HPLC-PDA-MS and NMR characterization of a hydroalcoholic extract of citrus aurantium L. Var. amara Peel with antiedematogenic activity

The phytochemical profile of a hydroalcoholic extract of Citrus aurantium var. amara L. peel, used as herbal medicine, was characterized by HPLC-PDA-MS. Two di-C-glycosyl flavones (vincenin II and diosmetin 6,8-di-C-glucoside), a series of flavones (luteolin 7-O-neohesperidoside, rhoifolin, and neodiosmin), and flavanone (neoeriocitrin, naringin, and neohesperidin) 7-O-neohesperidosides and two methoxyflavones (nobiletin and tangeretin), commonly present in Citrus, were identified. Furthermore, brutieridin and melitidin, two 3-hydroxy-3-methylglutaryl flavanone glycosides, were also characterized along with rhoifolin 4′-glucoside and three coumarins (8,3′-β-d- glucopyranosyloxy-2′-hydroxy-3′-methylbutyl-7-methoxycoumarin, merazin hydrate, and isomerazin). A preparative isolation procedure followed by NMR spectroscopy confirmed the proposed structures of the major flavonoids and identified the coumarins. The phenolic content was found to be 14.8 mg mL -1, and naringin and neohesperidin were the compounds present in the highest concentration (3.6 and 2.6 mg mL-1). The extract of C. aurantium peel inhibited significantly (p < 0.05) both histamine- and dextran-induced edema in rats in a concentration-dependent manner (IC 50 = 119.6 and 118.3 mg kg-1, respectively), providing evidence for the therapeutic use of C. aurantium var. amara peel. © 2012 American Chemical Society