Comparative in vitro cytotoxicity of active disinfectant substances and a commercially available surface disinfectant on human respiratory epithelial cells

Disinfection of hands and surfaces is a key element in preventing the spread of infections. In this study, the cytotoxic effect of chemical substances used in conventional disinfectants was assessed: n-propyl alcohol (1P), isopropyl alcohol (2P), ethyl alcohol (EtOH), phenoxyethanol (FenEtOH), glutaraldehyde (GA), didecyldimethylammonium chloride (DDAC), sodium diisocyanurate (NaDCC), potassium peroxymonosulfate (KPMS) and the ready-to-use commercially available mixture for surface disinfection Mikrozid AK liquid (MAF). The assessment was performed on two cell lines derived from the human respiratory system: BEAS-2B and A549. To assess the cytotoxic effect of the tested compounds/mixture, the MTT and NRU assays were used. Based on the obtained results, DDAC and GA were found to be the most cytotoxic, while NaDCC and KPMS exhibited slightly lower levels of cytotoxicity. The alcohols: 1P, 2P and EtOH were characterized by lower toxicity on cells of both lines. The commercially available MAF mixture was the least toxic to A549 cells. Moreover, 2P, GA and EtOH exhibited a stronger cytotoxic effect on the metabolic activity of cells assessed by the MTT in both tested respiratory system-derived cell lines, compared to their effect on cell membrane integrity, which was evaluated using the NRU test. The obtained results also indicate that BEAS-2B cells are significantly more sensitive to the cytotoxic effects of the tested compounds than A549 cells, a difference that was particularly evident upon exposure to 1P, GA, DDAC, NaDCC and MAF in both tests.