Noralashinols D-F, New Norlignans from Syringa pinnatifolia and its Anti-Inflammation in BV2 Cells.

Four new norlignans, noralashinols D-F (1a/b-3), and two known analogues (4 and 5) were isolated from the peeled stems of Syringa pinnatifolia Hemsl. The structures were elucidated by analysis of spectroscopic data, such as IR, HR-ESI-MS, 1D and 2D NMR, and ECD. All compounds were evaluated for anti-inflammatory activities against NO production induced by LPS in BV2 microglia cells. Compounds 1b and 2 exhibited moderate activities with IC50 values of 32.39±9.1 and 47.83±10.44 µM, respectively, compared with positive control indomethacin (IC50=21.62 µM). It is worth to note that 1, 3, and 4 have a distinctive woody fragrance.