Anti-inflammatory effects of Chinese medicinal herbs on cerebral ischemia

Activation of multiple inflammatory cascades accounts for the progressing of ischemia stroke [1]. After cerebral ischemia, energy depletion and necrotic neuron death in the local ischemic area start the inflammatory cascades. The reperfusion generates reactive oxygen species (ROS) that induce the production of cytokines and chemokines leading peripheral leukocytes to influx into the cerebral parenchyma and activate endogenous microglia. Then cellular immunity, adhesion molecules, inflammatory mediators, transcriptional factors participate in the inflammatory process.Anti-inflammatory treatment that inhibits specific steps of the inflammatory cascade is a new strategy for improving outcome after ischemia stroke [2-4]. The anti-inflammatory agents, including a variety of natural products used in Chinese medicine, have been shown to be able to prevent or treat ischemic stroke, by decreasing the infarct area and neurological deficiency [5]. These natural products are documented as anti-oxidative, anti-inflammatory, anti-apoptotic and neuro-functional regulatory agents [5]. Some active ingredients isolated from these herbs have been identified and demonstrated to have neuroprotective actions. Some of these compounds are andrographolide isolated from Andrographis paniculata (Chuan-xin-lian), oxymatrine isolated from Sophora flavescens (Ku-shen), quercetin isolated from Sophora japonica (Huai-hua), ferulic acid isolated from both Angelica sinensis (Dang-gui) and Ligusticum wallichii (Chuan-xiong), tetramethylpyrazine isolated from Ligusticum wallichii (Chuan-xiong), paeonol and paeoniflorin isolated from Paeonia lactiflora (Bai-shao), shikonin isolated from Lithospermum erythrorhizon (Zi-cao), vanillin, 4-hydroxybenzyl alcohol and 4-hydroxybenzyl aldehyde isolated from Gastrodia elata (Tain-ma), puerarin from Radix Puerariae (Pueraria lobata; Ge-gen), polydatin and emodin-8-O-β-D-glucoside isolated from Polygonum cuspidatum (Hu-zhang), tanshinone IIA isolated from Salviae