Positional‐Species Composition of Diacylglycerol Acetates from Mature Euonymus Seeds

Abstract

The positional-species composition (PSC) of 3-acetyl-1,2-diacyl-sn-glycerols (AcDAGs) from the seeds of mature fruits of 14 species of the genus Euonymus L. was established. The residues of six major fatty acids (FAs), palmitic (P), stearic (St), hexadecenoic (H), octadecenoic (O), linoleic (L), and linolenic (Ln), were present in the AcDAGs. Here, we demonstrated that the profile of PSC of AcDAGs could serve as chemotaxonomic factor to divide euonymus species studied here into groups which completely correlate with the present day systematic of the genus. In particular, the Euonymus section greatly exceeded other sections of the Euonymus subgenus as well as the Kalonymus one in the total levels of AcDAGs positional species having one and two O residues and was characterized by significantly lesser concentrations of species with one and two L residues. Moreover, in seed, AcDAGs of almost all Euonymus species EFL values were slightly higher than EFO ones, but all EFL and EFO values were higher than 1.0, and therefore, it can be concluded that both FAs mainly esterified sn-2-position of the glycerol moiety and saturated FAs residues were always virtually absent in the sn-2 position of Euonymus seed AcDAGs, as it is also the case in nearly all TAGs molecules of plant origin.

Defining the extreme substrate specificity of Euonymus alatus diacylglycerol acetyltransferase, an unusual membrane-bound O-acyltransferase

“…This might be due to their very low abundances in microsomes (Figure 2A), the low preference of Ea DAcT for these DAG, or a combination of both effects. These results suggesting that Ea DAcT preferentially acetylates DAG species with higher unsaturation levels than those with lower saturation levels are consistent with the high incorporation of polyunsaturated fatty acids in the acetyl-TAGs naturally found in the endosperm of E. alatus [20] and transgenically produced in Camelina seeds expressing Ea DAcT [10]. …”

Evidence of Strict Stereospecificity in the Structure of sn‐1,2‐Diacyl‐3‐Acetyl‐Glycerols from Euonymus maximowiczianus Seeds Using Nuclear Magnetic Resonance Spectroscopy

“…Previously, we had described both the FA contents of Ac DAG accumulated in the seeds of 14 species of the Euonymus genus, the features of FA acyl distribution between the sn ‐1 and sn ‐2 positions in the glycerol residue of Ac DAG, and their position‐type and position‐special contents in detail (Sidorov et al, , ). For this study, we chose Ac DAG isolated from the mature seeds of E. maximowiczianus because the contents of FA acylating the sn ‐1 and sn ‐2 positions of Ac DAG were very simple: 17.5% palmitic, 4.4% stearic, 37.0% oleic, 33.0% linoleic, 7.8% α‐linolenic, and 0.3% minor FA (Sidorov et al, ).…”

“…Ac DAG containing usual FA residues at the sn ‐1,2 positions were described by Kleiman, Miller, Earle, and Wolff () in oils from 13 plant species belonging to nonclosely related families, namely Celastraceae, Lardizabalaceae, Ranunculaceae, and Rosaceae. Apart from the aforesaid plants, nowadays Ac DAG are found in lipocytes of cow udders, in milk butter, in fat depots of Eurosta solidaginis fly larvae, and in other organisms (Sidorov, Pchelkin, Zhukov, & Tsydendambaev, ).…”

Polyunsaturated and Very‐Long‐Chain Fatty Acids Are Involved in the Adaptation of Maloideae (Rosaceae) to Combined Stress in the Mountains

“…To extract lipids, isopropanol was separated through a Schott glass filter into a 250 ml volumetric flask and plant material was homogenized in a porcelain mortar and extracted as previously described with slight modifications . Lipids were extracted three times sequentially in chloroform/methanol/H 2 O (30:20:1.7, by vol.)…”