Chemical constituents of Coreopsis lanceolata L. and their physiological activities.

Petals from Coreopsis lanceolata L. were extracted in methanol and subjected to solvent-solvent partitioning to yield four fractions: hexane, diethyl ether, ethyl acetate, and aqueous. These fractions were screened using a 1,1-diphenyl-2-picrylhydrazyl radical scavenging assay and an active oxygen inhibition assay. The ethyl acetate extract contained the highest level of active components. Four compounds isolated from this fraction by HPLC were screened for antioxidant activity and anti-allergic activity. Anti-allergic activity was assessed by measuring release of histamine from rat peritoneal mast cells. One compound, termed laceolin, was characterized by spectroscopic analysis, including extensive NMR and mass spectra. This compound had significant radical scavenging activity, with an SC50 (scavenging concentration of 50%) value of 2.6 microg/mL and superoxide dismutase activity of 46.2%.