Flavonol glycosides and phenylpropanoid glycosides with inhibitory effects on microglial nitric oxide production from Neoshirakia japonica.

Five new flavonol glycosides (1-5), one new phenylpropanoid glycoside (6), and nine known glycosides (7-15) were isolated from the stems and leaves of Neoshirakia japonica. The structures of the new compounds were determined by detailed analysis of spectroscopic data (HRESIMS, 1D and 2D NMR) and acid hydrolysis experiment. The antineuroinflammatory effects of all the isolates were evaluated by inhibiting NO production against LPS-induced BV-2 microglial cells. Compounds 1, 8, and 9 showed more potent inhibitory activities with IC values of 2.7, 5.5, and 4.1 μM, respectively, than that of the positive control minocycline (IC = 15.6 μM), while compounds 7 (IC = 17.0 μM) and 10 (IC = 24.3 μM) also displayed inhibitory activities to a certain degree.