Two new eudesmane sesquiterpenoids with neuroprotective activity from Pogostemon cablin.

Two new eudesmane sesquiterpenoids [(−)-(1 R ,5 S ,6 R ,8 S)−1-hydroxy- nor -eudesm-11-ene-2-one (1) and (−)-(1 S ,5 S ,6 R ,8 R)−6-hydroxyeudesm-11-ene-2-one (2)] were isolated from the aerial parts of Pogostemon cablin. Compound 1 is an unusual 1- nor -eudesmane, and its skeleton structure is similar to that of compound 2. The molecular structures and absolute conformations of the two new sesquiterpenoids were determined by NMR spectroscopy, X-ray diffraction analysis, NMR data calculations and electronic circular dichroism (ECD) calculations. The neuroprotective activity of the isolates in an H 2 O 2 -induced PC12 cell model was also assessed, and the results show that both compounds exhibit good neuroprotective effects. [Display omitted] • Two new eudesmane sesquiterpenoids were isolated from Pogostemon cablin. • Their absolute configurations were elucidated by NMR data, X-ray diffraction, NMR data calculations and ECD calculations. • Compounds 1 and 2 may play a role in reducing the cytotoxicity of H 2 O 2 on PC12 cells. [ABSTRACT FROM AUTHOR]