B-seco limonoids from the bark of Toona ciliata

Toonayunnanaes A-E (1-5), five B-seco limonoids, along with five known compounds (6-10) were isolated from the bark of Toona ciliata. Compound 1 is a limonoid with a epsilon-7(8)-lactone in the B ring, and compound 2 possesses a 1,14-oxygen bridge and a 15-OH. Their structures were elucidated by extensive spectroscopic analysis including 1D and 2D NMR, and HRESIMS. Compound 1 exhibited significant inhibition effect of NO production in LPS-stimulated RAW264.7 macrophages with an IC50 value of 10.94 +/- 0.08 mu M.