Submitted to: Journal of the American Oil Chemists' Society
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/21/2013
Publication Date: 12/1/2013
Publication URL: http://dx.doi.org/10.1007/s11746-013-2313-1
Citation: Lin, J.T., Chen, G.Q. 2013. Identification of TAG and DAG and their FA constituents in Lesquerella (Physaria fendleri) oil by HPLC and MS. Journal of the American Oil Chemists' Society. 90:1819-1829.
Interpretive Summary: Ricinoleate, a hydroxy fatty acid, in castor oil has many industrial uses such as the manufacture of biodegradable plastics, plasticizers, lubricants, cosmetics, paints and surfactants. Castor is the only commercial source of ricinoleate. However castor bean contains toxin, ricin, as well as potent allergens, it is hazardous to grow, harvest and process castor. It is desirable to produce ricinoleate in an oilseed of a transgenic plant lacking these toxic components. Lesquerella fendleri contains no such toxic components. Its oil contains ricinoleate and thus the plant can be developed to produce high level of ricinoleate for industrial uses. Lesquerolate, a C20 homolog of ricinoleate, is the major fatty acid in lesquerella oil. Lesquerolate can also be used for industry similar to those of ricinoleate. Many acylglycerols in lesquerella oil were identified and quantified for the development of Lesquerella fendleri to produce high level of ricinoleate and for the industrial uses of hydroxy fatty acids in lesquerella oil.
Technical Abstract: Castor oil has many industrial uses because of its high content (90 %) of the hydroxy fatty acid, ricinoleic acid (OH1218:19). Lesquerella oil containing lesquerolic acid (Ls, OH1420:111) is potentially useful in industry. Ten molecular species of diacylglycerols and 74 molecular species of triacylglycerols in lesquerella (Physaria fendleri) oil were identified by electrospray ionization mass spectrometry as lithium adducts of acylglycerols in the HPLC fractions of lesquerella oil. Among them were: LsLsO, LsLsLn, LsLsL, LsLn–OH20:2, LsO–OH20:2 and LsL–OH20:2. The structures of the four new hydroxy fatty acid constituents of acylglycerols were proposed by the MS of the lithium adducts of fatty acids as (comparing to those in castor oil): OH1218:29,14 (OH1218:29,13 in castor oil), OH1218:39,14,16 (OH18:3 not detected in castor oil), diOH12,1318:29,14 (diOH11,1218:29,13 in castor oil) and diOH13,1420:111 (diOH20:1 not detected in castor oil, diOH11,1218:19 in castor oil). Trihydroxy fatty acids were not detected in lesquerella oil. The differences in the structures of these C18 hydroxy fatty acids between lesquerella and castor oils indicated that the polyhydroxy fatty acids were biosynthesized and were not the result of autoxidation products.