Doxorubicin (DOX) has been linked with impairment in cardiovascular function and redox balance. In the present study, the effect of Phyllanthus amarus (PA) and Momordica charantia (MC) leaves on some biomolecules [Angiotensin-I converting enzyme (ACE), arginase, acetylcholinesterase (AChE), adenosine deaminase (ADA), lactate dehydrogenase (LDH)] and antioxidant [catalase (CAT), superoxide dismutase (SOD), glutathione (GSH) and malondialdehyde (MDA)] linked with cardiac function in DOX-stressed rats was evaluated. Animals were grouped and pretreated with PA and MC leaf extracts at different doses (200 and 400 mg/kg/bwt orally), while DOX (15 mg/kg/bwt) was administered intraperitoneally on the last day of the experiment. Result revealed an increase of ACE, arginase, AChE, ADA, LDH activities and MDA level as well as a significant reduction in CAT and SOD activities, and GSH level in the rats treated with DOX compared to the control. However, these were significantly mitigated in the rats pretreated with PA and MC dose dependently. Chemical characterization of the leaf extracts via high performance liquid chromatography revealed the presence of some phenolic compounds which included kaempferol, catechin, epicatechin, ellagic acid, gallic acid quercetin, isoquercitrin and rutin. These findings revealed a significant improvement in redox imbalance and other biomolecules associated with cardiac function, which was altered by DOX. This improvement could be linked to the presence of cardioprotective agents present in PA and MC, thereby making these plants therapeutic agents for the treatment of cardiovascular complications associated with drugs such as DOX.