Neolignans from the Fruits of Magnolia obovata and Their Inhibition Effect on NO Production in LPS-Induced RAW 264.7 Cells.

Three new neolignans, named 9-methoxyobovatol (6), magnobovatol (7), and 2-hydroxyobovaaldehyde (9), along with six known ones, magnolol (1), honokiol (2), isomagnolol (3), obovatol (4), obovatal (5), and obovaaldehyde (8), were isolated from the fruits of Magnolia obovata using silica gel and ODS column chromatography. From the results of spectroscopic data including EIMS, IR, ¹H- and ¹³C-NMR, DEPT, and 2D-NMR (gCOSY, gHSQC, gHMBC), the chemical structures were determined. All isolated compounds were evaluated for inhibition activity on nitric oxide production in LPS-induced RAW 264.7 cells, and compounds 1-4, 6, 7, and 9 showed significant activity with IC₅₀ values of 15.8 ± 0.3, 3.3 ± 1.2, 14.1 ± 0.9, 6.2 ± 1.2, 14.8 ± 2.3, 14.2 ± 1.2, and 14.8 ± 3.2 µM, respectively, without any visible toxic effect. [ABSTRACT FROM AUTHOR]