Comparison in the protective effects of phenolic compounds isolated from Artemisia argyi (A–N), N-acetylcysteine (NAC, positive control) (O) and artemetin (P) on the iodixanol-induced cytotoxicity in LLC-PK1 cells. Isofraxidin (1), 4,6-dihydroxy-2-methoxyacetophenone (2), methyl 3-(2-hydroxyphenyl)acrylate (3), honokiol (4), 4-hydroxyacetophenone (5), umbelliferone (6), benzoic acid (7), trans-ferulic acid (8), 1H-indole-3-carboxylic acid (9), 4-hydroxybenzoic acid (10), 3-(2-hydroxyphenyl)acrylic acid (11), salicylic acid (12), vanillic acid (13) and methyl caffeate (14). Control cells were treated with the vehicle only (mean ± SD, n = 3, * p < 0.05 compared to the iodixanol-treated group).