Phytochemical Investigations of Three <i>Rhodocodon</i> (Hyacinthaceae Sensu APG II) Species

The genus <i>Rhodocodon</i> (Hyacinthaceae sensu APG II) is endemic to Madagascar, and its phytochemistry has not been described previously. The phytochemistry of three species in this genus has been investigated, and eight compounds, including three bufadienolides (compounds <b>1</b>, <b>4</b>, and <b>5</b>), a norlignan (<b>2</b>), and four homoisoflavonoids (compounds <b>3</b> and <b>6</b>–<b>8</b>), have been isolated and identified. Compounds <b>1</b>–<b>3</b> and <b>6</b>–<b>8</b> have not been described previously. The COX-2 inhibitory activity of compound <b>6</b> and compound <b>7</b> acetate (compound <b>7A</b>) was investigated on isolated colorectal cancer cells. Compounds <b>6</b> and <b>7A</b> inhibited COX-2 by 10% and 8%, respectively, at a concentration of 12.5 μM compared to 12% for 1 mM aspirin (the positive control)