Oleoyl-lysophosphatidic acid

This structure was confirmed as follows. Commercially available 1-oleoyl-2-lysophosphatidic acid (21) was methylated with diazomethane in ether to yield the monomethyl and dimethyl esters, which were respectively positive and negative in the Dittmer test. Chromatographic and spectroscopic properties of synthesized monomethyl ester (22) were in good agreement with those of the natural repellent except for minor features reflecting differences in the fatty acid part of each molecule. 

Compounds 19 and 20 along with some acylated phosphatidic derivatives in addition to 1,2-dioleoylphosphatidic acid, were tested using the particle bioassay [83]. Commercially available l-oleoyl-2-lysophosphatidic acid (21) possessed repellent activity which was enhanced by monomethylation. When A. cochlioides zoospores were pre-treated with an excess of the natural stimulant N-frans-feruloyltyramine (19), and then exposed to Chromosorb W AW particles coated with various test compounds, it was found that 1 -oleoyl-2-lysophosphatidic (21, 100 ppm) and its monomethyl ester (22) (10 ppm), as well as the natural repellent 1-linoleoyl-2-lysophosphatidic acid monomethyl ester (20, 30 ppm), effectively inhibited zoospore motility [83], However, l-oleoyl-2-lysophosphatidic acid dimethyl ester (23) and 1,2-dioleoylphosphatidic acid tested with and without the stimulant (19) showed neither repellent nor motility inhibitory activity. The bioassay revealed that compounds possessing repellent activity are monoacylated phosphatidic acid derivatives containing at least one hydroxy group on the phosphoryl unit [83]. 

DAG, diacylglycerols FFA, fiee fatty acids LPA/PA, lysophosphatidic acids/phosphatidic acids PC, phosphatidylcholines TAG, triacylgjycerols.In the absence of malonyl-CoA and/or reducing equivalents no elongation of C-oleoyl was observed. 2-Bromo-octanoate (2-BrOA) supplied at a final concentration of 1.5 mM. No other C-acyl moieties were detected... 

---