Naphthoqinones are one of groups of secondary metabolites widespread in nature. The most important higher plant families containing naphthoqinones are Bignoniaceae, Boraginaceae, Droseraceae, Ebenaceae, Juglandaceae, Nepenthaceae and Plumbaginaceae. Naphthoquinones are also products of secondary metabolism of some fungi, lichens and algae. Many investigators have interested in these compounds because of their broadrange biological activities; antibacterial, fungicidal, antiparasitic and insecticidal. In this work, we studied the effects of juglon on hydroponically grown seedlings of L.). Flax plants were exposed to solutions with various concentrations of juglon and the growth and development of pea (Pissum sativum) plants were analyzed. The results showed that juglon significantly affect the morphology and physiology of the pea (Pissum sativum) plants. Moreover, the production of ethylene was increased due to stress conditions.

The introductory part of this thesis is focused on the theoretical analysis of solved problems as examining the toxicity of naphthoquinones plumbagine and juglone, especially with regard to their allelopatic action. The next section is focuses on the plant stress, caused by the action of stress factors leading to their death. There is an experimental protocol and the possibilities of determination the effect of naphthoquinones on the plant model. Experimental section discusses changing growth parameters of the plant samples in different concentrations of the naphthoquinone. There is examined cell viability and changes in the synthesis of the secondary metabolites. Data obtained by using spectrophotometric and microscopic analysis are evaluated with STATISTICA software and statistical significance are plotted.

Sesqiterpene lactones, a group of plant secondary metabolites which include Cnicin from Cnicus benedictus plant, have an anti-proliferative and anti-tumor effect on mammalian cells by activating specific signaling pathways while also generating oxidative stress. These factors combined drive tumor cell apoptosis. A few of these compounds have reached clinical trials and seem to be a promising chemotherapeutics. The focus of this work is to elucidate the effect of cnicin on C-MYC transcription factor and oncoprotein which is overexpressed in majority of tumor tissues, the effect of cnicin on DEAD-box RNAhelicase DDX3 and on the expression levels of several metabolic genes is also studied. Through the use of western blotting, immunodetection and qPCR it was found out, that cnicin is regulating the expression of C-MYC oncoprotein on both transcriptional and translational levels, while also lowering C-MYC protein stability probably through the effect on PIM-2 kinase. Cnicin is not affecting the total amount of DDX3 protein in cells, but it seems it is lowering its degradation rate. The possible transcriptional regulation of DDX3 by cnicin is still not clear and requires further research. With the use of LC-MS quantitative analysis and qPCR, it was found out that cnicin does not affect the metabolism of...

This master´s thesis discusses cytotoxicity of selected naphthoquinones on prostatic cell cultures. The introductory part is dedicated to general characteristic of naphthoquinones with focus on their cytotoxicity, testing of cytotoxicity and mechanisms of cytotoxicity. This part is followed by chapters about cytotoxicity, characteristics and biological activities of selected naphthoquinones; plumbagin and naphthazarin. The last part of this thesis’ theoretical section speaks about fluorescence microscopy and its use in research of naphthoquinones cytotoxicity. The practical part is dedicated to evaluation of cytotoxical tests’ results and to analysation of pictures of cells obtained by fluorescence microscope. At the end of thesis, all finding are summarized and put in the context.