Fig. 4. Effects of nootkatol on ultraviolet radiation (UV)-induced matrix metalloproteinase-1 (MMP-1) production.

(A) Treatment with 7.5, 15, 30, 60, 120, and 240 µg/ml nootkatol showed 111.37% ± 2.88%, 91.33% ± 2.74%, 27.24% ± 3.73%, 21.59% ± 0.51%, 21.50% ± 0.75%, and 20.65% ± 0.23% cell viability, respectively (n = 3). (B) MMP-1 level, expressed as % of control, following exposure to UVB irradiation (16 mJ/cm²) alone and with nootkatol pretreatment (7.5 µg/ml, 59.33% ± 1.49%) (mean ± standard error of the mean, n = 3) (****p < 0.0001).