Identification of (12-ricinoleoylricinoleoyl)diricinoleoylglycerol, an acylglycerol containing four acyl chains, in castor (Ricinus communis L.) oil by LC-ESI-MS.
An acylglycerol (AG) containing four acyl chains, (12-ricinoleoylricinoleoyl)diricinoleoylglycerol (RRRR), was positively identified for the first time in a natural source in castor oil using electrospray ionization tandem mass spectrometry (ESI-MS/MS). HPLC-purified RRRR from castor oil was subjected to ion trap and high-resolution ESI-MS/MS. The precursor and fragment ions of [RRRR + Na]+ showed the expected masses, and the sodiated fragment ions of both diacylglycerols and fatty acids were detected. Because fragment ions of fatty acids from [AG + NH4]+ adducts cannot be detected by ESI-MS/MS, [AG + Na]+ adducts are more informative. Radiolabeled triricinolein (RRR) was incorporated into RRRR in castor microsomes, indicating that RRRR is biosynthesized in castor bean. This newly identified and biosynthesized RRRR represents a new AG subclass of tetra-acylglycerols (or acylacyldiacylglycerol).
Lin
Jiann-Tsyh
JT
Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, 800 Buchanan Street, Albany, California 94710, USA. jtlin@pw.usda.gov
Arcinas
Arthur
A
Harden
Leslie R
LR
Fagerquist
Clifton K
CK
D000215:Acylation; D002367:Ricinus communis / Q000737:chemistry; D002368:Castor Oil / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods; D005989:Glycerides / Q000302:isolation & purification*; D015394:Molecular Structure; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D014280:Triglycerides / Q000096:biosynthesis / Q000737:chemistry / Q000302:isolation & purification*
C530288:2-(12-ricinoleoylricinoleoyl)-1,3-diricinoleoylglycerol; D005989:Glycerides; D014280:Triglycerides; D002368:Castor Oil