Two new flavonol glycosides from <i>Dimocarpus longan</i> leaves

<div><p>From the extracts of <i>Dimocarpus longan</i> Lour leaves, 2 unusual flavonol glycosides, quercetin 3-<i>O</i>-(3″-<i>O</i>-2‴-methyl-2‴-hydroxylethyl)-β-d-xyloside (<b>1</b>) and quercetin 3-<i>O</i>-(3″-<i>O</i>-2‴-methyl-2‴-hydroxylethyl)-α-l-rhamnopyranoside (<b>2</b>), as well as 10 known compounds including 2 flavonol glycosides, afzelin (<b>3</b>) and kaempferol-3-<i>O</i>-α-l-rhamnopyranoside (<b>4</b>), 2 flavans, ( − )-epicatechin (<b>5</b>) and proanthocyanidin A-2 (<b>6</b>), 3 triterpenoids, friedelin (<b>7</b>), epifriedelanol (<b>8</b>) and β-amyrin (<b>9</b>), a peptide, <i>N</i>-benzoylphenylalanyl-<i>N</i>-benzoylphenylalaninate (<b>10</b>), and 2 sterols, β-sitosterol (<b>11</b>) and daucosterol (<b>12</b>) were isolated and identified by using combination of mass spectrometry and various 1D and 2D NMR techniques. This is the first report of flavonoid glycosides possessing a 2-methyl-2-hydroxylethoxyl group in sugar moiety from <i>D. longan</i>.</p>