Anti-inflammatory and Antioxidant Activities of Steviol Glycosides

In this experiment,the cytotoxicity and anti-inflammatory activity of stevia compounds on mouse macrophage Raw264.7 cells was investigated with 6 representative steviol glycosides along with their intestinal metabolite steviol as well as steviol’s rearrangement product isosteviol. Meanwhile,the antioxidant activity of the above stevia compounds and their cytotoxicity and anti-inflammatory activity against Raw264.7 of murine macrophages were investigated. The results showed that the stevia compounds had no cytotoxicity,nor induced inflammatory reaction in the range of 100 μg/mL. Isosteviol showed the best anti-inflammatory effect,when the isosteviol concentration was 100 μg/mL,the NO contents produced by stimulation with lipopolysaccharide was reduced about 30.7%. The highest free radical scavenging abilities of the assayed steviol glycosides were 24.8%(DPPH·)and 13.8%(·OH),respectively. There had a structural correlation with the scavenging ability on DPPH free radicals,while there was no structural correlation on hydroxyl free radical clearance. When the experiment was carried out with stevia phenols,the DPPH· and ABTS⁺· scavenging rates were 92.1% and 29.6%,respectively. Therefore,the antioxidant activity of stevia extracts could be mainly caused by the stevia phenols.