Coumaperine (an amide alkaloid, present in white piper) and its derivatives were synthesized and investigated for their cytotoxicity against L428 and A549 cells and their NF-κB inhibitory activity. It was found that the coumaperine derivatives CP-9 and CP-38 suppress NF-κB subunits p50 and p65 in nuclear fractions by western blot and by NF-κB luciferase reporter gene assay in a dose dependent manner. Confirmation of these results was obtained by confocal microscopy. CP-9, CP-32 and CP-38 also exhibited dose dependent cell cytotoxicity in a L428 cells expressing constitutively active NF-κB and in A549 cells, with an IC50 value of 43.25 μg/ml, 0.39 μg/ml and 16.85 μg/ml respectively against L428 cells and 57.15 μg/ml, 69.1 μg/ml and 63.2 μg/ml respectively against A549 cells. In addition, the coumaperine derivatives show remarkable inhibitory activity on the cancer cell migration assay against A549 lung adenocarcinoma cells at the concentrations of 5 μg/ml, 10 μg/ml, and 5 μg/ml of CP-9, CP-32 and CP-38 respectively. Aromatic substituents and number of olefinic double bond in coumaperine derivatives found to influence the inhibitory activity. In luciferase reporter gene assay, di-olefin conjugated coumaperine derivatives, CP-38, CP-32 and PIP exhibited higher inhibitory activity than their corresponding tri-olefin conjugated coumaperine derivatives, CP-102, CP-146 and PIP-155 respectively. CP-32 with a stronger electron donating group (-N(CH3)2) showed better inhibitory activity in luciferase reporter gene assay and in cell proliferation of L428 cells. Simple coumaperine derivative (CP-9, with no substituent) effectively inhibited A549 cells proliferation and migration than the other coumaperine derivatives. CP-9 and CP-38 diminish significantly the NF-κB subunits (p50 and p65) of L428 cells in nuclear fractions at the dosage of 10 μg/ml and 30 μg/ml respectively. Which clearly shows that CP-9 and CP-38 inactivate the NF-κB pathway in vitro.