## 4 Discussion
The most abundant endocellular lipid peroxidation products are HNE, MDA, and ONE. At the same time, acrolein, present in a cell in high amounts, is derived from other sources, such as smoking, fried food, etc. The following levels of aldehydes HNE, ONE and MDA, as presented in Figure 1, have been found in human plasma: 0.564 \(\pm\) 0.467 nM, 0.299 \(\pm\) 0.248, and \(>\)1 uM, respectively [14; 46]. The local concentration of total LPO products in the microsomal and mitochondrial layer is approximately 10 mM [47], and more than 200 products have been identified to date [48]. It should be pointed out that the above level varies depending on a person's age, health condition, and the analytical techniques used. Indeed, because of the products' reactivity and resulting instability, ascertaining a precise measurement still poses a huge analytical challenge. However, the half-lives of HNE and ONE in physiological conditions, for example, have been estimated at 2 min [49; 50]. This provides enough time for them to react with the exo-amino group of nucleobases, leading to ethano-type adducts via Michael addition [51]. It should be noted that the exo-amino groups involved in DNA base pairing are less available to LPO products, making them less abundant in the genome than \({}^{0X0}\)G, i.e., 14.6 per 10\({}^{6}\) nucleotides (nt) [52]. The levels of \(\varepsilon\)-dCyt, \(\varepsilon\)-dAde, H-\(\varepsilon\)-dGua, N2,3-\(\varepsilon\)-\(\varepsilon\)-dGua, (\(R/S\)) 10-OH-PdGua, H-\(\varepsilon\)-dCyt, H-\(\varepsilon\)-dAde, H-\(\varepsilon\)-dGua, HNE-dGua, and M1-dGua in calf thymus DNA have been assigned as follows (per 10\({}^{7}\) nt): 7.63, 12.4, 1.08,0.7-7 3.71, 5.81, 2.10, 2.28, 1.42, and 2.87, respectively [53; 54]. The radicals formed and stabilised from nucleosides or lipids are not uniformly distributed over the cellular environment during exposure to harmful factors, such as ionisation radiation, xenobiotics, etc. It is well known that the process initiated by destructive factors, such as radiation, can create different reactive forms, such as radicals [55]. These molecules can migrate and become trapped by certain preferred molecules present in the cytosol. Both the abundant and reactive aldehyde. along with the commonly present nucleobase moieties. can trigger changes to the antioxidant potential of a cell. Experimentally determining the ionisation potential of 2\({}^{\prime}\)-deoxynucleosides and their analogues presents some analytical challenges, including the preparation of intact gas-phase nucleosides, nucleotides, or nucleic acid bases and their derivatives. Therefore, little experimental data exist in the literature, most of which focuses on free bases. As a result of these limitations, IPs were computed by various theoretical methods [56]. As mentioned above, the following order of ionisation potentials was assigned: U \(>\) T \(>\) C \(>\) A \(>\) G, establishing guanosine as the most susceptible to one-electron oxidisation and radical cation trapping among all the canonical nucleosides [57]. In this study, the 2\({}^{\prime}\)-deoxynucleoside adducts with lipid peroxidation products, as shown in Figure 2, were taken into theoretical consideration. The spatial geometries of the neutral and radical cation forms were optimised at the M06-2x/6-31++G** level of theory in the aqueous phase. The 3D structure comparison between neutral and oxidised forms of LPO derivatives reveals the lowest RMSD value (0.156 [\(\AA^{2}\)]) for (_RSS_)HNE-dGua, with a \(\Delta\)DM equal to 1.8 [D]. Conversely, for \(N\)2,3-OH-\(\epsilon\)-PdGua, the highest RMSD and \(\Delta\)DM values were calculated as 0.650 and 5.49, respectively. The above indicates significant structural changes forced by electron loss, making \(N\)2,3-OH-\(\epsilon\)-PdGua less predisposed to oxidisation among all the 2\({}^{\prime}\)-deoxynucleosides adducts under discussion.