THE WHITENING AND ANTI-WRINKLE EFFECT OF PONEGRANATE 155 inhibited tyrosinase activation, whereas melanin formation was signifi cantly inhibited by 0.01% and 0.05% PCS. These results suggest that PCS may affect skin whitening. Immortalized mouse melanocytes, Melan-a cells, were derived from normal epidermal melanoblasts from embryos of inbred C57BL mice. Thus, Melan-a cell line was used to evaluate the effects of skin whitening. Melanin is produced in melanocytes and Figure 5. Representative histological images of dorsal back skin tissues taken from unexposed intact or UVB-exposed hairless mice. (A) Normal, nonirradiated vehicle control hairless mice (intact control). (B) UVB-irradiated vehicle control hairless mice (UVB control). (C) UVB-irradiated and PCS-administrated hairless mice (PCS-0.5). (D) UVB-irradiated and PCS-treated hairless mice (PCS-1). (E) UVB-irradiated and PCS-administrated hairless mice (PCS-2). (F) Normal, nonirradiated and PCS-administrated hairless mice (intact PCS-1). Arrows indicate microfolds formed. All tissues were stained with H&E. Scale bar = 50 μm.

Table I General Histomorphometrical Analysis on Dorsal Back Skin Tissue Following UVB Irradiation and Treatment with PCS Group index Control Test materials (PCS) Intact PCS Intact UVB 0.5 ml/kg 1 m1/kg 2 m1/kg 1 m1/kg Microfolds (number/mm of skin) 11.44 ± 4.42 63.89 ± 13.83 a 46.11 ± 9.92 a, b 37.00 ± 10.07 a, c 41.00 ± 12.21c a, 11.22 ± 3.53d, e Epithelial thickness (μm) 19.73 ± 2.77 73.36 ± 10.89 a 59.93 ± 10.64b a, 42.05 ± 11.92 a, c 49.43 ± 13.58c a, 19.15 ± 2.46e Infl ammatory cells (cells/mm2 of dermis) 11.78 ± 5.67 220.89 ± 26.85 a 173.78 ± 24.63c a, 98.78 ± 36.01 a, c 112.44 ± 45.26c a, 11.22 ± 5.43e Collagen fi bers (%/mm2of dermis) 52.48 ± 6.50 84.27 ± 6.05d 74.13 ± 8.29 a, e 66.80 ± 11.56d, f 70.29 ± 12.41 d, f 50.90 ± 7.21b Values are expressed as the means ± S.D. from nine histological fi elds of dorsal back skin tissues. a p 0.01 as compared with intact control by MW test. b p 0.05 as compared with UVB control by MW test. c p 0.01 as compared with UVB control by MW test. d p 0.01 as compared with the intact control by LSD test. e p 0.05 as compared with UVB control by LSD test. f p 0.01 as compared with UVB control by LSD test. JOURNAL OF COSMETIC SCIENCE 156