**5.2 Protein degradation**

Protein oxidation is considered as the damage of proteins. To understand the level of extent of this effect, the protein carbonyl content is the marker

to understand oxidative damage in rats that have been treated with ACR. The Dinitrophenylhydrazine (DNPH) assay is used to measure the levels of proteinhydrazone to quantify the protein carbonyl content [42].

#### **5.3 DNA damage**

Since GA binds to the DNA and causes detrimental effects, it is important to understand the genotoxicity of ACR on rats. A commonly used DNA damage marker for oxidative stress is 8-OHdG, which is quantified by ELISA kits [52]. The principle mechanism of ACR-induced neurotoxicity is widely accepted to be apoptosis induced by ACR in rats [33]. ROS induces cell death via apoptotic mechanisms that are either non-physiological or controlled [53]. Telomerase reverse transcriptase (TERT) is an apoptosis-related molecule and is influenced by oxidative stress because of its anti-apoptotic effect. When ACR was administered to rats TERT associated mRNA and protein expression was downregulated in the rat brain [33, 54]. The sensitivity of cells to various apoptotic stimuli is determined by the ratio of antiapoptotic protein B-cell lymphoma 2 (Bcl2) to pro-cell death proteins such as Bax and Bad, these ratios and the relative density of caspase-3 and caspase-9 is higher in ACR treated rats [37, 41, 55]. Proteins involved in apoptosis signalling pathways and cellular functions are also influenced by the presence of ACR. An appropriate balance must be maintained within the mitogen activated protein kinases (MAPKs) for regulating apoptosis. But, when ACR is induced, due to excessive ROS production a reduction in P-ERK/ERK ratio and elevation in the P-JNK/JNK and P-P38/P38 is observed, this causes mitochondrial dysfunction [1, 41].
