Three new pterosins from Pteris semipinnata .

Three new pterosins, named as semipterosin A ( 1 ), B ( 2 ) and C ( 3 ), together with 11 known pterosins ( 4 - 14 ), were isolated from the aerial parts of Pteris semipinnata . Their structures were elucidated by HRESI-MS, NMR spectral data, CD and literature comparisons. Three new pterosins were assessed for their anti-inflammatory activity. Compounds 1 - 3 inhibited the NF- k B induction by 40.7%, 61.9% and 34.0%, respectively. This is the first report of the isolation of compounds 6 - 14 from this plant.