Effect of Docosahexaenoic Acid Encapsulation with Whey Proteins on Rat Growth and Tissue Endocannabinoid Profile.

Modifying the food structure allows a nutrient to be delivered differently, which can modify not only its digestion process but also its subsequent metabolism. In this study, rats received 3 g of omelette daily containing docosahexaenoic acid (DHA) as crude oil or previously encapsulated with whey proteins, whereas a control group received a DHA-free omelette. The results showed that DHA encapsulation markedly induced a different feeding behaviour so animals ate more and grew faster. Then, after four weeks, endocannabinoids and other N-acyl ethanolamides were quantified in plasma, brain, and heart. DHA supplementation strongly reduced endocannabinoid derivatives from omega-6 fatty acids. However, DHA encapsulation had no particular effect, other than a great increase in the content of DHA-derived docosahexaenoyl ethanolamide in the heart. While DHA supplementation has indeed shown an effect on cannabinoid profiles, its physiological effect appears to be mediated more through more efficient digestion of DHA oil droplets in the case of DHA encapsulation. Thus, the greater release of DHA and other dietary cannabinoids present may have activated the cannabinoid system differently, possibly more locally along the gastrointestinal tract. However, further studies are needed to evaluate the synergy between DHA encapsulation, fasting, hormones regulating food intake, and animal growth.

Encapsulation of DHA oil with heat-denatured whey protein in Pickering emulsion improves its bioaccessibility.

This study compared the bioaccessibility of docosahexaenoic acid (DHA) provided encapsulated or unencapsulated within a food matrix. DHA oil was composed of DHA-enriched triacylglycerols prepared as Pickering emulsion by encapsulation with heat-denatured whey protein isolate particles and then incorporated into homogenized liquid egg to get omelets. The effect of encapsulation was analyzed by using a static in vitro digestion model of the adult, which digestive fluid enzymes have also been characterized by proteomics. First, the size of lipid droplets was shown to be smaller and uniformly dispersed in omelets with encapsulated-DHA oil compared to non-encapsulated-DHA oil. Distribution of droplets was more regular with encapsulated-DHA oil as well. As a consequence, we showed that encapsulating DHA oil promoted the hydrolysis by pancreatic lipase during the intestinal phase. A larger proportion of DHA enriched-triacylglycerols was hydrolyzed after two hours of digestion, leading to a greater release in free DHA. Thus, only 32% of DHA remained esterified in the triacylglycerols with encapsulated-DHA oil, compared to 43% with non-encapsulated-DHA oil. The DHA in free form ultimately represented 52% of the total DHA with encapsulated-DHA oil, compared to 40% with non-encapsulated-DHA oil. Finally, our results showed that as much DHA was released after one hour of intestinal digestion when the DHA oil was encapsulated as after two hours when the DHA oil was not encapsulated. Therefore, DHA bioaccessibility was significantly improved by encapsulation of DHA oil in omelets.

Encapsulation of Docosahexaenoic Acid Oil Substantially Improves the Oxylipin Profile of Rat Tissues.

Docosahexaenoic acid (DHA) is a major n-3 polyunsaturated fatty acid (PUFA) particularly involved in cognitive and cardiovascular functions. Due to the high unsaturation index, its dietary intake form has been considered to improve oxidation status and to favor bioaccessibility and bioavailability as well. This study aimed at investigating the effect of DHA encapsulated with natural whey protein. DHA was dietary provided as triacylglycerols to achieve 2.3% over total fatty acids. It was daily supplied to weanling rats for four weeks in omelet as food matrix, consecutively to a 6-hour fasting. First, when DHA oil was encapsulated, consumption of chow diet was enhanced leading to promote animal growth. Second, the brain exhibited a high accretion of 22.8% DHA, which was not improved by dietary supplementation of DHA. Encapsulation of DHA oil did not greatly affect the fatty acid proportions in tissues, but remarkably modified the profile of oxidized metabolites of fatty acids in plasma, heart, and even brain. Specific oxylipins derived from DHA were upgraded, such as Protectin Dx in heart and 14-HDoHE in brain, whereas those generated from n-6 PUFAs were mainly mitigated. This effect did not result from oxylipins measured in DHA oil since DHA and EPA derivatives were undetected after food processing. Collectively, these data suggested that dietary encapsulation of DHA oil triggered a more efficient absorption of DHA, the metabolism of which was enhanced more than its own accretion in our experimental conditions. Incorporating DHA oil in functional food may finally improve the global health status by generating precursors of protectins and maresins.

Sciadonic acid derived from pine nuts as a food component to reduce plasma triglycerides by inhibiting the rat hepatic Δ9-desaturase.

