## 4 Discussion  
In the current study, the effect of silica nanoparticles was evaluated with experiments to assess the antioxidant and protective effects of oleaster oil against silica nanoparticle-induced toxicity in Wistar rats. Polyphenols are well-recognized antioxidant compounds, and their presence in olive oil is associated with a range of beneficial properties, including improved stability, enhanced nutritional value, and enhanced sensory characteristics [45]. According to the classification proposed by [PERSON] et al. (1992) [46], which categorizes olive varieties based on their phenolic compound content, our olive oil belongs to the category of varieties with an average polyphenol content (less than 500 mg EAG/kg). Furthermore, several factors can influence polyphenol content, such as the olive variety, degree of ripeness, soil quality, the extraction process used, and storage conditions for the oil [47]. According to several authors, flavonoids are typically found in limited quantities in virgin oils [48]. These secondary metabolites possess the capability to scavenge free radicals, disrupt the catalytic lipid peroxidation reaction [49], and inhibit LDL oxidation [50]. These compounds, alongside other minor constituents in the oil, contribute to the sensory and organoleptic properties of the oil, as well as play a role in preventing oil self-oxidation. In addition, the qualitative and quantitative variations in total polyphenol and flavonoid content between different oils can be attributed to several factors, including climatic and environmental conditions, genetic heritage, harvesting period, plant development stage, and extraction methods. It is important to note that the quantification method used can also influence the estimation of total polyphenol and flavonoid content [51]. Figure 10: Effect of oleaster oil on histopathologic damage in the kidney after 5 weeks of treatment. Control group (C), (SiNPs) silica group. (SiNPs + Oleaster oil) Silica group treated with oleaster oil, and (O) Oleaster oil group. In our study, the results regarding oleaster oil's antioxidant activity against the DPPH radical demonstrated a significant inhibitory effect (63.92%). This substantial level of activity can be attributed to the oil's high concentration of secondary metabolites, such as polyphenols and flavonoids, which are recognized for their antioxidant properties. Oleaster oil's antioxidant and protective properties are attributed to its extensive mixture of fatty acids and minor bioactive compounds. Its primary fatty acids, in particular oleic, linoleic, and \(\alpha\)-linolenic acids, are known to contribute to cell integrity, delay the aging process, and provide anti-inflammatory benefits [52; 53]. The antioxidant activity of the oil is augmented by its minor components, which include terpen, sterols, phenolic compounds, and tocopherols. These compounds may mitigate the risks of cancer and aging-related diseases by reducing free radicals, protecting cellular structures, and preventing lipid oxidation [54]. Oleaster oil is beneficial for both antioxidant defense and overall health when consumed regularly. These antioxidants primarily exert their effects through the redox properties of their hydroxyl groups and the structural arrangement of various functional groups in their composition. This enables them to actively scavenge free radicals, function as reducing agents, deactivate singlet oxygen, chelate metals, and act as hydrogen donors. The formation of reactive oxygen species, such as superoxide and hydrogen peroxide, following exposure to xenobiotics leads to an imbalance between the body's antioxidant defense mechanisms and oxidative stress [51; 52; 53; 54; 45]. Recently, oxidative stress has frequently been reported as a toxic mechanism underlying silica nanoparticle-induced apoptosis and inflammation in various cell types, including macrophages, embryonic kidney cells, and epithelial cells [10; 11; 12; 56; 57].