Antiinflammatory Effects in THP-1 cells Treated with Verbascoside Lorenza Speranza, 1 * Sara Franceschelli, 2 Mirko Pesce, 2 Marcella Reale, 3 Luigi Menghini, 4 Isabella Vinciguerra, 2 Maria Anna De Lutiis, 2 Mario Felaco 2 and Alfredo Grilli 2,5 1 Department of Biomorphology, University ‘G. d’Annunzio’, Chieti, Italy 2 Department of Human Dynamics, University ‘G. d’Annunzio’, Chieti, Italy 3 Department of Drug Sciences, University ‘G. d’Annunzio’, Chieti, Italy 4 Department of Biomedical Sciences, University ‘G. d’Annunzio’, Chieti, Italy 5 On line University ‘Leonardo Da Vinci’ Torrevecchia Teatina, Chieti, Italy 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 pathophysiologi- cal 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-γ, 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 μM. 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 pro- duction of superoxide radicals and consequently reduces the activity of iNOS. Copyright © 2010 John Wiley & Sons, Ltd. Keywords: verbascoside; inflammation; iNOS; antioxidant network. INTRODUCTION Verbascum thapsus plants are very common in the Italian region of Abruzzo and are used locally as a remedy to cure topical inflammatory processes in humans and animals. Verbascum spp. comprises at least 360 species, some of which are used in ethnomedical traditions of many countries all over the world. Verbascum spp. are native to Europe and Asia and many species grow wild on stony ground, in wasteland, woodland, clearings and roadsides. The most studied species is Verbascum thapsus, commonly known as ‘mullein’, the use of which in folk medicine has been reviewed recently by Gurel and Turker (2005) (Farideh et al., 2007). Since ancient times, common mullein has been used as a medicinal herb, leaf extracts of Verbascum thapsus have been shown to be active against bovine herpes virus type 1, and showed slight antibacterial and anti- fungal activity (McCutcheon et al., 1992, 1994, 1995). During the past decade its use in traditional medicine has expanded globally and is gaining popularity. It has continued to be used not only for primary health care of the poor in developing countries but also in countries where conventional medicine is predominant in the national health care system (Turker and Camper, 2002). The constituents of Verbascum thapsus include polysac- charides, iroid glycosides, flavanoid, saponin, volatile oil and phenylpropanoids. Phenylpropanoids are a class of polyphenolic compounds distributed in many medicinal plants (Yong et al., 1998). Some of them are reported to have cytostatic, cardioactive and hepatocytic effects, in particular, acteoside (also called verbascoside), a repre- sentative phenylpropanoid, possesses antiinflammatory effects (De Pascual et al., 1978). In fact, an increasing body of evidence suggests that many plants have anti- oxidant activities that could be therapeutically benefi- cial (Saltan et al., 2004). Inflammation is a complex process that is initiated by several mediators. It is char- acterized by oxidative stress and nitric oxide (NO) (Eliott and Wallance, 1998). The oxidative stress deter- mines the activation of a network of antioxidants, including NO, as well as increased production of the O 2 radical from the induction of NF-kB which activates iNOS (White, 1999; Karim, 1999). The role of nitric oxide in inflammation has been studied extensively (Grisham et al., 2001). A number of reports have dem- onstrated that this compound possesses regulatory anti- inflammatory activity, whereas other studies suggest that it promotes inflammation and tissue dysfunction, and thus possesses deleterious pro-inflammatory prop- erties (Pichika and Homandberg, 2004). Nitric oxide is a free radical produced in mammalian cells constitutively or induced by various cell activators through the oxidation of l-arginine by a family of iso- * Correspondence to: Lorenza Speranza, Department of Biomorphology, University ‘G. D’Annunzio’, Via dei Vestini, 31 66123 Chieti Italy. E-mail: l.speranza@unich.it Received 15 October 2009 Revised 15 February 2010 Copyright © 2010 John Wiley & Sons, Ltd. Accepted 01 March 2010 PHYTOTHERAPY RESEARCH Phytother. Res. 24: 1398–1404 (2010) Published online 1 June 2010 in Wiley Online Library (wileyonlinelibrary.com) DOI: 10.1002/ptr.3173