Sciadonic acid (Scia) is a Δ5-olefinic fatty acid that is particularly abundant in edible pine seeds and that exhibits an unusual polymethylene-interrupted structure. Earlier studies suggested that Scia inhibited the in vitro expression and activity of the Stearoyl-CoA Desaturase 1 (SCD1), the hepatic Δ9-desaturase involved in the formation of mono-unsaturated fatty acids. To confirm this hypothesis, rats were given 10% Scia in diets balanced out with n-6 and n-3 fatty acids. In those animals receiving the Scia supplement, monoene synthesis in the liver was reduced, which was partly attributed to the inhibition of SCD1 expression. As a consequence, the presence of Scia induced a 50% decrease in triglycerides in blood plasma due to a reduced level of VLDL-secreted triglycerides from the liver. In non-fasting conditions, results showed that Scia-induced inhibition of SCD1 led to a decrease in the proportions of 16:1n-7 and 18:1n-7 in the liver without impacting on the level of 18:1n-9, suggesting that only triglycerides with neosynthesized monoenes are marked out for release. In conclusion, this in vivo study confirms that Scia highly inhibits SCD1 expression and activity. The work was performed on normo-triglyceride rats over six weeks, suggesting promising effects on hyper-triglyceridemic models.

Interactive effects of maternal and weaning high linoleic acid intake on hepatic lipid metabolism, oxylipins profile and hepatic steatosis in offspring.

Non-alcoholic fatty liver disease (NAFLD) has been described as a hepatic manifestation of the metabolic syndrome. When several studies correlated maternal linoleic acid (LA) intake with the development of obesity, only few links have been made between n-6 fatty acid (FA) and NAFLD. Herein, we investigated the influence of both maternal and weaning high LA intake on lipid metabolism and susceptibility to develop later metabolic diseases in offspring. Pregnant rats were fed a control-diet (2% LA) or a LA-rich diet (12% LA) during gestation and lactation. At weaning, offspring was assigned to one of the two diets, i.e., either maintained on the same maternal diet or fed the other diet for 6 months. Physiological, biochemical parameters and hepatic FA metabolism were analyzed. We demonstrated that the interaction between the maternal and weaning LA intake altered metabolism in offspring and could lead to hepatic steatosis. This phenotype was associated with altered hepatic FA content and lipid metabolism. Interaction between maternal and weaning LA intake led to a specific pattern of n-6 and n-3 oxylipins that could participate to the development of hepatic steatosis in offspring. Our findings highlight the significant interaction between maternal and weaning high LA intake to predispose offspring to later metabolic disease and support the predictive adaptive response hypothesis.

The Hypotriglyceridemic Effect of Sciadonic Acid is Mediated by the Inhibition of Δ9-Desaturase Expression and Activity.

SCOPE: Sciadonic acid (Scia; 20:3Δ5,11,14) is a distinctive fatty acid (FA) with a polymethylene-interrupted double bond at C5. It is specifically found in seeds from gymnosperms such as pine nuts. Published papers describe a decrease in liver and plasma triacylglycerols in rats fed with this nutriment. The present study seeks to identify the action mechanism of Scia on triacylglycerol synthesis. In this way, its nutritional effect on FA metabolism involving the Stearoyl-CoA Desaturase 1 (SCD1) is investigated. METHODS AND RESULTS: Scia is discerned in trace amount in various tissues of rats and in human serum. It is produced by Δ5-desaturation of 20:2n-6 in human transfected SH-SY5Y cell lines and also in rat hepatocytes. When Scia is incubated with cultured hepatocytes as a nutrient, the cellular FA profile is modified. In particular, the proportion of the monoenes (18:1n-9, 18:1n-7, 16:1n-7) are all decreased, correlating to the reduction of triacylglycerol amounts. This effect is mediated by the inhibition of SCD1 expression. Furthermore, Scia, as well as 20:3n-6 and 20:3n-9 but not 20:3n-3, strongly inhibit the SCD1 activity measured on liver microsomes. CONCLUSION: Overall, this study shows that Scia, despite its unusual structure, contributes to the FA metabolism and reduced triacylglycerol release by inhibiting SCD1 activity.

The 51 kDa FADS3 is secreted in the ECM of hepatocytes and blood in rat.

