An ether and three ester derivatives of phenylpropanoid from pear (Pyrus pyrifolia Nakai cv. Chuhwangbae) fruit and their radical-scavenging activity

The ethyl acetate-acidic layer obtained after solvent fractionation of Asian pear ( Pyrus pyrifolia Nakai cv. Chuhwangbae) fruit peel methanol extracts was purified by Sephadex LH-20 column chromatography and octadecylsilane-high performance liquid chromatography, and 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity was evaluated. The four isolated compounds were identified as 2- O -( trans - p -coumaroyl) glyceric acid ( 1 ), 2- O -( cis - p -coumaroyl) glyceric acid ( 2 ), guaiacylglycerol-β-ferulic acid ether ( 3 ), and 2- O -( cis -caffeoyl) malic acid ( 4 ), based on the one- and two-dimensional nuclear magnetic resonance spectroscopic data. The isolated compounds 1–4 were identified for the first time from pear. Compound 4 showed higher DPPH radical-scavenging activity than 1–3 .