Skin Transparency Improvement Effects of Rice Vitamin E Crude Extract
Author(s): Yuho Yamauchi, Jingxiu Zhou, Shiori Nakagawa, Yoshikazu Uchida, Toshio Nakamura, Takuo Tsuno.
Background: Rice bran contains various active ingredients that have attracted attention as materials for use in health foods and cosmetics. Vitamin E has beneficial antioxidant effects and are used in cosmetics. We have developed a method for producing Rice Vitamin E crude extract (RVE) which contains bioactive ingredients, such as tocopherols, tocotrienols, and plant sterols from the by-product of rice bran oil extraction. In this study, we verified the effectiveness of rice bran ingredients by using cell culture assays and face application tests in humans.
Methods: The expression of cyclooxygenase-2 (COX-2) and endothelin-1 (EDN-1), both of which promote melanogenesis, was analyzed in HaCaT cells with or without RVE treatment. In the face application test, RVEcontaining cream and placebo cream were each applied to half of the face twice a day, and melanin index measurement and VISIA image analysis were performed.
Results: In cell assays, RVE reduced COX-2 and EDN-1 expression levels. In the application test, the melanin index on the RVE treated side significantly decreased over time from the start of the test, and after 12 weeks, it decreased significantly compared to that with the placebo. In addition, the analysis of the visual analog scale (VAS) questionnaire, which evaluates the participant’s perception of the skin condition, indicated improvements in texture and transparency brought on by RVE.
Conclusions: This study indicates that RVE increases skin transparency by reducing the amount of melanin through suppression of COX-2 and EDN-1 production and by improving texture and elasticity.