Exploratory study on the effect of ferulic acid derived from rice bran on dull skin

Ferulic acid (FA) from rice bran is known to possess strong antioxidant properties. Furthermore, its multifunctional properties, such as skin whitening, anti-glycation, and anti-inflammatory effects, have attracted attention. We undertook an exploratory study to examine whether FA might be associated with improvements in skin dullness. A single-blind study was conducted on 24 healthy women, in which a cream containing 1% FA was applied to one side of the face and a placebo cream was applied to the other side to verify the effects. To explore the molecular mechanism, RNA-seq was performed on HEKn keratinocyte and Hs68 fibroblast, followed by qRT-PCR. In the human clinical trial, the melanin index significantly decreased in the area where the FA cream was applied, and a questionnaire also subjectively confirmed the improvement of dark and yellowish dullness by FA cream. RNA-seq analysis of HEKn cells treated with FA revealed significant changes in the expression of FGF-2 (basic fibroblast growth factor) promoting melanocyte proliferation, and CD36 (cluster of differentiation 36), related to the removal of advanced glycation end-products (AGEs). qRT-PCR confirmed that FA significantly downregulated FGF-2 and upregulated CD36 expression. These results suggest that FA may exert its effects by regulating the expression of genes involved in melanogenesis and glycation, contributing to the suppression of melanin production and the reduction of AGEs for the improvement of dull skin.