Chrydintins A and B, two new sesquiterpenoids from Chrysanthemum indicum with cardioprotective activities

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