Antifungal 3-butylisocoumarins from Asteraceae-Anthemideae.
Seven new naturally occurring 3-butylisocoumarins were isolated and identified from lipophilic extracts of aerial as well as underground organs: corfin (17) and 3'-hydroxycorfin (18) from the roots of Chamaemelum mixtum and (-)-(R)-2'-methoxydihydroartemidin (5), (+)-(S,R)-epoxyartemidin (6a), dracumerin (12), (+)-(R)-(E)-3'-hydroxyartemidin (13), and capillarin isovalerate (20) from various organs of Artemisia dracunculus (tarragon). Furthermore, six known derivatives, artemidiol (7), (E/Z)-artemidin (11), capillarin (19), artemidinol (21), 8-hydroxyartemidin (22), and 8-hydroxycapillarin (23), were obtained. The antifungal activities of all naturally occurring derivatives were determined in a germ-tube inhibition test against a susceptible strain of rice blast fungus Pyricularia grisea. The 3-butyl side-chain is a prerequisite for high activity. Eleven structurally related synthetic derivatives were additionally tested to explore the influence of structural characteristics on activity. Benlate, blasticidin S, kresoxim-methyl, griseofulvin, and the carrot phytoalexin 6-methoxymellein all served as positive controls.
Engelmeier
D
D
Comparative and Ecological Phytochemistry Department, Institute of Botany, Rennweg 14, A-1030 Vienna, Austria.
Hadacek
F
F
Hofer
O
O
Lutz-Kutschera
G
G
Nagl
M
M
Wurz
G
G
Greger
H
H
D000935:Antifungal Agents / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D001203:Ascomycota / Q000187:drug effects* / Q000472:pathogenicity; D019659:Asteraceae / Q000737:chemistry*; D001317:Austria; D003374:Coumarins / Q000737:chemistry / Q000302:isolation & purification* / Q000494:pharmacology; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D018515:Plant Leaves / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship
D000935:Antifungal Agents; D003374:Coumarins