The fatty acid desaturase (Fads) cluster is composed of three genes encoding for the Δ5- and Δ6-desaturases and FADS3. The two former proteins are involved in the fatty acid biosynthesis; the latter one shares a high sequence identity but has still no attributed function. In a previous work performed in rat, we described three isoforms of FADS3 expressed in a tissue-dependent manner. In the present study, we demonstrated a specific subcellular targeting depending on the isoform. In cultured hepatocytes, which mainly expressed the 51 kDa protein, FADS3 was unexpectedly present in the cytosolic fraction, but was also secreted in the extracellular matrix on fibronectin-containing fibers. The secretion pathway was investigated and we determined the presence of exosome-like vesicles on the FADS3-stained fibers. In parallel, FADS3 was detected in blood of hepatic vessel, and particularly in serum. In conclusion, this study demonstrated a very specific intra- and extracellular location of FADS3 in comparison with the Δ5- and Δ6-desaturases, suggesting a unique function for this putative desaturase, even if no activity has been yet identified neither in the extracellular matrix of hepatocytes nor in serum.

Trans-vaccenate is Δ13-desaturated by FADS3 in rodents.

Fatty acid desaturases play critical roles in regulating the biosynthesis of unsaturated fatty acids in all biological kingdoms. As opposed to plants, mammals are so far characterized by the absence of desaturases introducing additional double bonds at the methyl-end site of fatty acids. However, the function of the mammalian fatty acid desaturase 3 (FADS3) gene remains unknown. This gene is located within the FADS cluster and presents a high nucleotide sequence homology with FADS1 (Δ5-desaturase) and FADS2 (Δ6-desaturase). Here, we show that rat FADS3 displays no common Δ5-, Δ6- or Δ9-desaturase activity but is able to catalyze the unexpected Δ13-desaturation of trans-vaccenate. Although there is no standard for complete conclusive identification, structural characterization strongly suggests that the Δ11,13-conjugated linoleic acid (CLA) produced by FADS3 from trans-vaccenate is the trans11,cis13-CLA isomer. In rat hepatocytes, knockdown of FADS3 expression specifically reduces trans-vaccenate Δ13-desaturation. Evidence is presented that FADS3 is the first "methyl-end" fatty acid desaturase functionally characterized in mammals.

Regulation of mammalian desaturases by myristic acid: N-terminal myristoylation and other modulations.

Myristic acid, the 14-carbon saturated fatty acid (C14:0), usually accounts for small amounts (0.5%-1% weight of total fatty acids) in animal tissues. Since it is a relatively rare molecule in the cells, the specific properties and functional roles of myristic acid have not been fully studied and described. Like other dietary saturated fatty acids (palmitic acid, lauric acid), this fatty acid is usually associated with negative consequences for human health. Indeed, in industrialized countries, its excessive consumption correlates with an increase in plasma cholesterol and mortality due to cardiovascular diseases. Nevertheless, one feature of myristoyl-CoA is its ability to be covalently linked to the N-terminal glycine residue of eukaryotic and viral proteins. This reaction is called N-terminal myristoylation. Through the myristoylation of hundreds of substrate proteins, myristic acid can activate many physiological pathways. This review deals with these potentially activated pathways. It focuses on the following emerging findings on the biological ability of myristic acid to regulate the activity of mammalian desaturases: (i) recent findings have described it as a regulator of the Δ4-desaturation of dihydroceramide to ceramide; (ii) studies have demonstrated that it is an activator of the Δ6-desaturation of polyunsaturated fatty acids; and (iii) myristic acid itself is a substrate of some fatty acid desaturases. This article discusses several topics, such as the myristoylation of the dihydroceramide Δ4-desaturase, the myristoylation of the NADH-cytochrome b5 reductase which is part of the whole desaturase complex, and other putative mechanisms.

Short chain saturated fatty acids decrease circulating cholesterol and increase tissue PUFA content in the rat.

This study investigates the effect of various dietary saturated fatty acid (SFA) profiles on plasma lipid parameters and tissue fatty acid composition in rats. The experiment was designed to monitor polyunsaturated fatty acids (PUFA) levels, while examining different amounts and types of SFA. Four isocaloric diets were prepared, containing 10-11 mol% of fatty acids (FA) as linoleic acid (LNA) and 2.5 mol% as α-linolenic acid (ALA), leading to an identical and well-balanced LNA/ALA ratio. The initial rapeseed oil/corn oil mixture providing ALA and LNA was enriched with olive oil to prepare the olive oil diet. The butterfat diet was supplemented with butterfat, containing short-chain SFA (C4:0-C10:0, 17 mol% of FA), lauric acid (C12:0, 3.2 mol%), myristic acid (C14:0, 10.5 mol%) and palmitic acid (C16:0, 14.5 mol%). The saturates diet was supplemented with trilaurin, trimyristin and tripalmitin to obtain the same level of lauric, myristic and palmitic acids as the butterfat diet, without the short-chain SFA. The trimyristin diet was enriched with trimyristin only. The results showed that the butterfat diet contributed to specific effects, compared to the olive oil diet and the saturates and trimyristin diets: a decrease in plasma total, LDL- and HDL-cholesterol, higher tissue storage of ALA and LNA, and a higher level of (n-3) highly unsaturated fatty acids in some tissues. This study supports the hypothesis that in diets with identical well-balanced LNA/ALA ratios, short chain SFA may decrease circulating cholesterol and increase tissue polyunsaturated fatty acid content in the rat.

