Plant polysaccharides include pectins, which are responsible for an important role in plant physiology and are part of the plant cell wall. These compounds are known as gelling and stabilizing agents, which are widely used in the food industry. The scientific literature lacks precise information on the spectroscopy of apple pectin and citrus pectin. Therefore, the aim of this work was to test and compare the physicochemical properties of these compounds. The curves of FT-IR, NMR, ESI-MS, and thermogravimetric analysis (TGA) of pectin samples were measured and discussed. The analysis of the spectroscopic results confirms that the isolated pectins using various enzymes (xylanase and cellulase) have a structure similar to the commercially available pectin (PectaSol-C), with a noticeable change in morphology. These characteristics are helpful for further basic research and application.

Voltage-gated potassium channel Kv1.3 is an integral membrane protein, which is selectively permeable for potassium ions and is activated upon a change of membrane potential. Channel activation enables transportation of potassium ions down their electrochemical gradient. Kv1.3 channel is expressed in many cell types, both normal and cancer. Activity of the channel plays an important role in cell proliferation and apoptosis. Inhibition of Kv1.3 channel may be beneficial in therapy of several diseases including some cancer disorders. This review focuses on Kv1.3 channel as a new potentially attractive molecular target in cancer therapy. In the first part, changes in the channel expression in selected cancer disorders are described. Then, the role of the channel activity in cancer cell proliferation and apoptosis is presented. Finally, it is shown that some low molecular weight organic inhibitors of the channel including selected biologically active plant-derived polycyclic compounds may selectively induce apoptosis of Kv1.3-expressing cancer cells while sparing normal cells and healthy organs. These compounds may be promising candidates for putative application in therapy of some cancer disorders, such as melanoma, pancreatic ductal adenocarcinoma (PDAC), or B-type chronic lymphocytic leukemia (B-CLL).

The resistance of cancer cells to a variety of structurally non-related cytotoxic drugs is known as multidrug resistance phenomenon (MDR). In cellular membranes an activity of MDR transporters such as P-glycoprotein (ABCB1) is affected by their lipid environment. Many various compounds have been examined for their ability to restore drug-sensitivity of resistant cancer cells. Statins, inhibitors of the key enzyme of mevalonate pathway HMG-CoA (3-hydroxy-3-methyl-glutaryl-coenzyme A) reductase are drugs commonly prescribed in order to reduce serum level of cholesterol and to diminish the risk of cardiovascular disease. Statins as drugs that influence lipid composition of cell membrane and in that way they also exert influence on lipid bilayer properties appear to be good candidates as MDR modulators. In this work it was shown that statins - mevastatin and simvastatin exert antiproliferative, pro-apoptotic and reversing drug resistance effect in human colon adenocarcinoma cell line LoVo and its drug-resistant subline LoVo/Dx. A hypothesis was also checked whether flavones, which as it is well known are able to influence the biosynthesis of cholesterol, may change the anticancer activity of statins. Our investigations have revealed that combined use of statins and studied flavonoids results in enhanced cell growth inhibition and apoptosis and lower cancer cell proliferation as compared to the application only statins alone. Moreover, in drug resistant LoVo/Dx cells a stronger decrease of resistance to doxorubicine was observed in the presence of statins in combination with flavones as compared to the effect observed for statins only.