J. Cosmet. Sci., 65, 11–24 (January/February 2014) 11 Preventive effects of tamarind seed coat extract on UVA-induced alterations in human skin fi broblasts KHEMJIRA PHETDEE, RACHARAT RAKCHAI, KWANCHAI RATTANAMANEE, THANASAK TEAKTONG, and JARUPA VIYOCH, Department of Pharmaceutical Technology (K.P., R.R., J.V.), and Department of Pharmacy Practice (K.R., T.T.), Faculty of Pharmaceutical Sciences and Center of Excellence for Innovation in Chemistry, Naresuan University, Phitsanulok 65000, Thailand. Accepted for publication July 30, 2013. Synopsis One of the most damaging actions on skin is from solar radiation, particularly from its ultraviolet (UV) component, through the formation of oxidative species. Thus, an antioxidant strategy that prevents the formation of these oxidants could form the basis of an effi cacious cutaneous protectant. Many herbal mate- rials contain antioxidant polyphenols, and this study assessed the possibility that tamarind seed coat ex- tract could fulfi ll this role. An alcoholic extract of the tamarind (Tamarindus indica L.) seed coat showed stronger antioxidant activity (2,2-diphenyl-1-picrylhydrazyl inhibition, EC50 = 12.9 μg/ml) than L-ascor- bic acid (EC50 = 22.9 μg/ml) and α-tocopherol (EC50 = 29.3 μg/ml). In cultured fi broblasts taken from human skin, hydrogen peroxide (100–1000 μM) damaged 62–92% of the cells compared to only 35–47% when the cells were preincubated in extract (200 μg/ml) for 24 h. UVA (40 J/cm2) irradiation of human fi broblasts damaged 25% of the cells but the death rate was reduced to 10% with extract. UV irradiation increased the proportion of cells arrest in G0/G1 phase (from 59% to 78%) but this was largely prevented by the extract (64%), according to fl ow cytometry. Intracellular total glutathione of UVA-irradiated cells pretreated with the extract increased to 10–25% compared to the non-pretreated group at 24–72 h after irradiation. Fibroblasts typically increased matrix metalloproteinase-1 secretion after photodamage, and this is prevented by the extract. This is the fi rst report showing that tamarind seed coat extract is an anti- oxidant and can protect human skin fi broblasts from cellular damage produced by UVA and thus may form the foundation for an antiaging cosmetic. INTRODUCTION Solar ultraviolet (UV) radiation is composed of UVA (320–400 nm), UVB (280–320 nm), and UVC (100–280 nm) and of these, UVA is able to penetrate the reticular dermis, thereby accelerating skin aging. This infl uences fi broblast functions including in- Address all correspondence to Jarupa Viyoch at jarupav@nu.ac.th or jarupaviyoch4@yahoo.com. Some data from this article were presented as an oral presentation at World Congress of the International Society for Biophysics and Imaging of the Skin (ISBS), held during November 28–30, 2012 at DGI-byen Conference Center, Copenhagen, Denmark.

JOURNAL OF COSMETIC SCIENCE 12 creased matrix metalloproteinase-1 (MMP-1) secretion and decreased type I procolla- gen expression level (1–3). UV exposure causes formation of reactive oxygen species (ROS) that activate the signal transduction pathways involved in MMP-1 and procol- lagen expressions, and also growth, differentiation, senescence, and/or damage of fi bro- blasts (4–6). ROS-induced cell damage correlates with cell-cycle arrest (7–9). Nevertheless, skin possesses extremely effi cient antioxidant defenses such as superoxide dismutases, glutathione peroxidases, glutathione reductase, and catalase. However, ex- cessive exposure to UV can overwhelm the defense and cellular macromolecule repair capacities, leading to an accumulation of oxidative damage to cells. Therefore, exoge- nous antioxidants could moderate the free-radical burden, thereby ameliorating the process of skin aging and damage. Plant phenols and polyphenols constitute an important group of naturally occurring an- tioxidants because the phenolic group can accept electrons from ROS, which benefi ts to cutaneous function. Thus, they promote procollagen production and inhibit metallopro- teinases, hence preventing proteolytic degradation of extracellular matrix (1,10–12). Tamarind (Tamarindus indica L.) grows widely throughout tropical climates and its seed coat is an industrial waste. Its polyphenol content includes catechins, 2-hydroxy-3, 4-dihydroxyacetophenone, methyl 3,4-dihydroxybenzoate and 3,4-dihydroxyphenyl ac- etate, which are antioxidants in vitro (13,14) as well as have additional health benefi ts (13,15,16). Likewise, tamarind seed coat may also protect skin against UV-induced dam- age but such an effect has not yet been identifi ed. Thus, we aimed to show that the tamarind seed coat extract containing phenolic com- pounds could reduce UVA-induced alterations of fi broblast viability and functions. The extract was tested on (i) oxidative damage in fi broblasts created by hydrogen peroxide (H2O2) and (ii) irradiated fi broblasts for cell cycle, and levels of total glutathione, type I procollagen, and MMP-1. The data suggest that tamarind seed coat extract has a UV- protectant action. MATERIALS AND METHODS PREPARATION OF TAMARIND SEED COAT EXTRACT Ripe tamarind seeds were purchased from a local market in Phetchabun Province, Thai- land. The seeds were heated in a hot air oven at 140oC for 45 min, cooled, and cracked to separate the outside brown layer. Only brown-red seed coats were collected and then ground into fi ne powder. For seed coat extraction, 70% ethanol was used. A Sephadex LH-20 (GE Healthcare Bio-Sciences AB, Uppsala, Sweden) column was used to remove tannin, and the extract was dried under vacuum and then stored in a tight Amber glass bottle at 4°C for further studies. QUANTIFICATION OF TOTAL PHENOLIC COMPOUNDS IN THE EXTRACT The amount of total phenolic compounds was determined by Folin–Ciocalteu assay. The Folin–Ciocalteu reagent (Sigma-Aldrich, St. Louis, MO) is a mixture of phosphomolybdate