Fig. 6.

Luteolin inhibits UVB-induced wrinkle formation and MMP-13 expression in SKH-1 hairless mice. (A) Representative photographs showing anti-photoageing effects of luteolin. Mice were divided into four groups; controls treated with 200 μl acetone and non-irradiated; UVB group, treated with 200 μl acetone and UVB (0.18 J/cm²) irradiated; low dose sample group, treated with 10 μmol luteolin in 200 μl acetone and UVB irradiated; high dose sample group, treated with 40 μmol luteolin in 200 μl acetone and UVB irradiated. (B) Luteolin reduces UVB-induced wrinkle formation. The mice were treated as described for (A), and the extent of wrinkling was graded using a modification of the method proposed by Bissett et al., 32. Data are represented as the mean ±SD (n = 3) (**significant differences at P < 0.01, between the UVB group and sample treated groups). (C) Luteolin inhibits UVB-induced MMP-13 expression. Protein was extracted from mouse dorsal skin as described in the Materials and Methods, and the level of MMP-13 expression was determined by Western blot analysis using specific antibodies against the MMP-13 protein.