<p>A new chromanone derivative, namely caloinophyllin A (<b>1</b>), along with eight known compounds (<b>2</b>–<b>9</b>), nobiletin (<b>2</b>), pentamethylquercetin (<b>3</b>), 3,5,7,4′-tetramethoxyflavone (<b>4</b>), 5,7,4′-trimethoxyflavone (<b>5</b>), 1,5-dihydroxyxanthone (<b>6</b>), 1,8-dimethoxy-2-hydroxyxanthone (<b>7</b>), 1,6-dihydroxy-7-methoxyxanthone (<b>8</b>) and 4-methoxycaffeic acid (<b>9</b>) were isolated from the roots of <i>Calophyllum inophyllum</i>. The structures of all the isolated compounds (<b>1</b>–<b>9</b>) were fully characterised using spectroscopic data, as well as comparison with the previous literature data. In addition, the quantum chemical calculation has been used to confirm the conformation of <b>1</b>. Moreover, all isolated compounds were assessed for their <i>in vitro</i> cytotoxicity against five human cancer cell lines.</p
