Stilbenes and Related Compounds
extend chain of p-coumaric acid by adding malonyl-CoA units
add one and cyclize ----> dihydropyrones
add two and cyclize ----> styryl pyrones
add three and cyclize by aldol condensation ----> stilbenes (e.g., pinosylvin)
add three and cyclize by Claisen condensation----> flavonoids
C6-C1 ----> add three ----> xanthones
e.g., maclurin and mangiferin
Dihydropyrones
paracotin, kawain, etc. from kava kava and coto bark
diuretic, soporific, anticonvulsant, spasmolytic
skeletal muscle relaxant
Stilbenes
about 200 stilbenes are known
often in the heartwood of trees, especially in Pinus, Eucalyptus, Maclura
smaller amount of stilbene glycosides in the vegetative parts
resveratrol
"resveratrol synthase" has been isolated and studied from grape leaves. This is probably the most common of these compounds.
lunularic acid in byrophytes
seems to "replace" ABA, but not active in higher plants
many of these compounds cause problems in paper manufacture
most active is piceatannol "cytotoxic"
many are antifungal
several are phytoalexins
several are phytoalexins in one tissue, but are constitutive defenses in other tissues
α- and ε-viniferin also are phytoalexins in grapes
Phenanthrenes
stilbenes ----> phenanthrenes
radical coupling, ortho or para (in this case ortho), e.g., in Orchis militaris to produce orcinol
batatasins are dormancy factors in Dioscorea species
Xanthones
about 150 known, both polyketide and skikimic acid derived
C6-C1 ----> add three malonates ----> Claisen condensation ----> benzophenones ----> xanthones
Related Images
extension of p-hydroxycinnamoyl-CoA by malonyl-CoA
Plants with Stilbenes and
Related Compounds
© David S. Seigler, Integrative Biology 425, Plant Secondary Metabolism, Department of Plant
Biology, 265 Morrill Hall, 505 S. Goodwin Ave., University of Illinois, Urbana, Illinois 61801, USA.
217-333-7577. seigler@life.uiuc.edu.
