Sarglamides A–E, Indolidinoid-Monoterpenoid Hybrids with Anti-Neuroinflammatory Activity from a Sarcandra Species

Sarglamides A–E (1−5), representing the first example of heterodimers of a trans-N-cinnamoylindolidinoid and an α-phelladrene derivatives, were isolated from Sarcandra glabra subsp. brachystachys. Particularly, compounds 4 and 5 possess unprecedented cage-like 6/6/5/6/5- and 6/6/6/6/5-fused pentacyclic scaffolds, respectively. Their structures were established by spectroscopic analysis, X-ray crystallography, quantum chemical calculations, and chemical conversions. Plausible biosynthetic pathways of 1−5, involving the co-isolated enantiomers 6a and 6b were proposed. Compounds 3–7 showed inhibitory activity against lipopolysaccharide (LPS) induced inflammation in BV-2 microglial cells.