Diversity of sesquiterpenoids from Stellera chamaejasme with neuroprotective effects

Chromatographic fractionation of the 95% EtOH extract of the roots of Stellera chamaejasme yielded 20 sesqui-terpenoids of four different types, guaiane-, carotane-, sesquicarane-, and alpiniane-types. Among them, ses-quistrachanoids A-F were previously undescribed ones, whose structures including absolute configurations were elucidated by spectroscopic methods, the Mo2(OAc)4-induced ECD experiment, and analysis of experimental and calculated 1D NMR and ECD data. Sesquistrachanoid A is a 2,3-seco-guaiane-type sesquiterpenoid with a alpha-pyrone core and sesquistrachanoid B is the first example of 8,9-seco-guaiane-type sesquiterpenoid featured with an 1,8-delta-lactone core. Sesquistrachanoid C is a guaiane sesquiterpenoid characterized by a peroxide bridge be-tween C-8 and C-10. All sesquiterpenoids were evaluated for their neuroprotective effects on cell damage induced by sodium nitroprusside in PC-12 cells. The bioassay results showed that six compounds at 10 mu M could restore the cell viability, being comparable to that of the positive control edaravone. The mechanistic study on the most pronounced activity compound, stelleraguaianone B, demonstrated that it played a neuroprotective role by promoting the mRNA expression of antioxidant enzymes to reduce oxidative stress.

Automated summary

In this study, 20 sesquiterpenoids of four different types were isolated from the 95% ethanol extract of Stellera chamaejasme roots, including six previously undescribed ones. The structures and absolute configurations of these compounds were elucidated, and their neuroprotective effects on cell damage were evaluated.