Chemical constituents from the barks of Melia azedarach and their PTP1B inhibitory activity.

One new long-chain ester derivative of trans-ferulic acid 1 and one natural tirucallane-type triterpenoid 2, together with forty known compounds (3-42), were isolated from the barks of Melia azedarach. Their structures were established on the basis of spectroscopic data interpretation. Compounds 7, 9, 10, 12, 13 showed significant inhibitory activities against PTP1B with IC50 values of 13.82 ± 1.29 µM, 13.29 ± 2.26 µM, 20.27 ± 0.52 µM, 24.36 ± 1.25 µM, 15.23 ± 0.6 µM, respectively.