THE STRUCTURE OF THE TRIACYLGLYCEROLS, CONTAINING PUNICIC ACID, IN THE SEED OIL OF TRICHOSANTHES KIRILOWII

Triacylglycerols of the seed oil of Trichosanthes kirilowii have been resolved by high-performance liquid chromatography (HPLC) in the silve r-ion and reverse-phase modes. The fatty acids were identified by gas chromatography/mass spectrometry as the picolinyl esters. The main com ponents are cis,cis-C18:2n-6 (38.2 mole%), C18:3(9c,11t,13c) (punicic acid, 38.0 mole%), and cis-C18:1n-9 (11.8 mole%). Small amounts of C18 :3(9c,11t,13c) (alpha-eleostearic acid) and C18:3(9t,11t,13c)(catalpic acid) were detected. Silver-ion HPLC exhibited excellent resolution i n which fractions were resolved on the basis of the number and configu ration of double-bonds. In this instance, the strength of interaction of a conjugated trienoic double-bond system with silver ions seemed to be between that of dienoic and monoenoic double bond systems. The tri acylglycerols were also separated into 20 fractions by reverse-phase H PLC, and the iractionation was achieved according to the partition num ber in which a conjugated trienoic double bond was not equivalent to t hree monoenoic double bonds in a molecule with a given chainlength. Th e principal triacylglycerol species are (C18:2n-6) (C18:3(9c,11t,13c)) (2) (28.3 mol% of total), (C18:1n-9)(C18:2n-6) (C18:3(9c,11t,13c)) (19 .0 mol%), and (C18:2n-6)(2)(C18:3(9c,11t,13c)) (16.2 mol%), while simp le triacylglycerols such as (C18:3(9c,11t,13c))(3) and (C18:2n-6)(3) w ere present as minor components only (<1.0 mol%). Species esterified w ith conjugated trienoic acids comprise more than 96% of the total. Ste reospecific analysis gave rise to insurmountable difficulties, but it is evident that there is some asymmetry in the distribution of fatty a cids in the molecules.