Cnidicin, a coumarin, from the root of Angelica koreana, inhibits the degranulation of mast cell and the NO generation in RAW 264.7 cells.

Cnidicin (1) and five related coumarins were isolated from the root extract of Angelica koreana (Umbelliferae) as active principles responsible for the inhibitory effect on the degranulation process of cultured mast cells. Cnidicin (1) demonstrated a significant inhibition upon the release of beta-hexosaminidase from the cultured RBL-2H3 cells in a dose dependent manner (IC50 value, 25 microM) and upon the nitric oxide production from the activated RAW264.7 cells (IC50 value, 7.5 microM). In agreement with this, cnidicin inhibited the expression of nitric oxide synthase in RAW264.7 cells.