Lignans from the rhizomes of Iris tectorum.

Chemical examination of the ethanol extract of rhizomes of Iris tectorum led to the isolation and characterization of three new lignans, (7 R ,7′ R ,8 S ,8′ S )-5′-methoxy-neo-olivil (1a), (7 S ,7′ S ,8 R ,8′ R ) -5′-methoxy-neo-olivil (1b), (7 S ,7′ R ,8 S ,8′ S )-neo-olivil (2a), (7 R ,7′ S ,8 R ,8′ R )-neo-olivil (2b), (7 R ,7′ R ,8 S ,8′ S ,7′′ S ,8′′ S )- threo -neo-olivil-4′-O-8-guaiacylglycerol ether (3), together with six known ones (4–9). Among them, compounds 1 and 2 were found to be racemic mixtures, respectively, which were verified by chiral HPLC analysis, compound 3 was a new sesquineolignan. The structures were elucidated on the basis of extensive spectroscopic analysis. To our knowledge, this is the first report of lignan constituents isolated from I. tectorum . All compounds were evaluated for their cytotoxicity against five human tumor cell lines and none of them displayed significant toxicity in tested cell lines at a concentration of 10 μM. [ABSTRACT FROM AUTHOR]