5-lipoxygenase-inhibitory constituents from Schizandra fructus and Magnolia flos.

In order to establish the antiallergic properties of Schisandra fructus and Magnolia flos, several compounds isolated from these plants were tested for 5-lipoxygenase (5-LOX) inhibitory activity in vitro, for the first time. The compounds including schizandrins, schisandrols, gomisins, fargesin, eudesmin and lirioresinol B dimethyl ether, inhibited 5-LOX-catalysed leukotriene production from A23187-treated rat basophilic leukemia (RBL-1) cells at concentrations of 1-100 microm. In particular, constituents such as schisandrol A and gomisins showed potent inhibitory activity (IC(50)s < 10 microm) on 5-LOX-catalysed leukotriene production, but were much less active on cyclooxygenase-2-catalysed prostaglandin E(2) and inducible nitric oxide-catalysed NO production. These compounds have the potential to be developed as novel antiallergic agents and may contribute to the antiallergic pharmacological use of these plant materials in Chinese medicine. (c) 2009 John Wiley & Sons, Ltd.