Two new triterpenoids from Nauclea officinalis

Two new triterpenoids and three 27-nor-triterpenoids were isolated from the stems (with bark) of Nauclea officinalis. Their structures were identified to be 2 beta,3 beta,19 alpha,23-tetrahydroxy-urs-12-en-28-oic acid (1), 2 beta,3 beta,19 alpha,23-tetrahydroxy-urs-12-en-28-O-[beta-d-glucopyranosyl (1-2)-beta-d-glucopyranosyl] ester (2), pyrocincholic acid 3 beta-O-alpha-l-rhamnopyranoside (3), pyrocincholic acid 3 beta-O-alpha-l-rhamnopyranosy1-28-O-beta-d-glucopyranosyl ester (4), pyrocincholic acid 3 beta-O-alpha-l-rhamnopyranosy1-28-O-beta-d-glucopyranosyl-(1-6)-beta-d-glucopyranosyl ester (5) by spectroscopic methods including 1D, 2D NMR and HR-MS analyses. The cytotoxic activity of 1-5 against lung cancer A-549 cells was also investigated.