Figure 5: Inhibition of UVB-induced iNOS expression and subsequent NO production by SFE-EtOAc in mouse skin. Prior to UVB (200 mJ/cm2) irradiation SFE-EtOAc (3 μg and 10 μg) was topically applied on the back of BALB/c mice for 30 min. Twenty-four hours later, skin samples were excised from the backs of mice. (a) Protein expression of iNOS was determined by western blot analysis using iNOS-specific primary antibody. Actin was detected to verify equal protein loading. (b) The NO levels in serum were assessed by Griess assay as indicated in Section 2. The relative NO production was represented as fold induction in comparison with the vehicle-treated sham control group. Asterisks indicate a significant difference from the value obtained with UVB alone (** ). For sham control and UVB alone-irradiated groups, same amount of vehicle (acetone-loive oil) was topically applied instead of SFE-EtOAc solution.