Résumé : 7-(3'-Hydroxymethyl-3'-methylallyloxy)coumarin, bearing a 3'-hydroxy-3'-methylallyl group as the O-side chain, and lomatiol, a lapachol derivative sharing the same structural feature, were tested for their in vitro growth inhibitory activities on six cancer cell lines using the MTT colorimetric assay, along with the respective 3',3'-dimethylallyl derivatives and unprenylated products used for comparison. Data revealed that lomatiol displayed the strongest growth inhibitory activities in vitro although not as efficient as the parent compound lapachol. The oxidized O-prenylcoumarin recorded better growth inhibitory capacities than the prenylated and unprenylated parent products.