Methanolic Extract of Micromeria frivaldszkyana (Degen) Velen Alleviates Tert-Butyl Hydroperoxide-Induced Hepatic Damage and Renal Function-Related Serum Biomarkers in Male Wistar Rats

Plant-derived compounds have recently attracted considerable scientific attention due to their potential therapeutic applications, which are largely attributed to their antioxidant properties. Tert-butyl hydroperoxide (t-BHP) is a potent inducer of intracellular oxidative stress, generating reactive free radicals, which significantly contribute to hepatic and renal damage. Micromeria frivaldszkyana (M. frivaldszkyana), a Bulgarian endemic species, contains high levels of phenolic compounds, including linarin, rosmarinic acid (RA), chlorogenic acid, rutin, quercetin, naringenin, and apigenin. In this study, male Wistar rats received oral treatment for 5 days comprising saline, 250, 400, or 500 mg/kg of M. frivaldszkyana methanolic extract, 100 mg/kg RA, or 125 mg/kg silymarin. On the final day, 0.5 mmol/kg of t-BHP was injected intraperitoneally, and blood and liver tissue samples were collected 18 h later for biochemical and histological analysis. Liver and kidney function was evaluated using biochemical markers (alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, creatinine (Cr), uric acid (UA)), indicators of oxidative stress (malondialdehyde (MDA), 8-hydroxy-2′-deoxyguanosine (8-OHdG), glutathione (GSH), superoxide dismutase (SOD), catalase (CAT)), and histopathology. Exposure to t-BHP resulted in significant hepatic and renal damage, including elevated serum markers, increased lipid peroxidation, and deoxyribonucleic acid (DNA) damage. Administration of 500 mg/kg M. frivaldszkyana markedly lowered elevated serum ALT and AST levels. The extract also significantly mitigated t-BHP-induced increases in serum Cr and UA. However, no significant increase in the levels of the antioxidant enzymes SOD and CAT or in GSH was observed at all tested doses. Malondialdehyde and 8-OHdG levels increased markedly following t-BHP exposure, whereas pretreatment with M. frivaldszkyana at all tested doses significantly ameliorated these oxidative alterations. These findings suggest that the methanolic extract of M. frivaldszkyana confers protective effects against t-BHP-induced toxicity, potentially through stabilisation of cell membranes, inhibition of lipid peroxidation, and reduction in DNA damage. The extract may therefore serve as a potential natural therapeutic agent against injuries caused by oxidative stress.