Constituents of Pyrus pyrifolia with inhibitory activity on the NO production and the expression of iNOS and COX-2 in macrophages and microglia

Abstract

It is well known that inflammation is associated with neurodegenerative disorders, including Alzheimer's disease, Parkinson's disease and ischemia. Nitric oxide (NO), a pro-inflammatory mediator, is produced by inducible NO synthase (iNOS) in microglia as well as macrophages and appears to account for neurodegeneration. In this study, we aimed to isolate NO inhibitors from Pyrus pyrifolia by activity guided purification. As a result, we identified daucosterol and β-sitosterol, which have not been isolated from this plant before. This article also describes NO inhibitory activities of the methanol extract of Pyrus pyrifolia fruit and the isolated compounds from this, which are lupeol, betulin, betulinic acid, β-sitosterol and daucosterol, in LPSactivated RAW 264.7 and BV2 cell lines. Western blot analysis was performed to clarify the underlying mechanism of NO inhibition in the two cell lines.