Antiinflammatory effects in THP-1 cells treated with verbascoside.

Verbascum thapsus commonly known as 'mullein' is part of a large family of Scrophulariaceae consisting of more than 360 species. From antiquity Verbascum thapsus has been used as a medicinal herb, it contains diverse polysaccharides, iroid glycosides, flavonoids, saponins, volatile oils and phenylentanoids. Inducible nitric oxide synthase (iNOS) represents one of the three isoforms that produce nitric oxide using L-arginine as a substrate in response to an increase in superoxide anion activated by NF-kB. It is implicated in different pathophysiological events and its expression increases greatly during an inflammatory process, due to oxidative stress and the activation of the enzymes of the antioxidant network such as SOD, CAT and GPx.In this study an inflammatory state was reproduced by treating THP-1 cells (human myelomonocytic leukaemia) with pro-inflammatory stimuli, such as LPS and IFN-gamma, obtaining an up-regulation both in the expression and in the activity of iNOS. The aim of the work was to investigate the antiinflammatory action of verbascoside using a concentration of 100 mum. The results show a significant decrease of the expression and activity of iNOS, extracellular O(2) (-) production, SOD, CAT and GPx activity when the cells were treated with verbascoside. Based on these results it is hypothesized that verbascoside has antiinflammatory properties since it reduces the production of superoxide radicals and consequently reduces the activity of iNOS. Copyright 2010 John Wiley & Sons, Ltd.