Isolation and identification of phenolic compounds from Hypericum richeri Vill. and their antioxidant capacity
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The chemical composition and free radical scavenging properties of the MeOH extract of Hypericum richeri and its subsequent CHCl3, n-BuOH, EtOAc and aqueous extracts were investigated. Four quercetin-3-O-glycosides, three myricetin-3-O-glycosides, 3-O- and 5-O-caffeoylquinic acid, quercetin, I3,II8-biapigenin, pseudohypericin and hypericin were identified. The constituents of the extracts were quantified using HPLC-DAD (high-performance liquid chromatography-diode array detector). Isolation of the compounds from n-BuOH and EtOAc extracts was conducted by column chromatography. Antioxidant capacity of the extracts was evaluated by superoxide radical and ABTS root+ scavenging assays and inhibition of lipid peroxidation. The EtOAc extract of H. richeri was the most potent antioxidant in all experiments. Free radical scavenging compounds were identified by HPLC-DPPH root (high-performance liquid chromatography-2,2-diphenyl-1-picrylhydrazyl) post-column derivatisation method, where all phen...olic compounds except I3,II8-biapigenin exhibited radical scavenging properties. This is the first report of the presence of myricetin-3-O-rutinoside, myricetin-3-O-galactoside, myricetin-3-O-glucoside, 5-O-caffeoylquinic acid and I3,II8-biapigenin in H. richeri.
Keywords:Hypericum richeri / phenolics / HPLC-DAD / on-line HPLC-DPPH / antioxidant capacity
Source:Natural Product Research, 2011, 25, 3, 175-187
- Taylor & Francis Ltd, Abingdon