Bioactive isoquinoline alkaloids from <i>Cissampelos pareira</i><sup>†</sup>

<p>The phytochemical and biological investigation of <i>Cissampelos pareira</i> leads to the isolation of one new isoquinoline alkaloid (<b>7</b>) along with six known isoquinoline alkaloids, namely, magnoflorine (<b>1</b>), magnocurarine (<b>2</b>), cissamine (<b>3</b>), curine (<b>4</b>), hayatinine (<b>5</b>) and cycleanine (<b>6</b>). Magnoflorine (<b>1</b>) and magnocurarine (<b>2</b>) were isolated for the first time from <i>C. pareira.</i> A new, rapid, simple and sensitive UPLC method was developed for simultaneous quantification of five pure compounds (<b>1</b>–<b>5</b>). Seasonal variation study revealed higher content of these compounds during the rainy season. The chloroform (CPCF) and <i>n</i>-butanol (CPBF) fractions showed cytotoxic efficacy against KB cells. Among pure compounds, hayatinine (<b>5</b>) was found to be most active against KB and A549, while, cycleanine (<b>6</b>) against KB cells.</p>