The antioxidant activities of natural sweeteners, mogrosides, from fruits of Siraitia grosvenori

To search for antioxidant agents from natural resources, in this paper the in vitro antioxidant activities of two natural sweeteners, mogroside V and 11-oxo-mogroside V isolated from the fruits of Siraitia grosvenori, were determined using chemiluminescence (CL). The results showed that these sweet glycosides, having cucurbitane triterpenoid aglycon, exhibited significant inhibitory effects on reactive oxygen species (O-2(-), H2O2 and center dot OH) and DNA oxidative damage. 11-oxo-mogroside V showed a higher scavenging effect on O-2(-) (concentration at which 50% of chemiluminescence intensity is inhibited [EC50] = 4.79 mu g/ml) and H2O2 (EC50 = 16.52 mu g/ml) than those of mogroside V. However, mogroside V was more effective in scavenging center dot OH, with EC50 = 48.44 mu g/ ml compared with that of 1-oxo-mogroside V (EC50 = 146.17 mu g/ml). Further, 11-oxo-mogroside V exhibited a remarkable inhibitory effect on center dot OH-induced DNA damage with EC50 = 3.09 mu g/ ml.