The NF-κB assay was performed according to established protocol (12 (link)). Tested samples were dissolved in dimethyl sulfoxide (DMSO). Nuclear extract from HeLa cells was evaluated using the Transcription Assay System (Pierce Biotechnology, Rockford, IL, USA). The assay was used to evaluate the binding affinity to biotinylated consensus sequence of the NF-κB subunit p65. Luminescence was detected using Fluostar Optima plate reader (BMG Labtech Inc,). Rocaglamide was used as a positive control.