Five Novel Neuroprotective Triterpene Esters of Ulmus davidiana var. japonica

Investigation of the constituents of the stem and root barks of Ulmus davidiana var. japonica resulted in the isolation of five new triterpene esters named ulmicin A−E (1−5). Using several spectroscopic techniques, their structures were determined to be 3β,11α,15α-trihydroxylup-20(29)-ene-11-(3'-methoxy-4'-hydroxybenzoyl ester) (1), 3β,11α,15α-trihydroxylup-20(29)-ene-11-(4'-hydroxybenzoyl ester) (2), 3β,11α,15α-trihydroxylup-20(29)-ene-11-(3'-methoxy-4'-hydroxybenzoyl)-15-(4'-hydroxybenzoyl ester) (3), 3β,11α,15α-trihydroxylup-20(29)-ene-11,15-di(3'-methoxy-4'-hydroxybenzoyl ester) (4), and 3β,11α,15α-trihydroxylup-20(29)-ene-11-(3'-methoxy-4'-hydroxybenzoyl)-15-(benzoyl ester) (5). All five compounds showed significant neuroprotective activities against glutamate-induced neurotoxicity in primary cultures of rat cortical cells.