Abstract:The cytotoxic and protective effects of selected synthetic chalcone analogues have been shown in previous studies. We studied their cytotoxic effect on the modification of mitochondrial membrane potential and on DNA. The first spectral information about the methoxy group as well as the dimethylamino substituent in E-2-arylmethylene-1-benzosuberones molecule was obtained by absorption and emission spectra. The cytotoxic effect of both cyclic chalcone analogues on DNA were detected by alkaline single-cell gel electrophoresis. Better fluorescent chalcone analogue E-2-(4'-dimethylamino-benzylidene)-1-benzosuberone was studied further in fresh isolated mitochondria. The decrease of rat liver mitochondria membrane potential (Δψ) was observed by fluorescence emission spectra. For the collapsing of mitochondrial potentials and as the negative control of mitochondrial function the CCCP uncoupler was used. The absorption maximum of the methoxy group was found at a shorter wavelength (λ = 335 nm) than that of the dimethylamino group (λ = 406 nm). The excitation spectra were very similar to the absorption spectra for both molecules but the emission spectra showed a better fluorescence for dimethylamino derivative. After the addition of E-2-(4'-dimethylamino-benzylidene)-1-benzosuberone to the intact mitochondria the decrease of mitochondrial membrane potential ∆ψ was observed by emisssion fluorescence spectra. Both cyclic chalcone analogues induced DNA damage, which was detected by alkaline comet assay. Mainly the apoptotic cells were detected, but necrotic cells were also present. Similarities in the percentages of DNA migration from the head were observed in both treatment groups. Both benzosuberones, with dimethylamino-and methoxy-substituent, were very active biologically, as shown by DNA results of the comet assay. Due to its better fluorescence properties, only the fluorophore with dimethylamino substituent was selected for further study of the function of rat liver mitochondria. Decline of mitochondrial function as well as mitochondrial DNA damage were evident between experimental and control groups.