Phytochemicals and antibacterial and antioxidant activities of Cadia purpurea roots were investigated herein for the first time. The phytochemical study led to the isolation of two compounds, di-(2-methylheptyl) phthalate (1) and 13-O-pyrrolecarboxyl lupanine (2), from methanol roots extract of C. purpurea. The antibacterial activity results revealed that the n-hexane extract presented a better inhibitory value (13.8 +/- 0.0 mm) followed by chloroform (11.1 +/- 0.4 mm) and chloroform : methanol (1 : 1) (10.7 +/- 0.1 mm) extracts against E. coli at the maximum dose of 100 mg/mL. While, methanolic and ethanolic extracts displayed a mild activity against same bacterium at same dose. The methicillin resistant S. aureus was found with almost total resistance to all extracts up to the 100 mg/mL. The chloroform : methanol (1 : 1), chloroform, and n-hexane extracts recorded inhibition zone values (8.0 +/- 0.0-10.0 +/- 0.1 mm, 7.7 +/- 0.0-9.8 +/- 0.1 mm, and 7.3 +/- 0.2-8.9 +/- 0.2 mm, respectively) better than chloramphenicol (7.2 +/- 0.6 mm at 30 mu g dose) against P. aeruginosa. The alcoholic extracts also exhibited an activity better than chloramphenicol up to 25 mg/mL against same bacterium. Compound 2 produced a comparable inhibition value (9.6 +/- 0.0 mm to 18.5 +/- 0.0 mm) to that of chloramphenicol (21.5 +/- 0.3 mm) against E. coli at doses up to 1.0 mg/mL; whereas, compound 1 showed a slight activity (7.1 +/- 0.1 mm-10.3 +/- 0.0 mm). Both compounds were found generally inactive against S. aureus, while they provided an activity better than chloramphenicol (7.2 +/- 0.6 mm) against P. aeruginosa with inhibition zones ranging from 7.1 +/- 0.0 mm to 9.0 +/- 0.1 mm for compound 1 and 7.2 +/- 0.0 mm to 10.6 +/- 0.0 mm for compound 2. Ethanolic and methanolic extracts exhibited a better DPPH radical scavenging activity (IC50 values of 12.9 and 16.03 mu g/mL, respectively) and strong ferric ion reducing power (with absorbance of 0.788 +/- 0.000 and 0.810 +/- 0.001, respectively) at a concentration of 500 mu g/mL compared to the other extracts. Compound 1 also possessed a better anti-DPPH trapping activity (IC50, 7.99 mu g/mL) than compound 2 (IC50, 58.34 mu g/mL). The compounds, however, indicated a weak ferric ion reduction power even at higher amount. In general, the observed antibacterial and antioxidant activities of isolated compounds and extracts were found to be dose-dependent. Conducting further biochemical investigations on all parts of this plant could provide opportunities of finding extra alkaloidal compounds and other phthalate derivatives with better biological activity.