Bioactive Lignan Constituents from the Twigs of Lindera glauca

A bioassay-guided fractionation and chemical investigation of the MeOH extract from the twigs of Lindera glauca (SIEB. et ZUCC.) BLUME resulted in the isolation and identification of six lignans (1-6) including three new lignan derivatives, named linderuca A (1), B (2), and C (3). The structures of the new compounds (1-3) were determined on the basis of spectroscopic analyses, including two dimensional NMR and circular dichroism (CD) spectroscopy studies. The cytotoxic activities of the isolates (1-6) were evaluated by determining their inhibitory effects on human tumor cell lines. Compounds 1-5 showed antiproliferative activities against A549, SK-OV-3, SK-MEL-2, and HCT-15 cell lines with IC50 values of 7.79-29.42 mu M. Based on the understanding that inflammation is a crucial cause of tumor progression, we also investigated the anti-inflammatory activities of the isolates (1-6) in the lipopolysaccharide-stimulated murine microglia BV-2 cell line by measuring nitric oxide (NO) levels. The new lignans (1-3) significantly inhibited NO production with IC50 values of 12.10, 9.48, and 9.87 mu M, respectively, without cytotoxicity.