Oral green tea catechin metabolites are incorporated into human skin and protect against UV radiation-induced cutaneous inflammation in association with reduced production of pro-inflammatory eicosanoid 12-hydroxyeicosatetraenoic acid

Abstract

Green tea catechins (GTC) reduce UV radiation (UVR)-induced inflammation in experimental models, but human studies are scarce and their cutaneous bioavailability and mechanism of photoprotection are unknown. We aimed to examine oral GTC cutaneous uptake, ability to protect human skin against erythema induced by a UVR dose range and impact on potent cyclo-oxygenase-and lipoxygenase-produced mediators of UVR inflammation, PGE 2 and 12-hydroxyeicosatetraenoic acid (12-HETE), respectively. In an open oral intervention study, sixteen healthy human subjects (phototype I/II) were given low-dose GTC (540 mg) with vitamin C (50 mg) daily for 12 weeks. Preand post-supplementation, the buttock skin was exposed to UVR and the resultant erythema quantified. Skin blister fluid and biopsies were taken from the unexposed and the UVR-exposed skin 24 h after a pro-inflammatory UVR challenge (three minimal erythema doses). Urine, skin tissue and fluid were analysed for catechin content and skin fluid for PGE 2 and 12-HETE by liquid chromatography coupled to tandem MS. A total of fourteen completing subjects were supplement compliant (twelve female, median 42·5 years, range 29-59 years). Benzoic acid levels were increased in skin fluid post-supplementation (P¼0·03), and methylated gallic acid and several intact catechins and hydroxyphenyl-valerolactones were detected in the skin tissue and fluid. AUC analysis for UVR erythema revealed reduced response post-GTC (P¼0·037). Pre-supplementation, PGE 2 and 12-HETE were UVR induced (P¼ 0·003, 0·0001). After GTC, UVR-induced 12-HETE reduced from mean 64 (SD 42) to 41 (SD 32) pg/ml (P¼0·01), while PGE 2 was unaltered. Thus, GTC intake results in the incorporation of catechin metabolites into human skin associated with abrogated UVR-induced 12-HETE; this may contribute to protection against sunburn inflammation and potentially longer-term UVR-mediated damage.Key words: Green tea catechins: Bioavailability: Skin: 12-Hydroxyeicosatetraenoic acid UV radiation (UVR) in sunlight is a key environmental stressor that makes an impact on skin health. Acute effects include sunburn (an inflammatory response), immune suppression and photosensitivity, while repeated exposures lead to photoageing and photocarcinogenesis (1) . Sunburn is characterised clinically by erythema due to vasodilatation and, histologically, a dermal infiltrate of neutrophils and mononuclear cells is observed (2,3) . Activation of cutaneous phospholipase A 2 by UVR is a key part of the inflammatory response, releasing membrane-esterified fatty acids, including arachidonic acid, which is subsequently metabolised by cyclo-oxygenase (COX), lipoxygenase (LOX) and cytochrome P450 isozymes to produce eicosanoids with vasodilatory and chemoattractant properties (4) . Potent pro-inflammatory mediators, PGE 2 and 12-hydroxyeicosatetraenoic acid (12-HETE), are the most abundant eicosanoids at the peak of the sunburn response, correlating with UVR upregulated expression of COX-2 and 12-LOX in human skin (4) .Polyphenols are plant-der...

Inhibitory effect of plant phenolics on fMLP-induced intracellular calcium rise and chemiluminescence of human polymorphonuclear leukocytes and their chemotactic activityin vitro

“…Gallic acid used topically on the skin showed evidence of anti-aging activities when measured by skin elasticity (Manosroi et al, 2011). Oral consumption of green tea catechins resulted in increased concentrations of gallic acid in skin effusions and a reduced skin susceptibility to UV radiation (Rhodes et al, 2013). There is a lack of sufficient data regarding the antioxidant effect attributed to the consumption of catechol and catechin, in addition to phenolic acids such as 3,4-dihydroxyphenylacetic, 3,4-dihydroxyhydrocinnamic, and 4-hydroxybenzoic acid.…”

Antioxidant activity of various extracts of selected gourd vegetables

“…Olive oil phenolics have been found to decrease the cardiovascular mortality (Keys et al 1986;Covas et al 2006). The beneficial effects of polyphenols in skin applications as antiinflammatory agents has been ascribed to the capacity of polyphenols in altering signal transduction and epigenetic regulation of gene expression (Pastore et al 2011;Pastore et al 2012;Rhodes et al 2013). Another indirect way through which polyphenols may exert antioxidative protection is that these bioactive compounds might increase gene transcription of a factor that regulates enzymes involved in the antioxidant function (Na and Surh 2008).…”

A Randomized Controlled Trial of Green Tea Beverages on the in vivo Radical Scavenging Activity in Human Skin

“…In contrast, only 7 substances could be found in skin biopsies, including quercetin and 5-(3′,4′-dihydroxyphenyl)-γ-valerolactone (M6), a ring fission catechin metabolite derived from gut microbiota [31]. Contrary to the results of the previous work of the same group [32], EGCG was not identified in skin biopsies. However, as EGCG is reported to undergo hydrolysis in vivo [33], it is likely to contribute to the antioxidant status of the skin via its hydrolysis product gallic acid and the colonic metabolite M6, which themselves exert antioxidant activity [34,35].…”

“…Similarly, clinical trials examining the photoprotective effect of oral green tea administration have yielded conflicting results [32,36,37,38]. Furthermore, clinical and epidemiological studies investigating the biological effects of orally administered green tea tend to produce inconclusive results in general, regardless of the topic of investigation [39,40].…”