Anti-inflammatory and spasmolytic activity of extracts from Droserae herba.

An ethanolic extract of Drosera madagascariensis inhibited human neutrophil elastase with an IC50 of 9.4 microg/ml. The naphthoquinones present in the extract were not responsible for this effect, but flavonoids like quercetin (IC50 0.8 microg/ml), hyperoside (IC50 0.15 microg/ml) and isoquercitrin (IC50 0.7 microg/ml) contributed to inhibition of the enzyme. In guinea-pig ileum the extract (0.5-1 mg/ml) induced a spasmolytic effect via affecting cholinergic M3 receptors and histamine H1 receptors, respectively. At contractile prostanoid receptors of guinea-pig trachea the Drosera extract was not effective.