58 Address all correspondence to Gulsah Gedik, gulsahgedik@gmail.com A Preliminary Screening Study with Dermal Tea Formulations Against 311 nm Ultraviolet B Radiation GULSAH GEDIK AND TIMUÇIN UĞURLU Pharmaceutical Technology, Trakya University, Faculty of Pharmacy, Edirne, Turkey (G.G.) Pharmaceutical Technology, Marmara University, Faculty of Pharmacy, Istanbul, Turkey (T.U.) Accepted for publication January 9, 2022. Synopsis One potential health benefit of Camellia sinensis extracts on the skin is protection from the detrimental effects of UV radiation. Tea polyphenols both absorb the UV and also alleviate the UV-induced damage in human skin. In this study, we aimed to test the protection of black and green tea gels against UV. The gels were prepared using a carbomer resin and freeze-dried black or green tea extracts. In formulations, total phenolic content, antioxidant activity, and free radical scavenging activity were tested. The sites were irradiated with an artificial narrow band UVB source 30 min after topical application of the formulations on separate regions of the upper back of 21 subjects, Black and green tea gels, and the commercial sunscreen protected the skin of volunteers against the UV erythema. Caffeine gel and carbopol control gels did not provide any protection. Commercial sunscreens can only protect the skin by absorbing or scattering UV radiation. However, tea extracts both absorb the UV radiation and also have the potential to repair the UV damage inside the skin due to their strong antioxidant contents. Tea extracts are safe for humans as well as for aqueous environments without toxicological concerns. INTRODUCTION The tea plant, Camellia sinensis, contains polyphenolic compounds. The majority of health benefits related to this plant are due to the effects of these polyphenols (1). Tea polyphenols, also called catechins, have been reported to regulate inflammatory responses. Studies display tea polyphenols when applied orally or topically, improve destructive skin reactions following ultraviolet (UV) exposure, including erythema and lipid peroxidation (2). Polyphenols are effective radical oxygen species (ROS) scavengers (3) and they are more potent antioxidants than ascorbic acid and α-tocopherol (4). Besides polyphenols, the tea plant also contains caffeine, l-theanine, minerals, trace amounts of vitamins, amino acids, and carbohydrates. The description of polyphenols contained in tea is determined by the level of fermentation to which it has been subjected (5). White tea consists of minimally processed young leaves and green tea minimally processed mature leaves. While oolong tea is semifermented, black tea is completely fermented. Throughout the J. Cosmet. Sci., 73, 58–69 (March/April 2022)

59 PRELIMINARY SCREENING STUDY WITH TEA FORMULATIONS world, approximately 78% of the tea production is black tea and 20% is green tea, while oolong tea and white tea comprise about 2% of total output (6). Green tea polyphenols generally attribute approximately 35% of the dry solids in brewed form. Epicatechin, epicatechin-3-gallate, epigallocatechin (EGC), and epigallocatechin-3-gallate (EGCG) are the four major classes of green tea polyphenols. The most plentiful among these polyphenols is EGCG with a ratio of about 65% (7). It has been widely reported that the main active ingredient in green tea, EGCG, has a well-established performance as an anti-inflammatory and antioxidant (2). It was found to reduce UV-induced DNA damage dose-dependently in fibroblasts and keratinocytes (8). During the fermentation of black tea, from the smaller catechins, polyphenoloxidase elicits the formation of larger molecules such as orange-red colored dimeric theaflavins (TFs), and dark–brown polymeric thearubigins (TRs) (9,10). The major change was reported to be the oxidation and condensation of EGC and EGCG. Thus, the main difference between green tea and black tea solutions, in terms of polyphenols, is the higher concentration of condensed gallocatechin in black tea (9). The black tea extract inhibited UV radiation-induced tyrosine phosphorylation in the mouse skin and also prevented erythema in human skin after UV exposure (11). Although the great majority of studies on the antioxidative and photoprotective effects of tea and its polyphenols are performed with green tea, it has been shown that TFs and TRs in black tea, like green tea catechins, are also effective in the inhibition of lipid peroxidation. Antioxidative activities of black tea and green tea are reported to have similar potencies (12). Previously, we reported that black or green tea extracts protected the skin from direct UV exposure preventing sunburn and erythema on a small group of subjects (13,14). In this trial, we studied with a larger volunteer population and also included an SPF 50 commercial sunscreen along with green and black tea treatment gels. MATERIALS AND METHODS PREPARATION OF TEA EXTRACT The water-soluble fraction of tea was used in this study and 10 g of black and green dry tea leaves (Çaykur, Rize, Turkey) were weighed. In a separate glass vessel, 100 g of deionized water was boiled. Tea samples were added to water, mixed for 20 min with a mechanical stirrer, and cooled to room temperature. Extracts were filtered using filter paper under a vacuum. The infusions were frozen at −18°C before further processing. Using a laboratory freeze-dryer (Alpha 1-2 LD Plus, Martin Christ, Germany) frozen tea samples were lyophilized at −52°C/0.1 mBar. Freeze-dried samples were stored at −18°C for further quality control tests. PREPARATION OF TEA GELS Gels were obtained using a carbomer resin (Carbopol Ultrez 21, Noveon, USA). 100 mL of 0.75% (w/w) carbomer solution were prepared and 3 g freeze-dried black or green tea extract was added to the carbomer dispersion. By monitoring the pH, 18% sodium hydroxide solution was added drop by drop until a viscous gel was obtained at pH 5.5. Acting as a preservative, 1% benzyl alcohol was used. The gels were stored in glass jars at