A novel alkaloid, aristopyridinone A and anti-inflammatory phenanthrenes isolated from Aristolochia manshuriensis.

A novel alkaloid, aristopyridinone A (1) and a new phenanthrene, aristolamide II (2), were isolated from Aristolochia manshuriensis (Guanmutong) together with eight known phenanthrenes (3-10). All structures were elucidated by spectroscopic methods. Compound 2 showed a selective inhibitory effect on elastase release by human neutrophils in response to fMLP with an IC(50) value of 4.11 μg/mL. Compound 7 exhibited significant inhibitory effects on superoxide anion generation and elastase release with IC(50) values of 0.12 and 0.20 μg/mL, respectively.