Natural carboxylic acids are plant-derived compounds that are known to possess biological activity. The aim of this review was to compare the effect of structural differences of the selected carboxylic acids (benzoic acid (BA), cinnamic acid (CinA), p-coumaric acid (p-CA), caffeic acid (CFA), rosmarinic acid (RA), and chicoric acid (ChA)) on the antioxidant, antimicrobial, and cytotoxic activity. The studied compounds were arranged in a logic sequence of increasing number of hydroxyl groups and conjugated bonds in order to investigate the correlations between the structure and bioactivity. A review of the literature revealed that RA exhibited the highest antioxidant activity and this property decreased in the following order: RA > CFA ~ ChA > p-CA > CinA > BA. In the case of antimicrobial properties, structure-activity relationships were not easy to observe as they depended on the microbial strain and the experimental conditions. The highest antimicrobial activity was found for CFA and CinA, while the lowest for RA. Taking into account anti-cancer properties of studied NCA, it seems that the presence of hydroxyl groups had an influence on intermolecular interactions and the cytotoxic potential of the molecules, whereas the carboxyl group participated in the chelation of endogenous transition metal ions.

Curcumin is a natural substance known for ages, exhibiting a multidirectional effect in cancer prevention and adjuvant cancer therapies. The great advantage of using nutraceuticals of vegetable origin in comparison to popular cytostatic drugs is the minimized side effect and reduced toxicity. The targets in oncological therapy are, among others, tyrosine kinases, important mediators of signaling pathways whose impaired expression is observed in many types of cancer. Unfortunately, the hydrophobic nature of the curcumin molecule often limits its bioavailability, which is why many studies focus on the chemical modification of this compound. Current research is aimed at modifying structures that improve the pharmacokinetic parameters of curcumin, e.g. the formation of nanoparticles, complexes with metals or the synthesis of curcumin derivatives with functional substituents that allow tumor targeting. The article is a review and analysis of current literature on the properties of curcumin and its derivatives in the treatment of cancers directed to signaling pathways of tyrosine kinases and confronts the problem of low assimilation of curcumin with potential therapeutic effects.

The CRISPR/Cas9 system, a natural defence system of bacterial organisms, has recently been used to modify genomes of the most important protozoa parasites. Successful genome manipulations with the CRISPR/Cas9 system are changing the present view of genetics in parasitology. The application of this system offers a major chance to overcome the current restriction in culturing, maintaining and analysing protozoan parasites, and allows dynamic analysis of parasite genes functions, leading to a better understanding of pathogenesis. CRISPR/Cas9 system will have a significant influence on the process of developing novel drugs and treatment strategies against protozoa parasites.