One new acetogenin, 6-hydroxy-8-pentadecyloxocane-2,7-dione ( 1), and four new prenylated flavonoids, 4''a,5'',6'',7'',8'',8''a-hexahydro-5,3',4'-trihydroxy-5'',5'',8''a-trimethyl-4 H-chromeno[2'',3'':7,6]flavone ( 2), 4''a,5'',6'',7'',8'',8''a-hexahydro-5,3',4',-trihydroxy-5'',5'',8''a-trimethyl-4 H-chromeno[2'',3'':7,8]flavone ( 3), 2-(3,4-dihydroxyphenyl)-6-((2,2-dimethyl-6-methylenecyclohexyl)methyl)-5,7-dihydroxy-chroman-4-one ( 4), and 2-(3,4-dihydroxy-2-[(2,6,6-trimethylcyclohex-2-enyl)methyl]phenyl)-3,5,7-trihydroxy-4 H-chromen-4-one ( 5), together with six known compounds, were isolated and purified from the rhizomes of Helminthostachys zeylanica by column chromatography and high performance liquid chromatography (HPLC) via bioactivity-guided fractionation isolation. The structures of the new isolates were elucidated by spectroscopic methods. Compounds 1, 3, and 5 showed inhibitory activities on either superoxide anion generation or elastase release by human neutrophils in response to formyl-L-methionyl-L-leucyl-L-phenylalanine/cytochalasin B (FMLP/CB).
(c) Georg Thieme Verlag KG Stuttgart . New York.