## 1 Introduction
The arrangement of chemical bonds in the structure of methyl sulfone is almost identical to that of the well-known compound binding the microtubules in cells [22]. DMSO was once considered to be a promising new anti-cancer drug, mostly because it causes induction of polymerization and stabilization of microtubules. Extensive studies have shown that DMSO has no anti-cancer properties [12]. Equisetum (horsetail) is widely found in grasslands and contains high levels of methyl sulfone, and it can be a useful compound with effective and chemotherapeutic impact for metastatic melanoma cells treatment and other possible treatments of metastatic cancers [23]. Horsetail extracts were applied to two human cancer cell lines: HeLa, HT-29, and MCF7. The results of electron spin resonance (ESR) analysis confirmed that the investigated extracts suppressed the formation of lipid peroxyl radicals in a dose-dependent manner. The results show that n-butanol, methanol, ethyl acetate, and water extracts have significant peroxyl radical scavenging activity. Additionally, the chosen extracts repressed the interphase of cells depending on specific cell line and their concentration. Ethyl acetate extract showed the largest outstanding antiproliferative effect without inducing any cell growth stimulation on human tumour cell lines. According to the results obtained, horsetail extracts could be used as a natural source of antioxidants and as potential phytochemicals [14]. The analysis emphasized that some extracts were beneficial antioxidants in comparison to the reference molecules, vitamin E and quercetin. A correlation was found between the total amount of phenolic compounds contained in the extracts and antioxidant effects. Significant effects of the extract on proliferation of melanoma B16 cells were studied and reported [15]. In other studies, phytochemicals present in grapes have also shown potential anticancer activity in preclinical and clinical studies [24; 25; 26]. One such phytochemical is resveratrol. Additional extracts attained from various parts of grapes have been tested for their cytotoxic effect on different cell lines: MCF-7 cells, A427 lung cancer cells, gastric adenocarcinoma CRL-1739 cells, A549 and H1299 lung cancer cells, Cal27 and SCC25 oral squamous cell carcinoma cells, and Jurkat cells. The extracts were also tested for antioxidant activity effect (UV-B induces skin carcinogenesis), anti-inflammatory effect (TNBS induces ulcerative colitis rat model), apoptosis of cells (DU145 and LNCaPP), antiangiogenic (MCF-7, MDA-MB-231), and antimetastatic effects (4T1 Breast cancer cells) [27]. A correlation was also found between antioxidant effects and the total amount of phenolic compounds contained from the extracts, which results in a significant effect on the proliferation of melanoma B16 cells [15]. This study analysed the influence of antioxidant activity, proanthocyanidins and total phenols from selected natural materials (curcuma, goji berries, horsetail, rosemary, marc and seeds of grape) on the human melanoma cell line, to which these extracts have never been applied, and the literature concerning similar research is scarce. To determine the metabolic activity (the sum of the chemical reactions that take place within each cell of a living organism and that provide energy for vital processes and for synthesizing new organic material) of these cells, the WST 8 test was employed.