Chemical constituents from the leaves of Clausena lansium and their anti-inflammatory activity

Five new acyclic amides clausenalansamides C-G (1-5) together with 39 known compounds were characterized from the leaves of Clausena lansium (Lour.) Skeels (Rutaceae). Their structures were established by spectroscopic methods, and the absolute configurations were determined by electronic circular dichroism and single-crystal X-ray diffraction analyses with Cu Kα radiation. Most of the isolated compounds were evaluated for their potential anti-inflammatory activity. Among the test compounds, imperatorin (11) and wampetin (12) displayed the most significant inhibition of fMLP/CB induced superoxide anion generation with IC₅₀ values of 1.7 ± 0.3 and 6.8 ± 1.1 µM, respectively. Moreover, the neuroprotective effect of the isolated compounds on Aβ25 – 35 neurotoxicity in vitro was also investigated. Among all the compounds, 6-O-methyl-epi-neoclausenamide showed protective activity of Aβ 25 – 35 cortical neuron cells death with 22.4% at 50 µM.