A pair of enantiomeric sesquiterpenoids with neuroprotective effects from Chloranthus henryi

An ethanol extract of Chloranthus henryi (Chloranthaceae) was subjected to various chromatographic procedures including silica gel column chromatography, MCI column chromatography, Sephadex LH-20 column chromatography, and preparative HPLC. Five purified sesquiterpenes analyzed by spectroscopic analyses (MS, IR, NMR) and single crystal X-ray diffraction were elucidated as (1S,6S,8R)-8-ethoxychlomultin C (1a), (1R,6R,8S)-8-ethoxychlomultin C (1b), (+)-phaeocaulin D (2), atractylenolide Ⅰ (3), and 8-β-ethoxyasterolid (4). Compounds 1a and 1b were a new pair of sesquiterpene enantiomers and compounds 2-4 were isolated from this plant for the first time. Compounds 1a, 1b, 2 and 3 increased cell viability in H₂O₂-treated PC12 cells from (43.41±1.59)% to (61.71±7.56)%, (66.05±5.61)%, (74.34±3.32)% and (69.58±5.02)% at 10 μmol·L^-1, respectively.