Stevioside, a diterpenoid glycoside, shows anti-inflammatory property against Dextran Sulphate Sodium-induced ulcerative colitis in mice

Inflammatory bowel disease is an umbrella-term used to describe a set of chronic inflammatory conditions that affect the gastro-intestinal tract. Since most of the inflammatory medications in current use have several undesirable side-effects, stevioside, a naturally occurring, high-intensity sweetener was assessed in our study for its anti-inflammatory properties by in-vitro and in-vivo experiments. Stevioside was observed to significantly inhibit the levels of LPS induced elevation of cytokines, TNF-α (P < 0.05) and IL-6 (P < 0.001) as well as the production of reactive oxygen species (P < 0.01) and nitrites (P < 0.001) in RAW264.7 cells. Stevioside has also been evaluated for its anti-inflammatory effect by using dextran sulfate sodium (DSS)-induced ulcerative colitis model in mice. Stevioside significantly reduced the disease activity index (DAI) score, ameliorated the inflammatory symptoms induced by DSS in mice and exhibited intact colon histo-architecture. Stevioside treatment significantly inhibited the levels of pro-inflammatory cytokines, TNF-α and IL-6, and the protein expressions of pro-inflammatory mediators, COX-2 (P < 0.01) and iNOS (P < 0.01) and restored the levels of endogenous anti-oxidants such as superoxide dismutase (P < 0.01), catalase (P < 0.001), glutathione s-transferase (P < 0.001) and reduced glutathione (P < 0.001) level in colon tissues. It was also observed that stevioside significantly suppressed NF-κB (p65) activation by abrogating IκB phosphorylation and attenuated the phosphorylation of p38, ERK and JNK proteins in colon tissues. The findings of the present study suggest that stevioside exhibits anti-inflammatory property by inhibiting NF-κB (p65) and MAPK pathways and can be employed as an adjunct in nutraceuticals to treat IBD.