in vitro and in vivo assessment of inhibitory effect of stevioside on pro-inflammatory cytokines

objective: stevioside is a natural non-caloric sweetener which has been reported to have anti-inflammatory activity.  the aim of  the present study was to examine in vitro and in vivo effects of  stevioside on rats  plasma levels of tumor necrosis factor- α (tnf-α),  interleukin-1β (il-1β), tnf-α and il-1β release from lipopolysaccharide(lps)-stimulated rat peripheral blood mononuclear cells (pbmcs). materials and methods: male wistar rats weighing between 170-220 g were given stevioside (0, 500 and 1000 mg/kg bw/day) for 6 weeks. mononuclear cells were separated from peripheral blood samples.  tnf-α and il-1β levels in plasma and the release of tnf-α and il-1β from pbmcs were determined using rat enzyme-linked immunosorbent assay (elisa) kits. results:  plasma levels of tnf-α and il-1β were found to be non-detectable in control and groups treated with 500 and 1000 mg/kg of stevioside.  regarding tnf-α release from lps-stimulated    pbmcs, rats that were orally fed with 500 and 1000 mg/kg of stevioside were significantly different (p<0.05) from those in lps-treated control group (186.8+18.6 and 151.4 + 15.4 vs 248.6+21.4 pg/ml).  additionally, il-1β levels in rats treated with 500 and 1000 mg/kg of stevioside were significantly different (p<0.05) from those in lps-treated control group (220.0+12.1 and 158.1 + 22.6 vs 294.4+16.1 pg/ml). conclusion:  consumption of stevioside has an inhibitory effect on the release of tnf-α and il-1β from lps-stimulated pbmcs in rats.