Wunorlactones A-G, seven undescribed 7/8/5 and 7/8/3 carbon skeleton schinortriterpenoids from the stems and leaves of Schisandra chinensis, and their neuroprotective activities.

Schisandra chinensis is an important traditional Chinese medicine and its main bioactive components are lignans and schinortriterpenoids (SNTs). The aim of this study was to explore the biologically rich SNTs from the stem and leaves of S. chinensis (SCSL). Here, seven previously undescribed 7/8/5 and 7/8/3 carbon skeleton SNTs (1-7) were reported. Their structures were determined by NMR, UV, MS, ECD, and X-ray diffraction analyses, and the neuroprotective activities of these compounds on corticosterone-induced PC12 cell injury were evaluated. The results showed that 1, 5, and 7 (25 μM) had neuroprotective effects, and the cell viability was increased by 20.07%, 14.24%, and 15.14% (positive control: 30.64%), respectively. These findings increased the number of described SNTs in SCSL, and the neuroprotective activities of all compounds indicated their potential application in neurodegenerative diseases.