In this doctoral thesis, the biological potential of four series of new L-ascorbic acid (L-ASA) structurally different derivatives (67 in total) was investigated. The structures were different regarding the substituents on the triazole ring and double covalent bond between the C-4 and C-5 atoms. Based on the observed antiproliferative effect on tumor and untransformed cell lines, two derivatives (4e and 8m) with the most selective and strongest effect on MCF-7 cells were chosen for further investigation. The predicted mechanism of action of all derivatives was investigated in silico by the QSAR (Quantitative structure - activity relationship) method, which also proposed the most potential target protein of the selected derivates - CDC25A protein (determined for 28.35% of the derivatives tested). The results of PASS (Prediction of Activity Spectra for Substances) analysis showed the potential chemoprotective effect of both selected derivatives. The biological mechanism of action for derivatives that showed significant antiproliferative effect was further investigated and validated by metabolic status analysis accompanied by proteomics methods. The biological processes associated with hypoxia inducible factor - 1α (HIF-1α ) regulated cellular signaling have been proposed as potential mechanism of action of derivatives with the strongest antiproliferative effect. In addition, the structures that showed antioxidant properties were further subjected to the analysis of antioxidant activity by the DPPH method. The results of DPPH analysis revealed antioxidant activity for derivatives having a 1,2,3-triazolyl bonded with an ethylene linkage, with a benzylated lactone ring, and a C-6 substituted 1,2,3-triazole derivatives of L-ASA with double bond at position C4 = C5. In addition, the results of analysis of cellular metabolism showed that individual derivatives from the group of free hydroxyl groups at C-2 and C-3 atoms and from the group C-6 substituted 1,2,3-triazole dibenzyl derivatives of L-ASA did not affect mitochondrial function. In conclusion, 1,2,3-triazole derivatives of L-ASA are novel potential antitumor and antioxidant structures that can be used to develop anticancer agents or as antioxidants by further chemical optimization.