Hedychins E and F: Labdane-Type Norditerpenoids with Anti-Inflammatory Activity from the Rhizomes of <i>Hedychium forrestii</i>

Hedychin E (1), a novel labdane-type norditerpenoid, and hedychin F (2), a new labdane-type dinorditerpenoid, were isolated from the rhizomes of Hedychium forrestii. Their structures were determined through a combination of spectroscopic analysis and X-ray single-crystal diffractions. Hedychin E (1) is an unprecedented 6-norditerpenoid with a fused tetrahydrofuran-lactone motif, and a reasonable biosynthetic pathway for 1 was proposed. Compound 2 showed a significant anti-inflammatory effect against LPS-induced NO production in macrophage RAW264.7 cells with an IC50 value of 21.0 μM