Isolation and Structure Determination of cis -OPDA-α-Monoglyceride from Arabidopsis thaliana .

cis -12-oxo-Phytodieneoic acid-α-monoglyceride ( 1 ) was isolated from Arabidopsis thaliana . The chemical structure of 1 was elucidated based on exhaustive 1D and 2D NMR spectroscopic measurements and supported by FDMS and HRFDMS data. The absolute configuration of the cis -OPDA moiety in 1 was determined by comparison of 1 H NMR spectra and ECD measurements. With respect to the absolute configuration of the β-position of the glycerol backbone, the 2:3 ratio of ( S ) to ( R ) was determined by making ester-bonded derivatives with ( R )-(+)-α-methoxy-α-trifluoromethylphenylacetyl chloride and comparing 1 H NMR spectra. Wounding stress did not increase endogenous levels of 1 , and it was revealed 1 had an inhibitory effect of A. thaliana post germination growth. Notably, the endogenous amount of 1 was higher than the amounts of (+)-7- iso -jasmonic acid and (+)- cis -OPDA in intact plants. 1 also showed antimicrobial activity against Gram-positive bacteria, but jasmonic acid did not. It was also found that α-linolenic acid-α-monoglyceride was converted into 1 in the A. thaliana plant, which implied α-linolenic acid-α-monoglyceride was a biosynthetic intermediate of 1 .