Isolation and structures of two divinyl ether fatty acids from Clematis vitalba.
[1-14C]Linolenic acid was incubated with a homogenate of leaves of Clematis vitalba, a plant belonging to the Ranunculaceae family. Analysis of the reaction product by reversed-phase high-performance liquid radiochromatography demonstrated the presence of the following labeled oxylipins: 12-oxo-10, 15(Z)-phytodienoic acid, 9(S)-hydroxy-10(E), 12(Z), 15(Z)-octadecatrienoic acid, omega5(Z)-etherolenic acid, and 9-[1'(E), 3'(Z),6'(Z)-nonatrienyloxy]-8(Z)-nonenoic acid [8(Z)-colnelenic acid]. The last compound was a new divinyl ether FA, and an analogous compound, i.e., 9-[1'(E),3'(Z)-nonadienyloxy]-8(Z)-nonenoic acid [8(Z)-colneleic acid], was obtained following incubation of linoleic acid with the Clematis homogenate. Structures of the two divinyl ethers were assigned by spectral and chromatographic comparison with authentic compounds prepared synthetically using previously described methodology. Separate incubation of the 9- and 13-hydroperoxides of linolenic acid demonstrated that the first hydroperoxide served as the precursor of 8(Z)-colnelenic acid and indicated the presence in C. vitalba of a new divinyl ether synthase acting on 9-lipoxygenase-generated hydroperoxides. A close structural relationship between this enzyme and the well-studied divinyl ether synthase in the potato and tomato seems likely.
Hamberg
Mats
M
Department of Medical Biochemistry and Biophysics, Karolinska Institutet, S-171 77 Stockholm, Sweden. Mats.Hamberg@mbb.ki.se
D002851:Chromatography, High Pressure Liquid; D039324:Clematis / Q000737:chemistry*; D003577:Cytochrome P-450 Enzyme System; D005227:Fatty Acids / Q000302:isolation & purification*; D006861:Hydrogen Peroxide / Q000378:metabolism; D008084:Lipoxygenase / Q000378:metabolism; D010088:Oxidoreductases; D018515:Plant Leaves / Q000737:chemistry; D010940:Plant Proteins; D014753:Vinyl Compounds / Q000302:isolation & purification*
D005227:Fatty Acids; D010940:Plant Proteins; D014753:Vinyl Compounds; C100195:vinyl ether; D003577:Cytochrome P-450 Enzyme System; D006861:Hydrogen Peroxide; D010088:Oxidoreductases; C100485:divinyl ether synthase; D008084:Lipoxygenase