Abstract:

This study aimed to evaluate the whitening effect and antioxidant activity of isorosmanol, an active ingredient of Rosmarinus officinalis L.. The ultraviolet B （UVB）-induced skin photoaging （SP） mouse model was used as the research object, and then three doses （1, 2, and 4 mg/cm²） of isorosmanol were transdermally applied to the mice. After 8 weeks of treatment, compared with the UVB group, the epidermal water content in the L-isorosmanol group, the M-isorosmanol group, and the H-isorosmanol group increases the epidermal and dermal morphology improve significantly, the MMP-1 mRNA level decreases, the COL1A1 mRNA level increases, the melanin content, tyrosinase activity, TRP-1 and TRP-2 mRNA relative levels decrease, the α-MSH and MC1R protein relative levels decrease, the SOD, CAT, and GSH-Px activities increase, the MDA content decreases, the Nrf2 （nucleus） protein relative level increases, and the Keap1 protein relative level decreases （P<0.05）. In conclusion, in UVB-induced SP mice, isorosmanol exerts a whitening effect by inhibiting the α-MSH/MC1R signaling pathway and exerts antioxidant activity by activating the Nrf2/Keap1 signaling pathway.

Key words: isorosmanol, skin photoaging, whitening, antioxidant, α-MSH/MC1R, Nrf2/Keap1