R. Imbusch et Mj. Mueller, Formation of isoprostane F-2-like compounds (phytoprostanes F-1) from alpha-linolenic acid in plants, FREE RAD B, 28(5), 2000, pp. 720-726
Isoprostanes F-2 are biologically active prostaglandin F-2-like compounds f
ormed by free radical-catalyzed oxidation of arachidonic acid (C20:4). Here
. we show that a series of diner isoprostanes F-1, which we term phytoprost
anes F-1 (PPF(1)s), are formed by nonenzymatic oxidation of linolenate (C18
:3) in plants. Identification and quantification of PPF(1)s were achieved b
y a negative ion chemical ionization gas chromotography-mass spectrometry m
ethod using oxygen 18-labeled PPF(1)s as internal standards. PPF(1)s were f
ound in leaves, flowers, and roots of taxonomically distinct plant species
at concentrations ranging from 43 to 1380 ng/g of dry weight. In addition,
esterified PPF(1)s were found at 10- to 150-fold higher concentrations. Dur
ing the drying and storage of various plant organs, endogenous PPF1 levels
increased dramatically by 15- to 263-fold. Because the structurally related
prostaglandin F-2 alpha and isoprostanes F-2 exert potent biological activ
ities (i.e., broncho- and vasoconstriction) in the: nanomolar range, PPF(1)
s could potentially exert similar biological activities. Notably, fresh bir
ch pollen, which ran easily be inhaled, contains exceedingly high concentra
tions (32,440 ng/g) of free PPF(1)s. (C) 2000 Elsevier Science Inc.