Polyhydric Stigmastane-Type Steroids Derivative from Vernonia amygdalina and Their Anti-Neuroinflammatory Activity

Vernonia amygdalina Del. is a traditional medicinal plant and vegetable originating from tropical Africa. The phytochemical investigation of V. amygdalina led to eight undescribed polyhydric stigmastane-type steroids, vernonin M–T (1–8). Their gross structures and stereochemistry were elucidated by HR-ESI-MS, 1D and 2D NMR spectra, X-ray diffraction, quantum chemical computation of the ECD spectrum, and the in situ dimolybdenum CD method. The anti-neuroinflammatory activity of the isolated compounds was performed in BV-2 microglia cells. As a result, compound 1 displayed a notable anti-neuroinflammatory effect via suppressing the LPS-induced IκB degradation and restricting the activation of the PI3K/AKT and p38 MAPK pathways.