Nauclea orientalis (L.) Bark Extract Protects Rat Cardiomyocytes from Doxorubicin-Induced Oxidative Stress, Inflammation, Apoptosis, and DNA Fragmentation

The therapeutic efficacy of anthracycline antibiotic, doxorubicin (Dox), is hampered due to the dose-dependent cardiotoxicity. The objective of the study was to explore the counteraction of aqueous bark extract of Nauclea orientalis in Dox-induced cardiotoxicity in Wistar rats. The acute and subchronic toxicity study performed with 2.0 g/kg of the plant extract revealed biochemical and haematological parameters to be within the physiological range, and no histological alterations were observed in any organs isolated. Screening of plant extract for the protection of the myocardium from Dox-induced oxidative stress, inflammation, and apoptosis was performed on five groups of rats: control, plant extract control, Dox control (distilled water (D.H2O) 2 weeks + on the 11(th) day single injection of Dox, 18 mg/kg), plant + Dox (2.0 g/kg plant extract 2 weeks + on the 11(th) day Dox, 18 mg/kg), and positive control, dexrazoxane. A significant increase in cardiac biomarkers and lipid peroxidation (p < 0.001) and a significant decrease in antioxidant parameters (p < 0.001) were observed in the Dox control group. All these parameters were reversed significantly (p < 0.05) in the plant-pretreated group. The histopathological assessment of myocardial damage provided supportive evidence for the biochemical results obtained. Inflammatory markers, myeloperoxidase, expression of TNF alpha and caspase-3, and DNA fragmentation (TUNEL positive nuclei) were significantly elevated (p < 0.05), and expression of Bcl-2 was significantly decreased (p < 0.05) in the Dox control; however, all these parameters were significantly reversed in the plant extract-treated group. In conclusion, the aqueous bark extract of Nauclea orientalis (2.0 g/kg) has the ability to attenuate the Dox-induced oxidative stress, inflammation, apoptosis, and DNA fragmentation in Wistar rats.