Antioxidant Effects of Nigella sativa and Its Modulating Role on Hepatotoxicity Induced by Dietary Frying Oil in Rats

During the past few years, the consumption of fried foods is madly increased, and this is due to the preference of consumers, on one hand, and that the meal resulting from this process tastes delicious on the other hand. Unfortunately, most consumers do not know the risk of consuming fried foods repeatedly because during frying, various chemical reactions occur, including thermal oxidation, due to oil exposure to high temperatures in the presence of air and moisture. Consequently, cooking oil disintegrates and generates volatile and non-volatile components, different monomers, and polymers [1]. High temperatures associated with the repeated use of the same oil lead to the breakdown of some fatty acids, forming numerous toxic polymer compounds, polar compounds, and peroxides [2]. These toxic compounds eventually degrade the quality of the frying oil. Many studies suggest that the repeated use of frying oil can also change the configuration of fatty acids from the cis-isomer to the trans-isomer, resulting in unnatural and indigestible fatty acids [3].
When people continuously consume fried foods, which contain a considerable amount of oxidized oil containing dangerous reactive oxygen species (ROS) and toxic compounds, their bodies are constantly exposed to a state of harmful oxidative stress. This phenomenon is a resulting from an imbalance between an oxidative defense system and the hyperformation of oxidizing substances, including free radicals [2]. Oxidative stress is defined as a deep disturbance in the balance between pro-oxidants and antioxidants in favor of the former, which leads to irreversible cell damage…