In this paper, the optical properties of viburnum extract flavonoids in the visible region of the spectrum were investigated and their use as a potential photosensitizer of singlet oxygen for photodynamic therapy was evaluated. The presence of long-lived excited states in the extract molecules was established by spectral methods and time-resolved spectroscopy methods and the dependences of the absorption capacity and luminescence intensity of the extract molecules on the concentrations of oxygen and ablative nanoparticles of the gold in the reverse micelles of AOT (sodium dioctyl sulfosuccinate) were established. The plasmonic enhancement of the luminescence of the extract molecules and the processes of their complexation with oxygen were also established. Furthermore, the rate constants of the processes of conversion of exciting energy in complexes were determined.
