Sweritranslactone D, a hepatoprotective novel secoiridoid dimer with tetracyclic lactone skeleton from heat-transformed swertiamarin

Swertia mileensis, known as Qing-Ye-Dan (QYD), has been documented in Chinese Pharmacopoeia to cure hepatitis. Interestingly, its announced main active component, swertiamarin, could not be detected the decoction, which indicated that efficacy of QYD might attributed heat-transformed products swertiamarin (HTPS). Further investigation on HTPS led isolation sweritranslactone D (1), a novel secoiridoid dimer possessing tetracyclic lactone skeleton, with better hepatoprotective activity than N-acetyl-L-cysteine vitro.