Three structurally related caffeic acid trimers, melitric acid A, methyl me
litrate A and the novel sagecoumarin, were isolated from sage and their che
mical structures elucidated by means of NMR spectroscopy and mass spectrosc
opy. The mechanism for their formation from salvianolic acid K was proposed
. (C) 1999 Elsevier Science Ltd. All rights reserved.