Abstract: In order to develop application of antioxidative peptides from sheep placenta byproduct by enzymolysis in cosmetics,papain was employed for the enzymolysis and DPPH radical scavenging activity of the hydrolysate was used for efficacy evaluation.The hydrolysate by papain was purified sequentially by DA201-C macroporous resin,ultrafiltration and Sephadex G-10 gel filtration.Fractions obtained from purification operations were evaluated.The sheep placenta peptide S12 displays the highest DPPH radical scavenging activity and was selected for further study.The formulas of skin care lotion and cream containing different content of S12 (0-5%) were designed,and the moisturizing and elastic effect of all skin care product samples were evaluated by MC750 skin test instrument.Results show that after continuous using the skin care lotion and cream containing 4% content of S12 for 60 d,the skin cuticula hydration of 15 volunteers increases by 27 and 31 respectively;the transepidermal water loss reduces by 12.0 and 13.2 g/(m²·h) respectively;and the skin elasticity R₂ increases by 38% and 45% respectively.It is concluded that the skin care lotion and cream containing sheep placenta peptide can improve skin moisturizing and increase skin elasticity.

Key words: additive of cosmetics, sheep placenta, enzymolysis, antioxidative peptide, efficacy evaluation