The phytochemical investigation of the roots of Chloranthus henryi
Hemsl. var. hupehensis (Pamp.) K. F. Wu led to the isolation and
identification of 23 structurally diverse sesquiterpenes and their
dimer, including a new eudesmane sesquiterpenoid dimer, nineteen new
sesquiterpenoids and three known sesquiterpenoids. Among the isolates, 1
was a rare sesquiterpenoid dimer formed by assembling two highly
rearranged eudesmane-type sesquiterpenes through a unique oxygen bridge
(C-11–O–C-8′). It is worth noting that rearranged eudesmane type
sesquiterpenoid dimers containing an oxygen bridge are rarely isolated
from nature. (+)-2 and (−)-2 were a pair of new skeleton
sesquiterpenoids with a remarkable 6/6/5 tricyclic ring framework
including one γ-lactone ring and the bicyclo[3.3.1]nonane core.
Their structures and absolute configurations were determined by
spectroscopic analysis, single-crystal X-ray diffraction analysis, and
quantum chemical calculation. Moreover, all the isolated compounds were
evaluated for their potential anti-inflammatory activity using an
LPS-induced BV-2 cell microglial. Among them, 18 suppressed TNF-α and
IL-1β expression with EC50 values of 6.81 µM and 2.76 µM, respectively,
indicating its excellent efficacy in inhibiting inflammatory factors
production. In subsequent mechanism studies, compounds 3, 17, and 18
could reduce the production of IL-1β and TNF-α by inhibiting the
activation of IKBα/p65 pathway.