Regioisomeric structure determination of alpha- and gamma-linolenoyldilinoleoylglycerol in blackcurrant seed oil by silver ion high-performance liquid chromatography and mass spectrometry.
Gamma-linolenic acid (Gla) and oils containing Gla have evident positive effects on a variety of disorders, and therefore, the structure of triacylglycerols (TAGs) containing Gla is of special interest. The regioisomeric structures of TAGs 18:3(n-3)/18:2/18:2 (Ala/L/L) and 18:3(n-6)/18:2/18:2 (Gla/L/L) in blackcurrant seed oil were determined by Ag-HPLC/APCI-MS and Ag-HPLC/ESI-MS/MS techniques. In the latter, silver ion adducts were prepared by adding silver nitrate to the postcolumn flow. A new Ag-HPLC solvent system containing nonchlorinated solvents for the separation of Gla- and Ala-containing TAGs is introduced. Ag-HPLC separation of Ala/L/L and Gla/L/L was sufficient and regioisomers sn-LnLL + sn-LLLn and sn-LLnL (Ln, linolenic acid) could be differentiated well with the MS methods used. No discrimination was made between the sn-1 and sn-3 positions. The results show that the methods used are suitable to discriminate and determine the regioisomeric structure of TAGs. The regioisomeric structure of TAG with the fatty acid combination Gla/L/L in blackcurrant seed oil was considered to be practically random (32.7-37.8% of sn-LGlaL). In the fatty acid combination Ala/L/L, the regioisomeric structure is nonrandom (7.3-12.1% of sn-LAlaL) with Ala preferentially in a primary position. It can be concluded that the positional distribution of Ala and Gla is different in Ln/L/L TAGs of blackcurrant seed oil.
Leskinen
Heidi
H
Department of Biochemistry and Food Chemistry, University of Turku, Vatselankatu 2, 20014 Turku, Finland. hemahu@utu.fi
Suomela
Jukka-Pekka
JP
Pinta
Janne
J
Kallio
Heikki
H
D002851:Chromatography, High Pressure Liquid; D005990:Glycerol / Q000031:analogs & derivatives* / Q000032:analysis; D008042:Linolenic Acids / Q000032:analysis* / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure; D010938:Plant Oils / Q000737:chemistry*; D012834:Silver; D013237:Stereoisomerism; D014280:Triglycerides / Q000032:analysis*; D017965:gamma-Linolenic Acid / Q000032:analysis*
D008042:Linolenic Acids; D010938:Plant Oils; D014280:Triglycerides; C077230:blackcurrant seed oil; C531161:gamma-linolenoyldilinoleoylglycerol; D012834:Silver; D017965:gamma-Linolenic Acid; D005990:Glycerol