Illihenin A: An Antiviral Sesquiterpenoid with a Cage-like Tricyclo[6.2.2.0^1,5]dodecane Skeleton from <i>Illicium henryi</i>

Abstract

Illihenin A (<b>1</b>), a novel sesquiterpenoid, was isolated from the roots of <i>Illicium henryi</i>. The structure was determined by spectroscopic analyses, ECD calculation, and single-crystal X-ray diffraction. Compound <b>1</b> represents a class of novel 5/7/6 tricyclic sesquiterpenoids featuring a rare cage-like tricyclo[6.2.2.0^1,5]dodecane core. A plausible biosynthetic pathway of <b>1</b> by rearrangement of <i>allo</i>-cedrane is proposed. Additionally, <b>1</b> showed potent antiviral activity against coxsackievirus B3 with an IC₅₀ value of 2.87 μM.