Fermented rice bran extract delays skin aging by increasing the synthesis of collagen and elastin

Xin Yan¹qing Mei Yang²yi Xu Cai³wei Yi Shen⁴han Rui Jiang²Rizhong Huang²Huaikai Shi⁵Gregory Cheng⁶wei Yi Wang²Qian Tan^1*Yuen Yee Cheng^7*Nannan Xue^8*

• ¹Nanjing University Medical School Affiliated Nanjing Drum Tower Hospital, Nanjing, China
• ²Nanjing University of Chinese Medicine, Nanjing, China
• ³China Pharmaceutical University, Nanjing, China
• ⁴Beijing University of Chinese Medicine, Beijing, China
• ⁵NSW Dust Diseases Board, Sydney, Australia
• ⁶Synertechcare Australia Pty Ltd, Riverwood, NSW, Australia, sydney, Australia
• ⁷University of Technology Sydney, Sydney, Australia
• ⁸Department of Human Anatomy and Histoembryology, School of Medicine and Life sciences, Nanjing University of Chinese Medicine, Nanjing, China

Background: Rice bran, the outer layer of rice grains (Oryza sativa). Due to its rich bioactive components, it has long been used in cosmetics. However, the mechanism by which it delays skin aging remains unclear. Methods: In this study, volatile polar solvents combined with microbial fermentation were utilized to enhance the yield and bioavailability of functional components in rice bran extract. The crude rice bran extract was fermented with Aspergillus oryzae for 14 days to promote enzymatic decomposition into smaller and more bioavailable molecules. The components in the fermented rice bran extract were qualitatively analyzed by UPLC-QTOF-MS/MS. The expression of collagen in two-dimensional and three-dimensional cell cultures was evaluated by qPCR technology. The expressions of collagen and elastin, as well as the changes in water content and elastic modulus in the skin of mice were evaluated by histopathology, immunofluorescence staining and Transepidermal water loss (TEWL). Results: Through UPLC-QTOF-MS / MS analysis, eight key compounds including Azelaic acid, Ferulic Acid, γ-Tocotrienols, Squalene, etc. were identified in RBE, mainly lipids and polyphenols. The treatment of RBE significantly up-regulated the expression of type I collagen in MSF cells and the expression of type III collagen in MSF3D cell spheres (about 12 times). The results of tissue staining and immunofluorescence staining showed that the content of collagen in the skin increased by about 10 % and the content of elastin increased by 1 time after RBE treatment. The TEWL results showed that the skin moisture content and elastic coefficient of mice treated with RBE increased by more than 10% compared with the untreated group. Conclusion: Both in vitro and in vivo studies have shown that RBE can significantly improve the synthesis of collagen and elastin in the skin, reduce water loss in mouse skin, increase collagen deposition in the skin, and ultimately improve skin elasticity and overall quality. This green, solvent-efficient and fermentation-enhanced approach offers a sustainable strategy for utilizing rice bran as a high-value cosmetic ingredient with strong potential for skin care applications.