lignans and Cerebral-Infarction

Neuroprotective efficacy of magnolol, 5,5'-dially-2,2'-dihydroxydiphenyl, was investigated in a model of stroke and cultured neurons exposed to glutamate-induced excitotoxicity. Rats were subjected to permanent middle cerebral artery occlusion (pMCAO). Magnolol or vehicle was administered intraperitoneally, at 1 hr pre-insult or 1-6 hrs post-insult. Brain infarction was measured upon sacrifice. Relative to controls, animals pre-treated with magnolol (50-200 mg/kg) had significant infarct volume reductions by 30.9-37.8% and improved neurobehavioral outcomes (P<0.05, respectively). Delayed treatment with magnolol (100 mg/kg) also protected against ischemic brain damage and improved neurobehavioral scores, even when administered up to 4 hrs post-insult (P<0.05, respectively). Additionally, magnolol (0.1 µM) effectively attenuated the rises of intracellular Ca(2+) levels, [Ca(2+)](i), in cultured neurons exposed to glutamate. Consequently, magnolol (0.1-1 µM) significantly attenuated glutamate-induced cytotoxicity and cell swelling (P<0.05). Thus, magnolol offers neuroprotection against permanent focal cerebral ischemia with a therapeutic window of 4 hrs. This neuroprotection may be, partly, mediated by its ability to limit the glutamate-induced excitotoxicity.

Topics: Animals; Biphenyl Compounds; Brain; Calcium; Cells, Cultured; Cerebral Infarction; Dose-Response Relationship, Drug; Glutamic Acid; Infarction, Middle Cerebral Artery; Injections, Intraperitoneal; Lignans; Male; Neurons; Neuroprotective Agents; Neuropsychological Tests; Rats; Rats, Sprague-Dawley; Time Factors

Fruits of Schisandra have been traditionally used in East Asia for the treatment of dyspnea, cough, dysentery, insomnia, tonic-clonic seizures, and amnesia. Schisandrin B, a dibenzocyclooctadiene derivative isolated from Fructus Schisandrae, has been shown to produce antioxidant effect on rodent liver and heart. In the present study, we investigated the neuroprotective effects of Schisandrin B, a constituent drug of the fruit of Schisandra, against focal cerebral ischemia in rats. Schisandrin B (10, 30 mg/kg, i.p.) was twice administered 30 min before the onset of ischemia and 2h after reperfusion. Schisandrin B 10 and 30 mg/kg treated groups showed infarct volumes reduced by 25.7% and 53.4%, respectively, 2h after occlusion. Also, Schisandrin B treated animal treatment abrogated protein expression of TNF-α and IL-1β and degradation of MMP-2 and MMP-9 in ischemic hemispheres. These results suggest that Schisandrin B treatment provides a neuroprotective effect to rats after transient focal cerebral ischemia by inhibiting inflammation and by protecting against metalloproteinase degradation.

Topics: Animals; Antioxidants; Cerebral Infarction; Cyclooctanes; Drugs, Chinese Herbal; Inflammation; Interleukin-1beta; Ischemic Attack, Transient; Lignans; Male; Matrix Metalloproteinase 2; Matrix Metalloproteinase 9; Neuroprotective Agents; Plant Extracts; Polycyclic Compounds; Rats; Rats, Sprague-Dawley; Reperfusion; Schisandra; Tumor Necrosis Factor-alpha

We have previously shown that honokiol, an active component of Magnolia officinalis, displayed protective effect against focal cerebral ischemia-reperfusion (FCI/R) injury in rats. Production of reactive oxygen species (ROS) and infiltration of neutrophils to injured tissue play deleterious roles during cerebral ischemia. To study the mechanism(s) in mediating neuroprotective effect of honokiol, FCI/R-induced neutrophil infiltration and lipid peroxidation in brain tissue, and activation of neutrophils in-vitro were examined. Intravenous administration of honokiol (0.01-1.0 microg/kg) 15 min before (pretreatment) or 60 min after (post-treatment) middle cerebral artery occlusion reduced the total infarcted volume by 20-70% in dose-dependent manner. Pretreatment or post-treatment of honokiol at concentration of 0.1 and 1.0 microg/kg significantly decreased the neutrophil infiltration in the infarcted brain. Time course of neutrophil infiltration was performed in parallel with the lipid peroxidation in infracted brain tissue during FCI/R injury. The results indicate that honokiol can protect brain tissue against lipid peroxidation and neutrophil infiltration during FCI/R injury and cerebral infarction induced by FCI/R is accompanied with a prominent neutrophil infiltration to the infarcted area during FCI/R course. In-vitro, honokiol (0.1-10 microM) significantly diminished fMLP (N-formyl-methionyl-leucyl-phenylalanine)- or PMA (phorbol-12-myristate-13-acetate)-induced neutrophil firm adhesion, a prerequisite step behind neutrophil infiltration, and ROS production in neutrophils. Intracellular calcium overloading activates calcium-stimulated enzymes and further exaggerates FCI/R injury. Honokiol (0.1-10 microM) impeded the calcium influx induced by fMLP (a receptor agonist), AlF(4)(-) (a G-protein activator) or thapsigargin (an intracellular calcium pool releaser). Therefore, we conclude that the amelioration of FCI/R injury by honokiol can be attributed to its anti-oxidative and anti-inflammatory actions through, at least in part, limiting lipid peroxidation and reducing neutrophil activation/infiltration by interfering firm adhesion, ROS production, and calcium overloading that may be primed/activated during FCI/R injury.

Topics: Animals; Biphenyl Compounds; Brain Ischemia; Calcium; Calcium Signaling; Cell Adhesion; Cerebral Infarction; Chemotaxis, Leukocyte; Dose-Response Relationship, Drug; Infarction, Middle Cerebral Artery; Lignans; Lipid Peroxidation; Male; N-Formylmethionine Leucyl-Phenylalanine; Neuroprotective Agents; Neutrophils; Rats; Rats, Long-Evans; Reactive Oxygen Species; Reperfusion Injury; Tetradecanoylphorbol Acetate