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J. Cosmet. Sci., 61, 133–145 (March/April 2010) 133 Comparison of hydration, tyrosinase resistance, and antioxidant activation in three kinds of pearl powders DONG-ZI SHAO, CHENG-KUN WANG, HANN-JANG HWANG, CHING-HSIA HUNG, and YU-WEN CHEN, Department of Cosmetics Application and Management, Chung Hwa University of Medical Technology, 89 Wenhwa 1st St., Tainan, Taiwan 717 (D.-Z.S., H.-J.H.), E-Chyun Dermatology Clinic, No.70, Sec. 3, Jhonghua E. Rd., East District, Tainan City, Taiwan 701 (C.-K.W.), Department of Physical Therapy, National Cheng Kung University, Tainan, Taiwan (C.-H.H.), and Department of Physical Therapy, China Medical University, Taichung, Taiwan (Y.-W.C.). Accepted for publication August 24, 2009. Synopsis In recent years, people have bred freshwater pearls as a substitute for natural pearls that occur in seawater, and they have also developed water-soluble pearl powder (P-w) and ultra-micro (P-μ) and ultra-nano pearl pow- der (P-n) products. However, neither the scientifi c value of pearl powder, nor the differences in effi ciencies of different pearl powder products is still unknown. In this study, the effectiveness of three kinds of pearl pow- der products in various applications was compared. Tests for transepidermal water loss (TEWL) and evalua- tions of the skin surface hydration of test subjects showed that pearl powder has a satisfactory moisturizing effect on skin and that P-μ has a distinctly stronger moisturizing effect than P-w. The three pearl powder products can also signifi cantly reduce the activation of tyrosinase and free radicals. In tests for reducing power and 1,1-diphenyl-2-picrylhydrazyl (DPPH) for scavenging free radicals, P-n and P-μ showed better perfor- mance than P-w. These results provide a reliable scientifi c basis for the use of pearl powder in beauty treat- ment, resistance to aging, and clinical medical treatment. INTRODUCTION In accordance with volume 46 of the Compendium of Materia Medica by Li Shizhen of the Ming Dynasty (1578 AD), “applying the pearl to the face can make the skin moisturized and glossy…comfort the mind and eliminate the poxes and the toxicity.” In the Encyclo- pedic Dictionary of Chinese Medicine Xie Guan et al. wrote in 1921: “The pearl can pacify people and brighten the eyes if applied to the face, it can make the skin moisturized and glossy.” For more than 2000 years, pearls have been used in China, and their value in beauty treatment and medicine has been often recognized. Since ancient times, the pearl Address all correspondence to Dong-Zi Shao.