Four New Limonoids from the Barks of Toona ciliata.

ABSTRACT

Four new limonoids, toonayunnanaes F - I (1 - 4), and six known compounds (5 - 10) were isolated from the barks of Toona ciliata. Their structures were elucidated by thoroughly analyzing of NMR and HRMS data, and single-crystal X-ray diffraction of 1. The oxetane ring moiety in 1 was rare in limonoids and other natural products. Compound 1 showed nitric oxide (NO) inhibitory effect with an IC50 38.45 ± 0.41 µM in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages.