Ameliorative role of melatonin against adrenaline induced oxidative stress mediated cardiac and hepatic tissue injuries through preserving pyridoxine metabolism in male Wistar rats: A mechanistic insight

Adrenaline (AD) is a naturally occurring catecholamine, synthesised in the adrenal medulla to prepare the organisms for a "fight or flight" response. Under stressful circumstances, the circulatory catecholamine undergoes auto-oxidation, resulting in the formation of free radicals. Chronic stress results in the depletion of micronutrient stores in the body. Pyridoxine, often known as vitamin B₆, is an essential water-soluble vitamin that acts as a coenzyme in many metabolic processes. Therefore, our current investigation has prioritized the regulation of pyridoxine metabolism during the period of chronic stress and the precise role of melatonin, as a natural antioxidant, in preventing the alterations generated by adrenaline in cardiac and hepatic tissues. Adrenaline augmented the oxidative stress indices, leading to an imbalance in the antioxidative state resulting in changes in the levels of certain organ-specific serum markers, modifications in the levels of PL (pyridoxal), PLP (pyridoxal-5-phosphate), and the enzymes responsible for their metabolism and breakdown. The foregoing results were corroborated by the histochemical and histological examinations. Melatonin efficiently counteracted all these harmful changes. Besides, the current study demonstrates that both PLP and melatonin show efficacy in scavenging free radicals, including superoxide anion free radicals and hydroxyl radicals, in the chemical system. However, the in vitro studies demonstrated that when administered together, melatonin and PLP more effectively mitigate free radical generation than the individual molecule. These findings were further confirmed by the ITC binding study. These results suggest that a combination of melatonin and PLP could be a better therapeutic approach for the amelioration of stress induced oxidative damages in cardiac and hepatic tissues with an improved pyridoxine metabolism.