RESUMO
Smilax china L. is a traditional Chinese medicine mainly used for the treatment of pelvic inflammation. Polysaccharide might be one of the anti-inflammatory components of Smilax china L. Based on this hypothesis, this work aimed at extraction, purification and structural elucidation of Smilax china L. polysaccharides and their preliminary anti-inflammatory effects were also studied. Two polysaccharides named SCLP1 (Smilax china L. polysaccharide 1, 42.1kDa) and SCLP3-2 (Smilax china L. polysaccharide 3-2, 16.8kDa) were for the first time purified from Smilax china L. The structures of SCLP1 and SCLP3-2 were elucidated by chemical and spectral analysis. The results revealed that SCLP1 was a neutral polysaccharide composed of glucose and mannose (54.5:1.0). Its backbone was 1,4linked αGlcp interspersed with 1,2linked αGlcp and Manp; the branches were 1,6linked α-Glcp and terminated with αGlcp. SCLP3-2 was composed of galacturonic acid, arabinose, galactose and rhamnose (23.3:2.1:1.7:1.0) and was a pectin-type polysaccharide with an α1,4linked homogalacturonan backbone which was partially methyl-esterified and slightly acetylated. The side chains consisted of αRhap, ßGalp and αAraf. SCLP1 and SCLP3-2 could inhibit the production of NO, IL-6 and TNF-α in LPS-stimulated RAW264.7 cells via NF-κB and MAPKs (ERK1/2, JNK) pathways, indicating that they possessed a potential anti-inflammatory activity.
Assuntos
Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Polissacarídeos/química , Polissacarídeos/farmacologia , Smilax/química , Animais , Anti-Inflamatórios/isolamento & purificação , Citocinas/metabolismo , Hidrólise , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Espectroscopia de Ressonância Magnética , Camundongos , Estrutura Molecular , Extratos Vegetais/isolamento & purificação , Polissacarídeos/isolamento & purificação , Células RAW 264.7 , Espectroscopia de Infravermelho com Transformada de FourierRESUMO
The natural product totarol, a phenolic diterpenoid and a major constituent isolated from the sap of Podocarpus totara, has been reported to have a potent antimicrobial activity. In this study, we determined whether totarol possessed an additional neuroprotective activity in vitro and in vivo. We found that totarol prevented glutamate- and oxygen and glucose deprivation-induced neuronal death in primary rat cerebellar granule neuronal cells and cerebral cortical neurons. Totarol increased Akt and GSK-3ß phosphorylation, Nrf2 and heme oxygenase-1 (HO-1) protein expressions and suppressed oxidative stress by increasing GSH and SOD activities. The PI3K/Akt inhibitor LY294002 prevented totarol neuroprotective effect by suppressing the totarol-induced changes in HO-1 expression and the activities of GSH and SOD. The HO-1 inhibitor ZnPPIX also prevented totarol-increased GSH and SOD activities. In a model of acute cerebral ischemic injury in Sprague-Dawley rats, produced by occlusion of the middle cerebral artery for 2h followed by 22 h or 46 h of reperfusion, totarol significantly reduced infarct volume and improved the neurological deficit. In this model, totarol increased HO-1 expression and the activities of GSH and SOD. These observations suggest that totarol may be a novel activator of the Akt/HO-1 pathway protecting against ischemic stroke through reduction of oxidative stress.