Euphormins A and B, New Pyranocoumarin Derivatives from Euphorbia formosana Hayata, and Their Anti-Inflammatory Activity

Euphormin-A (1) and euphormin-B (2), two new pyranocoumarin derivatives, and forty known compounds (3–42) were isolated from Euphorbia formosana Hayata (Euphorbiaceae). The chemical structures of all compounds were established based on spectroscopic analyses. Several isolates were evaluated for their anti-inflammatory activity. Compounds 1, 2, 10, 18, 25, and 33 significantly inhibited against superoxide anion generation and elastase release by human neutrophils in response to formyl-L-methionyl-L-leucyl-L-phenylalanine/cytochalasin B (fMLP/CB). Furthermore, compounds 25 and 33 displayed the most potent effects with IC(50) values of 0.68 ± 0.18 and 1.39 ± 0.12 µM, respectively, against superoxide anion generation when compared with the positive control (2.01 ± 0.06 µM).