Double-Blinded, Placebo-Controlled Trial of Green Tea Extracts in the Clinical and Histologic Appearance of Photoaging Skin

Department of Dermatology, Emory University, USA.
Dermatologic Surgery (Impact Factor: 2.11). 07/2005; 31(7 Pt 2):855-60; discussion 860. DOI: 10.1111/j.1524-4725.2005.31731
Source: PubMed


Green tea extracts have gained popularity as ingredients in topical skin care preparations to treat aging skin. Green tea polyphenolic compounds have significant antioxidant and anti-inflammatory activities, and studies suggest that these extracts help mediate ultraviolet radiation damage.
To evaluate the effects of a combination regimen of topical and oral green tea supplementation on the clinical and histologic characteristics of photoaging.
Forty women with moderate photoaging were randomized to either a combination regimen of 10% green tea cream and 300 mg twice-daily green tea oral supplementation or a placebo regimen for 8 weeks.
No significant differences in clinical grading were found between the green tea-treated and placebo groups, other than higher subjective scores of irritation in the green tea-treated group. Histologic grading of skin biopsies did show significant improvement in the elastic tissue content of treated specimens (p<.05).
Participants treated with a combination regimen of topical and oral green tea showed histologic improvement in elastic tissue content. Green tea polyphenols have been postulated to protect human skin from the cutaneous signs of photoaging, but clinically significant changes could not be detected. Longer supplementation may be required for clinically observable improvements.

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    ABSTRACT: Tea is the most consumed drink in the world after water. The medicinal value of teahas been historically well known and since ancient times, green tea has been consideredas a healthy beverage. In recent years, green tea's potential health benefits haveextensively been investigated. In the early years, scientists focused their research on themain polyphenolic group present in green tea, catechins, and their anticancer effects.Nowadays the health benefits of green tea catechins (GTC) are increasingly beingexplored against uprising diseases such as diabetes, metabolic syndrome andcardiovascular diseases.Epidemiological studies have indicated metabolic health benefitsfrom regular consumption of green tea. Furthermore, cell and animal studies haveprovided data on the role of GTC in the regulation of glucose uptake from cells, insulinsensitivity or even regulation of beta cells function. Therefore, GTC health benefits led tothe conclusion that green tea can be considered as a beverage with functionalproperties.However, although all the evidence from research on green tea are verypromising, future studies are necessary to fully understand its contribution to humanhealth.The aim of this chapter is to summarize the latest research (cell, animal, humanand epidemiological studies) on the effects of GTC (epigallocatechin-gallate,epigallocatechin, epicatechin-gallate and epicatechin) against conditions accompanying diabetes pathology such as reduced glucose uptake, insulin resistance and beta cellsfunction.
    Green Tea: Varieties, Production and Health Benefits, Edited by Wenbiao Wu, 01/2013: chapter 6. Antidiabetic Propertiew of Green Tea Catechins: pages 109-124; NOVA Publishers., ISBN: 978-1-62257-562-6
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    • "Sunscreen formulated with 2–5% green tea extract has been reported to protect UV irradiation induced photoaging, photoimmunosuppression, cutaneous erythema, thickening of the epidermis, overexpression of CK5/6, CK16, MMP-2, MMP-9, etc. (Li et al. 2009). A double-blind, placebo-controlled trial have been executed with moderate photoaging treated with either a combination regimen of 10% green tea cream and 300 mg twice-daily green tea oral supplementation or a placebo regimen for 8 weeks to monitor the clinical and histologic appearance of photoaging skin (Chiu et al. 2005). It has been found that patients treated with a combination regimen of topical as well as oral showed histological improvement in tissue elastic content, but clinically significant changes have not been observed and it may require longer supplementation for clinically observable improvements. "
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    ABSTRACT: Skin aging involves degradation of extracellular matrix (ECM) in both the epidermal and dermal layers, it leaves visible signs on the surface of skin and the physical properties of the skin are modified. Chronological aging is due to passage of time, whereas premature aging occurred due to some environmental factors on skin produces visible signs such as irregular dryness, dark/light pigmentation, sallowness, severe atrophy, telangiectases, premalignant lesions, laxity, leathery appearance and deep wrinkling. There are several synthetic skincare cosmetics existing in the market to treat premature aging and the most common adverse reactions of those include allergic contact dermatitis, irritant contact dermatitis, phototoxic and photo-allergic reactions. Recent trends in anti-aging research projected the use of natural products derived from ancient era after scientific validation. Ample varieties of phytomolecules such as aloin, ginsenoside, curcumin, epicatechin, asiaticoside, ziyuglycoside I, magnolol, gallic acid, hydroxychavicol, hydroxycinnamic acids, hydroxybenzoic acids, etc. scavenges free radicals from skin cells, prevent trans-epidermal water loss, include a sun protection factor (SPF) of 15 or higher contribute to protect skin from wrinkles, leading to glowing and healthy younger skin. Present era of treating aging skin has become technologically more invasive; but herbal products including botanicals are still relevant and combining them with molecular techniques outlined throughout this review will help to maximize the results and maintain the desired anti-skin aging benefits.
    Phytomedicine: international journal of phytotherapy and phytopharmacology 11/2011; 19(1):64-73. DOI:10.1016/j.phymed.2011.10.003 · 3.13 Impact Factor
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    • "A separate clinical study found that daily oral administration of either 400 or 800 mg of EGCG did not protect against UV-induced erythema (Chow et al., 2003). Similarly, a recent clinical study examined the ability of either topical or oral administration of green tea extract products to reduce the appearance of photoaging skin (Chiu et al., 2005). Forty women with moderate photoaging were randomized and treated with either topical or oral green tea extracts over an eight-week period. "
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    ABSTRACT: The compound (-)-epigallocatechin-3-gallate (EGCG) is the major catechin found in green tea [Camellia sinensis L. Ktze. (Theaceae)]. This polyphenolic compound and several related catechins are believed to be responsible for the health benefits associated with the consumption of green tea. The potential health benefits ascribed to green tea and EGCG include antioxidant effects, cancer chemoprevention, improving cardiovascular health, enhancing weight loss, protecting the skin from the damage caused by ionizing radiation, and others. The compound EGCG has been shown to regulate dozens of disease-specific molecular targets. Many of these molecular targets are only affected by concentrations of EGCG that are far above the levels achieved by either drinking green tea or consuming moderate doses of green tea extract-based dietary supplements. In spite of this, well-designed double-blinded controlled clinical studies have recently demonstrated the efficacy of green tea extracts and purified EGCG products in patients. Therefore, this review highlights results from what the authors believe to be some of the most clinically significant recent studies and describes current developments in the stereoselective total synthesis of EGCG.
    Phytochemistry 10/2006; 67(17):1849-55. DOI:10.1016/j.phytochem.2006.06.020 · 2.55 Impact Factor
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