Chitin, the second most important natural polymer in the world, and its N-deacetylated derivative chitosan, have been identified as versatile biopolymers for a broad range of applications in medicine, agriculture and the food industry. Two of the main reasons for this are firstly the unique chemical, physicochemical and biological properties of chitin and chitosan, and secondly the unlimited supply of raw materials for their production. These polymers exhibit widely differing physicochemical properties depending on the chitin source and the conditions of chitosan production. The presence of reactive functional groups as well as the polysaccharide nature of these biopolymers enables them to undergo diverse chemical modifications. A complete chemical and physicochemical characterization of chitin, chitosan and their derivatives is not possible without using spectroscopic techniques. This review focuses on the application of spectroscopic methods for the structural analysis of these compounds.

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Altered metabolism of lipids is currently considered a hallmark characteristic of many malignancies, including colorectal cancer (CRC). Lipids are a large group of metabolites that differ in terms of their fatty acid composition. This review summarizes recent evidence, documenting many alterations in the content and composition of fatty acids, polar lipids, oxylipins and triacylglycerols in CRC patients’ sera, tumor tissues and adipose tissue. Some of altered lipid molecules may be potential biomarkers of CRC risk, development and progression. Owing to a significant role of many lipids in cancer cell metabolism, some of lipid metabolism pathways may also constitute specific targets for anti-CRC therapy.

This paper presents cytotoxicity data of selected imidazolium ionic liquids evaluated in vitro on the human tumor cell line HeLa. It was found that for 1-n-butyl-3-methylimidazolium entities the toxicity depends strongly on the associated anion; EC50 values are lowest for tetrafluoroborate. No direct dependence of the reduced effect concentration was found on elongating the short, methyl chain to ethyl or n-hexyl. Only for the ionic liquid with an n-decyl chain, the longest one studied, did higher hydrophobicity result in a EC50 one order of magnitude lower than that obtained with the n-butyl entity. The effect concentrations of imidazolium ionic liquids in the HeLa system used are lower than the values obtained for conventional organic solvents such as dichloromethane, toluene or xylene.

Motivated by the prevailing need for a sustainable development and taking the principles of Green Chemistry as a starting point, the present paper describes new and updated findings regarding a sustainable product design for ionic liquids. The focus is on environmental risk. Nevertheless, cytotoxicity testing and first indicative results from a genotoxicity study extend present knowledge also with regard to possible effects on humans. The structural variability of commercially available ionic liquids as well as the abundance of theoretically accessible ionic liquids is illustrated and the consequences for an integrated risk assessment accompanying the development process are discussed. The side chain effect on toxicity for imidazolium type ionic liquids was confounded by more complex biological testing. Also, an influence of an anion on cytotoxicity is shown for the first time. Testing of presumed metabolites of the imidazolium type cations showed a significantly lower biological activity in cytotoxicity studies than their parent compounds. The importance of a purity assessment for ionic liquids is pointed out and a collection of methods that is believed to be adequate is presented. In addition to risk analysis, the use of life cycle analysis for the multi-objective problem of designing ionic liquids is sketched and an eco-design scheme for ionic liquids is proposed. In conclusion, the paper illustrates the complex nature of the development processes ionic liquids are currently undergoing and provides guidance on which aspects have to be kept in mind.