BIOSYNTHESIS OF SECOIRIDOIDS IN FONTANESIA

Fontanesia fortunei was found to contain the new secoiridoid glucoside 7-E/Z-(p-coumaroyl)-5-hydroxysecologanol together with the known comp ounds secologanic acid, secologanol, secologanoside, fontanesioside, v erbascoside and chlorogenic acid. This secoiridoid profile is differen t from that found in other known genera of the Oleaceae, since no oleo side-derived compounds were present. Deuterium labelled deoxyloganic a cid, 7-epi-loganic acid and loganic acid were administered to F. fortu nei and F. phillyreoides and the incorporations into secologanic acid in both plants measured by H-2 NMR. Feeding experiments with specifica lly labelled compounds showed that the hydroxylation of deoxyloganic a cid to give loganic acid takes place with retention of the 7 alpha-hyd rogen and that the latter also is retained during the ring cleavage to secologanic acid.