L. amara is a medicinal plant used as an aphrodisiac. Several studies show it contains a compound with biological activities such as inhibition of cell proliferation, an anticancer mechanism. This study aimed to profile the metabolites and predict their activities against two breast cancer receptors (ERα (3ERT) and HER2 (3PPO)) with an in silico approach. The metabolite profile of a water and 80% ethanol extract was analyzed by UHPLC-Q-Orbitrap-HRMS. We also investigated the radical scavenging activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH). Putative identification of metabolites in L. amara revealed 46 metabolites (4 unknown), which were predominantly quinoline alkaloids. Some of the compounds from glycosides and phenol groups were also identified. The antioxidant capacity test results showed that the 80% ethanol extract had a higher radical scavenging capacity than the aqueous extract. Based on molecular docking results, the highest affinity for the ERα receptor was found in the tested compound tetrahydropapaveroline and exceeded that of the native 4-OHT ligand. For the HER2 receptor, graveolinine had the highest affinity but was still below that of the native lapatinib ligand. Ligand interactions with Leu 387 and Glu 419 on the active site of the ERα receptor and Phe1004 on the HER2 receptor are thought to play an important role in increasing the energy affinity. Overall, all compounds showed higher affinity for HER2 receptors than ERα. According to our findings, molecular docking and UHPLC HRMS can validate the presence of lunamarine and graveoline metabolites in L. amara samples with anticancer action. Copyright © 2024 by Indonesian Journal of Pharmacy (IJP).