroxidation in skin. Oral and topic treatment with green tea and mate tea prevented lipid peroxidation, both treatments with mate tea also prevented DNA damage. However, only topic treatment with green tea and mate tea prevented increases in protein carbonylation. Our findings contribute to elucidate the beneficial effects of green tea and mate tea, here in demonstrated by the antioxidant and antigenotoxic properties presented by these teas.
    12/2013; 37(1):195-201. DOI:10.1016/j.etap.2013.11.028
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