Biphenyl-type neolignans from Magnolia officinalis and their anti-inflammatory activities.

Reactive oxygen species (ROS) and granule proteases produced by human neutrophils contribute to the pathogenesis of inflammatory diseases. The MeOH extract of the stem bark of Magnolia officinalis showed potent inhibitory effects on superoxide anion generation and elastase release by human neutrophils in response to formyl-L-methionyl-L-leucyl-L-phenylalanine/cytochalasin B (fMLP/CB). Five biphenyl-type neolignan derivatives, 5-allyl-5'-(1″-hydroxyallyloxy)biphenyl-2,2'-diol, 5,5'-diallyl-2'-(allyloxy)biphenyl-2-ol, 5,5'-diallyl-2'-(3-methylbut-2-enyloxy)biphenyl-2-ol, (E)-5-allyl-3'-(prop-1-enyl)biphenyl-2,4'-diol, and 4-allyl-2-(2'-methylbenzofuran-5'-yl)phenol, have been isolated from the stem bark of M. officinalis, together with 12 known compounds. Several exhibited inhibition (IC₅₀) values ≤10.7 μM) of superoxide anion generation by human neutrophils in response to fMLP/CB. Others inhibited fMLP/CB-induced elastase release with IC₅₀) values ≤8.76 μM.