Isoquinolines from national herb Corydalis tomentella and neuroprotective effect against lipopolysaccharide-induced BV2 microglia cells.

Five new isoquinolines (1-5) were isolated from national herb Corydalis tomentella. Their structures were elucidated by extensive analysis of the 1D and 2D NMR spectra and from the HRESIMS. Absolute configurations of 1-3 were determined by comparing their experimental and computed ECD data. Since plants from Corydalis have been reported to protect against Alzheimer's disease, all compounds were evaluated for their neuroprotective effect against lipopolysaccharide-induced BV2 microglia cells. Compound 2 and 3 showed well anti-neuroinflammatory activity at low concentration (25 µM).