A new depside, jaboticabin (1), together with 17 known compounds were isolated from the fruit of jaboticaba (Myrciaria cauliflora). The structure of 1 was elucidated by spectroscopic data interpretation. Known compounds were identified by comparison of their spectroscopic data with literature values or by comparison to authentic standards. Compound 1 and the related depside 2-O-(3,4-dihydroxybenzoyl)-2,4,6-trihydroxyphenylacetic acid (2) significantly inhibited chemokine interleukin (IL)-8 production before and after cigarette smoke treatment of cells. Compound 1 was cytotoxic in the HT29 colon cancer cell line (IC50 = 65 microM), and 2 was active against HCT116 colon cancer cells (IC50 = 30 microM). Compounds 1 and 2 also exhibited antiradical activity in the 1,1-diphenyl-2-picrylhydrazyl (DPPH) assay (IC50 = 51.4 and 61.8 microM, respectively). Two anthocyanins, cyanidin 3-glucoside (3) and delphinidin 3-glucoside (4), also showed good activity in these assays.