New lipoxygenase inhibitors isolated from Chinese plants. Development of new anti-allergic drugs

Some natural compounds isolated from Chinese plants were found to have strong inhibitory activity for 5-lipoxygenase and were thus able to inhibit leucotriene synthesis. Among these compounds, caffeic acid was selected for study; more than 100 of its derivatives were synthesized and tested for 5-lipoxygenase inhibitory activity. Two derivatives, TMK-919 and TMK-920, proved to be 100 times more potent than the parent compound and were able to inhibit the homologous PCA reaction significantly in rats at a dose of 10 mg/kg, i.v.