ABSTRACT Four novel compounds ( 1 – 4 ) and 22 known compounds ( 5 – 26 ) were obtained from the roots of Arnebia euchroma (Royle) Johnst. The four novel compounds are three quinones named euchronins K‐M ( 1 – 3 ), and one arnebinol compound, named arnebinol E ( 4 ). The molecular architecture of the novel compounds was unambiguously established through systematic spectral characterization, including high‐resolution electrospray ionization mass spectrometry, ultraviolet, infrared, one‐ and two‐dimensional nuclear magnetic resonance experiments, and electronic circular dichroism for stereochemical verification. Cellular bioactivity profiling of these compounds was evaluated by us in this study. In vitro cell viability screening assays, the results showed that the compounds 1 , 2 , 4 , 10 , 11 , 15 , 19 , 20 , and 26 exhibited strong neuroprotective activity, with 50% effective concentration values ranging from 3.66 to 19.23 µM.
Wu et al. (Sun,) studied this question.