OBJECTIVE: To study the flavonoids and their antioxidant activities of Artemisia annua. METHODS: Isolation and purification were carried out by silica gel and Sephadex LH-20 column chromatographies. Compounds were identified by physicochemical properties and spectral analysis, then their antioxidant activities were evaluated by ORAC assay. RESULTS: Five flavonoids were isolated from the plant. Their structures were identified as 5-hydroxy-3,7,4'-trimethoxyflavone(1), 5-hydroxy-6,7,3',4'-tetramethoxyflavonol(2), blumeatin(3), 5, 4'-dihydroxy-3,7,3'-trimethoxyflavone(4) and quercetin(5), respectively. Compounds 1-5 could slow up the attenuation rate of the fluorescence induced by AAPH. CONCLUSION: Compounds 1-3 are isolated from the plant for the first time. Compounds 1-5 all possess the potential antioxidant activities.
OBJECTIVE: To study the flavonoids and their antioxidant activities of Artemisia annua. METHODS: Isolation and purification were carried out by silica gel and Sephadex LH-20 column chromatographies. Compounds were identified by physicochemical properties and spectral analysis, then their antioxidant activities were evaluated by ORAC assay. RESULTS: Five flavonoids were isolated from the plant. Their structures were identified as 5-hydroxy-3,7,4'-trimethoxyflavone(1), 5-hydroxy-6,7,3',4'-tetramethoxyflavonol(2), blumeatin(3), 5, 4'-dihydroxy-3,7,3'-trimethoxyflavone(4) and quercetin(5), respectively. Compounds 1-5 could slow up the attenuation rate of the fluorescence induced by AAPH. CONCLUSION: Compounds 1-3 are isolated from the plant for the first time. Compounds 1-5 all possess the potential antioxidant activities.