Reactive oxygen species (ROS)-mediated oxidative stress in chronic liver diseases and its mitigation by medicinal plants

Abstract

Reactive oxygen species (ROS) play a crucial role in cell survival regulation, and its low levels may act as indicators to encourage cellular proliferation. In contrast, elevated levels of ROS may lead to apoptosis. Stability between generating and eliminating ROS allows the retention of effective functioning of redox-sensitive signaling proteins under physiologic conditions. Cells typically maintain redox homeostasis to guarantee appropriate responses to internal and external stimuli. However, oxidative stress occurs when the oxidation product level exceeds the number of standard antioxidant systems. ROS can cause harm to all types of hepatic cells, including endothelial cells, hepatocytes, Kupffer cells, and stellate cells. High levels of ROS may lead to tissue edema, ischemia, fibrosis, cell death, or malignant transformation and may eventually lead to complete tissue damage. Antioxidants in our body exist in a homeostatic balance with other enzymes involved in the repair of cellular functions in addition to the non-enzymatic molecules such as urate, bilirubin, several vitamins, and reduced glutathione to maintain the levels of ROS in the interest of cellular homeostasis. This balance may, however, get disturbed in case of acute or chronic liver injury due to the accumulation of ROS. In the current manuscript, we aim to review the relevance of oxidative stress and its indicator of liver injury in chronic liver diseases such as alcoholic and non-alcoholic fatty liver diseases and hepatitis. Since reactive oxidation species may also lead to lipid peroxidation and promote ferroptosis, we have also evaluated their impact on epigenetic modifications, such as oxidative damage to histone proteins and DNA methylation, and the differential expression of genes related to cellular injury. We also want to highlight the potential of traditional herbal medicines as redox regulators for managing chronic liver diseases.

Keywords: Reactive oxygen species; alcoholic liver disease; herbal medicine; oxidative stress.