Limonoids from the Leaves and Twigs of <i>Walsura yunnanensis</i>

Nine new cedrelone limonoids, namely, walsuranolide B (<b>1</b>), 11β-hydroxy-23-<i>O</i>-methylwalsuranolide (<b>2</b>), yunnanolide A (<b>3</b>), yunnanol A (<b>4</b>), 11β-hydroxyisowalsuranolide (<b>5</b>), 11β-hydroxy-1,2-dihydroisowalsuranolide (<b>6</b>), 1α,11β-dihydroxy-1,2-dihydroisowalsuranolide (<b>7</b>), 11β-hydroxy-1α-methoxy-1,2-dihydroisowalsuranolide (<b>8</b>), and yunnanolide B (<b>9</b>), together with a new cycloartane triterpenoid, (24<i>S</i>*,25<i>R</i>*)-cycloartane<i>-</i>3β<i>,</i>24,25,26<i>-</i>tetrol (<b>10</b>), were isolated from the leaves and twigs of <i>Walsura yunnanensis</i>. Their structures were elucidated on the basis of spectroscopic analysis and by comparison with literature data. Compounds <b>3</b> and <b>5</b> exhibited potent cytotoxicity against five human tumor cell lines with IC₅₀ values in the range 2.2–4.2 μM