Cruzain Inhibitory Activity of Leaf Essential Oils of Neotropical Lauraceae and Essential Oil Components

Abstract

The leaf essential oils of twenty-three species of Lauraceae from Monteverde, Costa Rica, have been screened for inhibition of the cysteine protease cruzain. Of these, nine showed promising cruzain inhibitory activity (IC 50 < 100 μg/mL), six showed marginal activity (IC 50 , 100–500 μg/mL), and eight were inactive (IC 50 > 500 μg/mL). The cruzain inhibitory activities of the essential oils can be attributed to active sesquiterpenoid components as well as synergistic effects between two or more components. The sesquiterpenes α-copaene, β-caryophyllene, α-humulene, and germacrene D are active (IC 50 ~5–30 μg/mL) alone, but also show increased activity in combination with other essential oil components.