Pyrrolizidine alkaloids, glycosylated flavonols and phenolic acid derivatives from the aerial parts of <i>Pardoglossum cheirifolium</i> (L.) Barbier &amp; Mathez

Abstract

In the present study, we aimed to report the identified chemical composition of methanol and <i>n</i>-butanol extracts obtained from the aerial parts of the Algerian <i>Pardoglossum cheirifolium</i> (L.) Barbier & Mathez. Heliosupine N-oxide (<b>1</b>) was isolated from the <i>n</i>-butanol extract and structurally characterised by extensive NMR and ESI-MS/MS data. LC-DAD-ESI/MS analysis on methanol extract aimed at determining pyrrolizidine alkaloids of which the <i>Pardoglossum</i> genus is a rich source, led to the proposed identification of lycopsamine N-oxide (<b>2</b>), echinatine N-oxide (<b>3</b>), dihydrolycopsamine (<b>4</b>), dihydroechinatine (<b>5</b>), 7-acetyl dihydrolycopsamine (<b>6</b>), 7-acetyllycopsamine N-oxide (<b>7</b>), 3'-acetylviridiflorine (<b>8</b>), vulgarine (<b>10</b>), and heliosupine (<b>16</b>). The glycosylated flavonols quercetin 3-<i>O</i>-rhamnopyranoside-(1→2)-glucopyranosyl-(1→6)-rhamnopyranoside (<b>9</b>), kaempferol 3-<i>O</i>-L-rhamnopyranosyl-(1→2)-rhamnopyranosyl-(1→6)-glucopyranoside (<b>11</b>), rutin (<b>12</b>), kaempferol 3-<i>O</i>-rutinoside (<b>13</b>), in addition to 3,4,5-trihydroxycinnamic acid glucopyranoside (<b>14</b>) and 3,5-dihydroxycinnamic acid-<i>O</i>-diglucopyranoside (<b>15</b>), were also identified. For the first time, we report the known metabolites <b>2 </b>-<b> 11</b> and <b>13 </b>-<b> 15</b> in the studied plant, both reported as <i>Pardoglossum cheirifolium</i> and <i>Cynoglossum cheirifolium.</i>