The aim of this study was to compare the cyto- and genotoxic effects of quercetin, quercetin sodium salt as well as its complexes with nickel (II) and zinc (II) with the use of Escheiichia coli K-12 recA::gfp microbial biosensor strain containing transcriptional fusion between DNA-damage genotoxin-inducible recA promoter involved in the SOS regulon response and fast folding GFP (green fluorescent protein) variant reporter gene - gfpnmt2. Obtained results indicate that recA::gfpmut2 genetic system was a sensitive biosensor to the most of tested chemicals. The complex of quercetin with sodium, nickel and zinc increased (and in some cases modulated) the reactivity of ircA promoter in relation to control sample. The results indicated that E. coli K-12 iecA::gfp mut2 strain could be potentially useful for monitoring of cytotoxic and genotoxic effect of some biological natural compounds, potentially used in anticancer chemoprevention and therapy.