In vitro cytotoxicity assessment of imidazolium ionic liquids: biological effects in fish Channel Catfish Ovary (CCO) cell line.

Increasing interest in the application of ionic liquids as green replacement for volatile organic solvents emphasized the need for the evaluation of their toxic effects at different biological systems in order to reduce the risk for human health and environment. To our knowledge, effects of imidazolium ionic liquids on cellular level of fish cell lines have not been studied yet. The cytotoxicity of imidazolium ionic liquids containing different anions and alkyl chain lengths as the substituent at the cation ring towards the fish CCO cell line was determined by WST-1 proliferation assay. Morphological alterations were examined by fluorescent microscopy using acridine orange/ethidium bromide staining and flow cytometry analysis was also performed. The results showed concentration-dependent cytotoxicity of ionic liquids in CCO cells, related to the type of anion and alkyl chain length, while EC50 values showed moderate to high cytotoxicity of tested imidazolium ionic liquids. Distinct morphological changes observed under fluorescence microscope and data obtained by flow cytometry suggest that the toxicity of imidazolium ionic liquids with longer alkyl chains could be related to necrosis. Results presented in here may be helpful for filling existing gaps of knowledge about ionic liquids toxicity and their impact on aquatic environment.

Balance of glucosinolates content under Cd stress in two Brassica species.

We designed a pot experiment to study the changes of growth parameters, accumulation of Cd in cabbage and kale, during a prolonged exposure period with two harvests (after 45 and 75 days of plant growth). Simultaneously, we monitored changes of total S and GSL contents in different plant organs. Both Brassica species showed tolerance to Cd, since no obvious symptoms of metal toxicity were displayed and no significantly reduced plant biomass were recorded. Moreover, a trend of root biomass enhancement was noticed. In general, the Cd concentration in roots was higher than in other organs. Data indicate that the transport system from roots to shoots was already saturated after the first growing period, while root continued to accumulate Cd during the second growing period. Regardless of differences in the GSL content between cabbage and kale, both Brassica species had a similar response to Cd exposure, indicating that the Brassicacea plant family could have unique features for the regulation of GSL content in order to balance the roles of GSLs as defence compounds and as S reservoirs. During the first growing period, GSLs in leaves and root could be more involved in ameliorating S deficiency rather than plant defence. After long-term Cd exposure, we found differences between GSL patterns in leaves and root. Furthermore, we found increased total GSL levels in the stem during whole experiment which indicates that stem could serve as a GSLs storage organ under Cd stress. This paper provides new insight into the possible roles of GSL in Cd stress.

Cytotoxic effects of imidazolium ionic liquids on fish and human cell lines.

Ionic liquids bring a promise of a wide range of "green" applications that could replace conventional volatile solvents. However, before these applications become large-scale, their toxicity needs to be investigated in order to predict the impact on human health and environment. In this study we assessed the cytotoxicity of imidazolium ionic liquids (in the concentrations between 0.1 mmol L-1 and 10 mmol L-1) in the ovarian fish cell line CCO and the human tumour cell line HeLa using the MTT cell viability assay. Our results showed that the most cytotoxic ionic liquid was 1-n-butyl-3-methylimidazolium bis(trifluoro methylsulphonyl)imide, [BMIM][Tf2N], followed by 1-n-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4], 1-n-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], and 1,3-dimethylimidazolium hexafluorophosphate [MMIM][PF6]. Generally, the effects were concentration-dependent. They also depended on the type of anion and the n-alkyl chain length. The comparison between the fish CCO and human HeLa cell lines suggests that CCO cells provide a good biological system for initial toxicity testing of ionic liquids that could replace in vivo bioassays.