j. Cosmet. Sci., 53, 27-34 (January/February 2002) The extract of the flowers of Prunus persica, a new cosmetic ingredient, protects against solar ultraviolet-induced skin damage in vivo YOUNG HA KIM, HE EN YANG, BYUNG KYU PARK, MOON YOUNG HEO, BYOUNG KEE JO, and HYUN PYO KIM, College of Pharmacy, Kangwon National University, Chunchon 200-701 (Y.H.K., H.E.Y., B.K.P., M.Y.H., H.P.K.), and ROD Center, Coreana Cosmetic Co., Cheonan, 333-830 (B. K.J. ), Korea Accepted for publication November 15, 2001. Synopsis The flowers of Prunus persica Batsch have been used for skin disorders in East Asia from ancient times. In this investigation, the ethanol extract from this plant material was prepared and several major constituents were isolated. In addition, the protective effects of the extract were evaluated against solar ultraviolet (UV)-induced skin damage using in vivo animal models of UVB-induced erythema in guinea pigs and ear edema in ICR mice. From the extract, four kaempferol glycoside derivatives were successfully isolated and their contents were measured with HPLC. Among the derivatives isolated, the content of multiflorin B was highest (3.3%, w/w). The P. persica extract clearly inhibited UVB-induced erythema formation dose de- pendently when topically applied (IC5o = 0.5 mg/cm2). It also inhibited UVB-induced ear edema (49% inhibition at 3.0 rag/ear). Moreover, multiflorin B inhibited UVB-induced erythema formation (80% inhibition at 0.3 mg/cm2), indicating that this compound is one of the active principles of the extract. All these results suggest that P. persica extract may be useful for protection against UVB-induced skin damage when topically applied. INTRODUCTION In order to find plant materials having protective effects on solar ultraviolet (UV)- induced skin damage, various plant extracts were initially screened (1), and the extract of Prunus flowers was selected for further study. Topical application of the flowers of Prunus persica have long been used in Chinese medicine for treating skin disorders (2). Previously, the ethanol extract from the flowers of P. persica (Ku-35) was tested for protective effects against UV-induced damage in keratinocytes and fibroblasts in vitro. Ku-35 significantly inhibited the release of UVB-induced arachidonate acid metabolites Address all correspondence to Hyun Pyo Kim. 27

28 JOURNAL OF COSMETIC SCIENCE from normal human keratinocytes (3). Ku-35 also potently inhibited UV-induced DNA breakage from skin fibroblasts, measured by the single cell gel electrophoresis assay (4). These previous findings strongly suggest that Ku-35 may give protection from UV- induced skin damage such as erythema, premature aging, wrinkle formation, and ulti- mately skin cancer, when topically applied. To check this possibility, Ku-35 was evalu- ated in this investigation for its inhibitory activity against i, vivo animal models of UVB-induced erythema and edema formation. From the results, it was found, for the first time, that topical application of Ku-35 significantly inhibits the formation of UVB-induced erythema as well as edema. In addition, four flavonoid constituents (com- pounds I-IV) were isolated from this plant material and structurally identified as kaempferol 3-O-[IB-D-glucopyranosyl(1 •4)-o•-L-rhamnopyranoside], kaempferol 3-O- IB-D-galactopyranoside, kaempferol 3-O-o•-L-rhamnopyranoside, and kaempferol 3-0- IB-D-glucopyranoside, and their contents were measured using HPLC separation tech- niques. MATERIALS AND METHODS MATERIALS AND APPARATUS SH- and S3C-NMR were measured in JEOL 200 MHz NMR using an internal standard. Melting points were measured with the Fisher-Johns melting point apparatus and were uncorrected. Silica gel (70-230 mesh), TLC plates (F254) , and a lobar column (RP-18) were from Merck (Germany). PLANT MATERIAL The flowers ofP. persica (Rosaceae) were collected in several orchards located in Kangwon province (Korea) in April 1997 and 1998, and dried in the dark. A brochure specimen was deposited at the College of Pharmacy, Kangwon National University. ANIMALS Male Hartly guinea pigs and male ICR mice were purchased from Charles River Labo- ratories (Japan). The animals were maintained in the SPF animal facility at KNU under conditions of 20ø-22øC, 40-60% relative humidity, and a 12 hr/12 hr (L/D) cycle. UVB SOURCE For irradiation on animals, the strength of a UVB lamp (Model XX-15B, medium wavelength [312 nm], Spectroline, Westbury, NY) was adjusted using a DRC-100X digital radiometer (Spectroline) as described previously (3). PREPARATION OF THE EXTRACT AND ISOLATION OF KAEMPFEROL GLYCOSIDES The dried flowers ofP. persica were extracted with 80% aqueous ethanol according to the previous report (3). The extract (Ku-35) was filtered and dried i, vac•o. For i, vivo study,