Doxorubicin (DOXO) induces marked cardiotoxicity, though increased oxidative stress
while there are some documents related with cardioprotective effects of some antioxidants
against organ-toxicity during cancer treatment. Although magnolia bark has some antioxidant-like
effects, its action in DOXO-induced heart dysfunction has not be shown clearly. Therefore,
here, we aimed to investigate the cardioprotective action of a magnolia bark extract
with active component magnolol and honokiol complex (MAHOC; 100 mg/kg) in DOXO-treated
rat hearts. One group of adult male Wistar rats was injected with DOXO (DOXO-group;
a cumulative dose of 15 mg/kg in 2-week) or saline (CON-group). One group of DOXO-treated
rats was administered with MAHOC before DOXO (Pre-MAHOC group; 2-week) while another
group was administered with MAHOC following the 2-week DOXO (Post-MAHOC group). MAHOC
administration, before or after DOXO, provided full survival of animals during 12-14 weeks,
and significant recoveries in the systemic parameters of animals such as plasma levels
of manganese and zinc, total oxidant and antioxidant statuses, and also systolic and
diastolic blood pressures. This treatment also significantly improved heart function
including recoveries in end-diastolic volume, left ventricular end-systolic volume,
heart rate, cardiac output, and prolonged P-wave duration. Furthermore, the MAHOC
administrations improved the structure of left ventricles such as recoveries in loss
of myofibrils, degenerative nuclear changes, fragmentation of cardiomyocytes, and
interstitial edema. Biochemical analysis in the heart tissues provided the important
cardioprotective effect of MAHOC on the redox regulation of the heart, such as improvements
in activities of glutathione peroxidase and glutathione reductase, and oxygen radical-absorbing
capacity of the heart together with recoveries in other systemic parameters of animals,
while all of these benefits were observed in the Pre-MAHOC treatment group, more prominently.
Overall, one can point out the beneficial antioxidant effects of MAHOC in chronic
heart diseases as a supporting and complementing agent to the conventional therapies.