Ursane- and oleanane-type triterpenes from Ternstroemia gymnanthera callus tissues.

An investigation on the constituents of the callus tissues of Ternstroemia gymnanthera has led to the isolation of five phytosterols, 15 known triterpenoids, and four new triterpenoids (1-4). The new compounds were characterized by spectroscopic study as 3-epi-corosolic acid lactone (2 alpha,3 alpha-dihydroxyurs-11-en-13 beta,28-olide) (1), 3-epi-ternstroemic acid (2 alpha,3 alpha-dihydroxyurs-12-en-11-on-28-oic acid) (2), ternstroemic acid (2 alpha,3 beta-dihydroxyurs-12-en-11-on-28-oic acid) (3), and gymnantheraic acid (2 alpha,3 alpha-dihydroxy-11 alpha-methoxyurs-12-en-28-oic acid) (4). The isolated triterpenes were compared with those from actinidiaceous plant callus tissues from a chemotaxonomic point of view.

Inhibition of DNA polymerases and DNA topoisomerase II by triterpenes produced by plant callus.

We found that some triterpene compounds could not only selectively inhibit the activities of mammalian DNA polymerase alpha (pol alpha) and beta (pol beta), but could also potently inhibit DNA topoisomerase II (topo II) [Biochem. J. 350 (2000) 757].