Radical scavenging activity of novel phenolic glycosides from Citrullus lanatus
Three new compounds (1 – 3) were isolated from the whole plant of Citrullus lanatus (Cucurbitaceae). The structures of these compounds were characterized by MS, IR, 1D and 2D NMR. The DPPH radical scavenging property of these compounds as well as vitamin C which served as the positive control group was determined. The result showed that Compound 3 exhibited the highest scavenging activity with an EC50 value of 0.34 mM while Compounds 1 and 2 showed scavenging activity of 0.52 and 5.37 mM respectively. The EC50 value for vitamin C is 1.36 mM. The result therefore showed that Compounds 1 and 2 possess better scavenging property than vitamin C and thus may serve as potent antioxidant drugs in oxidative stress management.