Abstract—: Model phenanthrene seco-alkaloids (seco-glaucine and seco-boldine) obtained in the medium of subcritical water (SBW) from plant aporphine alkaloids have been studied for the first time as antioxidants and inhibitors of acetylcholinesterase (AChE). Antioxidant activities (in vitro) of model aporphine and phenanthrene alkaloids: boldine, seco-boldine, glaucine and seco-glaucine (BD, s-BD, GL and s-GL) were studied in the reaction with a stable free radical DPPH (1,1-diphenyl-2-picrylhydrazyl). In vivo, antioxidant activity was determined in a bioluminescent test system using genetically modified E. coli strains. In the experiments in vitro (DPPH test) and in vivo (biotest), phenanthrene alkaloids s-GL and s-BD demonstrate the higher antioxidant activity than their aporphine precursors GL and BD. The anticholinesterase activity of alkaloids and their phenanthrene seco-isomers was studied (in vitro) using Ellman’s method with minor modifications. The data on the inhibitory activity of the AChE enzyme with aporphine and phenanthrene alkaloids expressed as IC50 values obtained from dose–response curves demonstrate that the inhibitory activity for seco-boldine (IC50 = 0.21 mM) and seco-glaucine (IC50 = 0.04 mM) is higher than for the initial aporphine alkaloids boldine (IC50 = 0.29 mM) and glaucine (IC50 = 0.44 mM), respectively. Thus, it has been shown that phenanthrene alkaloids obtained in SBW exhibit the higher antioxidant activity and the better inhibitory AChE activity than their aporphine precursors. © 2022, Pleiades Publishing, Ltd.