Anew tetrahydrofuran-type lignan from leaves of Magnolia denudata / 中草药

ABSTRACT

Objective: To study the lignans in the leaves of Magnolia denudata. Methods: The constituents were separated and purified by silica gel, Sephadex LH-20 and semi-preparative HPLC. The structures were elucidated on the basis of spectroscopic data analysis. All compounds were evaluated for their inhibitory activity against LPS-activated NO production in RAW 264.7 cell model in vitro. Results: Two tetrahydrofuran-type lignans and three dihydrobenzofuran-type lignans were isolated from 95% ethanol extract of M. denudate. Their structures were identified as (7S,7'R,8S,8'S)-3,4,5-trimethoxy-3',4'-methylenedioxy-7,7'-epoxylignan (1), veraguensin (2), liliflol A (3), liliflol B (4) and 5-methoxyliliflol B (5). Conclusion: Compound 1 is a new compound and named as magnodatin A. Compound 5 is a new natural product. The 13C-NMR spectroscopic data of compounds 3-5 are reported for the first time. Compound 5 exhibited weak inhibitory effect on NO production in LPS-induced macrophages with a inhibiton rate of 48.7% at 50 μmol/L.