Anti-inflammatory neolignans from the roots of Magnolia officinalis

Nine neolignan derivatives (1-9) were characterized from the roots of Magnolia officinalis, and their structures were elucidated based on spectroscopic and physicochemical analyses. Among them, houpulins E (1) and M (9) possess novel homo- and trinor-neolignan skeletons. In addition, 15 known compounds (10-24) were identified by comparison of their spectroscopic and physical data with those reported in the literature. Some of the purified constituents were examined for anti-inflammatory activity and, among the tested compounds, houpulins G (3), I (5), J (6), and 2,2'-dihydroxy-3-methoxy-5,5'-di-(2-propenylbiphenyl) (19) significantly inhibited superoxide anion generation and elastase release with IC50 values ranging from 3.54 to 5.48 μM and 2.16 to 3.39 μM, respectively. Therefore, these neolignan derivatives have tremendous potential to be explored as anti-inflammatory agents.