Chrydintins A and B, two new sesquiterpenoids from <i>Chrysanthemum indicum</i> with cardioprotective activities

Chrydintins A (<b>1</b>) and B (<b>2</b>), two new sesquiterpenoids were isolated from <i>Chrysanthemum indicum</i>., together with four known ones identified as 9-hydroxyeudesma-4,7(11)-dien-6-one (<b>3</b>), (7<i>S</i>,9<i>S</i>,10<i>S</i>)-9-hydroxy-11-methoxyeudesm-4-en-6-one (<b>4</b>), curcumenone (<b>5</b>), and polydactin B (<b>6</b>), respectively. The structures of isolated compounds were determined by HR-ESI-MS, NMR analysis, and quantum chemical calculation. The <i>in vitro</i> cardioprotective activities of all compounds were studied on H₂O₂-injured H9C2 cells using MTT assay method. Compound <b>5</b> exhibited considerable protective effect with cell viability at 81.45 ± 1.07%.