Undescribed\nAmaryllidaceae Alkaloids from <i>Zephyranthes citrina</i> and Their Cytotoxicity

This phytochemical study presents\nthe isolation of eight\nalkaloids\nfrom <i>Zephyranthes citrina</i> Baker. The structures of\nthe new alkaloids, zephycitrine (<b>1</b>) and 6-oxonarcissidine\n(<b>2</b>), were established by analysis of spectroscopic and\nspectrometric data. Processing the EtOH extract under acid–base\nconditions yielded the unreported isolation artifacts <b>3</b> and <b>4</b>. This work also provides analytical data for\nalkaloids not properly described in the literature (<b>5</b> and <b>6</b>). The hippeastidine/zephyranine scaffolds in\nderivatives <b>3</b>, <b>4</b>, and <b>8</b>–<b>10</b> are also thoroughly discussed. Furthermore, a cytotoxicity\nscreening of 25 Amaryllidaceae alkaloids isolated from <i>Z.\ncitrina</i> was performed. Only the known alkaloids haemanthamine\n (<b>12</b>), haemanthidine (<b>13</b>), and lycorine\n(<b>27</b>) showed significant cell growth inhibition.