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

One new long-chain ester derivative of trans-ferulic acid and one natural tirucallane-type triterpenoid , together with forty known compounds (), were isolated from the barks of . Their structures were established on the basis of spectroscopic data interpretation. Compounds , , , , showed significant inhibitory activities against PTP1B with IC values of 13.