The protective efficacy of magnolol in hind limb ischemia-reperfusion injury

We investigated the protective effects of magnolol, an active antioxidant and free radical scavenger extracted from Magnolia officinalis, in a hind limb ischemic-reperfusion animal model. Adult male Spraque-Dawley rats were subjected to hind limb ischemic insult for 2 hours and were intravenously treated with magnolol at 0.01 mg/kg (n=8), 0.3 mg/kg (n=8) mg/kg or 1 mg/kg (n=8) mg/kg, or vehicle (n=8). At 24 h post-insult, the levels of nitrite/nitrate (NOX), malondialdehyde (MDA) and myeloperoxidase (MPO), as well as the degree of muscle damage, were assessed. Relative to controls, animals treated with magnolol (0.3 and 1 mg/kg) had attenuated muscular inflammation, edema and damage. Magnolol (0.3-1 mg/kg) also effectively reduced postischemic rises in the MDA, NOx and MPO levels (p<0.05, respectively). Magnolol administrated at 0.01 mg/kg, however, failed to protect against the ischemic-perfusion limb injury. In addition, magnolol (0.01-1 mg/kg) did not affect local muscular blood reperfusion or other physiological parameters, including hematocrit, glucose, arterial blood gases and mean arterial blood pressure. Thus, intravenous administration with magnolol at 0.3-1 mg/kg protects against ischemic limb damage in rats. This cytoprotection may be attributed to its antioxidant, anti-nitrosative and anti-inflammatory actions.