Flavonol glycosides from the aerial parts of Aceriphyllum rossii and their antioxidant activities.Arch Pharm Res. 2004 Apr; 27(4):390-5.AP
The methanol extract obtained from the aerial parts of Aceriphyllum rossii (Saxifragaceae) was fractionated into ethyl acetate (EtOAc), n-BuOH and H2O layers through solvent fractionation. Repeated silica gel column chromatography of EtOAc and n-BuOH layers afforded six flavonol glycosides. They were identified as kaempferol 3-O-beta-D-glucopyranoside (astragalin, 1), quercetin 3-O-beta-D-glucopyranoside (isoquercitrin, 2), kaempferol 3-O-alpha-L-rhamnopyranosyl (1-->6)-beta-D-glucopyranoside (3), quercetin 3-O-alpha-L-rhamnopyranosyl (1-->6)-beta-D-glucopyranoside (rutin, 4), kaempferol 3-O-[alpha-L-rhamnopyranosyl (1-->4)-alpha-L-rhamnopyranosyl (1-->6)-beta-D-glucopyranoside] (5) and quercetin 3-O-[alpha-L-rhamnopyranosyl (1-->4)-alpha-L-rhamnopyranosyl (1-->6)-beta-D-glucopyranoside] (6) on the basis of several spectral data. The antioxidant activity of the six compounds was investigated using two free radicals such as the ABTS free radical and superoxide anion radical. Compound 1 exhibited the highest antioxidant activity in the ABTS [2,2-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid)] radical scavenging method. 100 mg/L of compound 1 was equivalent to 72.1+/-1.4 mg/L of vitamin C, and those of compounds 3 and 5 were equivalent to 62.7+/-0.5 mg/L and 54.3+/-1.3 mg/L of vitamin C, respectively. And in the superoxide anion radical scavenging method, compound 5 exhibited the highest activity with an IC50 value of 17.6+/-0.3 microM. In addition, some physical and spectral data of the flavonoids were confirmed.