Multiple beneficial health effects of natural alkylglycerols from shark liver oil.

Alkylglycerols (alkyl-Gro) are ether lipids abundant in the liver of some elasmobranch fish species such as ratfishes and some sharks. Shark liver oil from Centrophorus squamosus (SLO), or alkyl-Gro mix from this source, have several in vivo biological activities including stimulation of hematopoiesis and immunological defences, sperm quality improvement, or anti-tumor and anti-metastasis activities. Several mechanisms are suggested for these multiple activities, resulting from incorporation of alkyl-Gro into membrane phospholipids, and lipid signaling interactions. Natural alkyl-Gro mix from SLO contains several alkyl-Gro, varying by chain length and unsaturation. Six prominent constituents of natural alkyl-Gro mix, namely 12:0, 14:0, 16:0, 18:0, 16:1 n-7, and 18:1 n-9 alkyl-Gro, were synthesized and tested for anti-tumor and anti-metastatic activities on a model of grafted tumor in mice (3LL cells). 16:1 and 18:1 alkyl-Gro showed strong activity in reducing lung metastasis number, while saturated alkyl- Gro had weaker (16:0) or no (12:0, 14:0, 18:0) effect. Multiple compounds and mechanisms are probably involved in the multiple activities of natural alkyl-Gro.

The fatty acid desaturase 3 gene encodes for different FADS3 protein isoforms in mammalian tissues.

In 2000, Marquardt et al. (A. Marquardt, H. Stöhr, K. White, and B. H. F. Weber. 2000. cDNA cloning, genomic structure, and chromosomal localization of three members of the human fatty acid desaturase family. Genomics. 66: 176-183.) described the genomic structure of the fatty acid desaturase (FADS) cluster in humans. This cluster includes the FADS1 and FADS2 genes encoding, respectively, for the Delta 5- and Delta 6-desaturases involved in polyunsaturated fatty acid biosynthesis. A third gene, named FADS3, has recently been identified but no functional role has yet been attributed to the putative FADS3 protein. In this study, we investigated the FADS3 occurrence in rat tissues by using two specific polyclonal antibodies directed against the N-terminal and C-terminal ends of rat FADS3. Our results showed three potential protein isoforms of FADS3 (75 kDa, 51 kDa, and 37 kDa) present in a tissue-dependent manner. The occurrence of these FADS3 isoforms did not depend on the mRNA level determined by real-time PCR. In parallel, mouse tissues were also tested and showed the same three FADS3 isoforms but with a different tissue distribution. Finally, we reported the existence of FADS3 in human cells and tissues but different new isoforms were identified. To conclude, we showed in this study that FADS3 does exist under multiple protein isoforms depending on the mammalian tissues. These results will help further investigations to determine the physiological function of FADS3.

1-O-alkylglycerols reduce the stimulating effects of bFGF on endothelial cell proliferation in vitro.

1-O-alkylglycerols (alkyl-Gro) are natural etherlipids with multiple biological activities. We previously demonstrated that alkyl-Gro reduce endothelial permeability. Here we showed that alkyl-Gro reduced the basic Fibroblast Growth Factor (bFGF)-stimulated endothelial cell proliferation in a concentration-dependent manner. The effects of 0.5 and 5 ng/ml bFGF on growth were completely suppressed after 72 h-treatment by 50 microM alkyl-Gro. Since bFGF greatly increased (+56%+/-15) the production of 1-O-alkyl-2-acyl-sn-glycerophosphate in alkyl-Gro-treated endothelial cells, our data suggest that the observed effects of alkyl-Gro could be mediated through PLD activation. Inhibition of bFGF-stimulated endothelial proliferation could support anti-angiogenic activity of alkyl-Gro.

Identification and characterization of recombinant and native rat myristoyl-CoA: protein N-myristoyltransferases.

Compared to other species that possess a single functional myristoyl-CoA: protein N-myristoyltransferase gene copy, human, mouse and cow possess 2 NMT genes, and more than 2 protein isoforms. In mammals, the contribution of each gene transcript to multiple protein isoform expression and enzyme activity remains unclear. In order to get new insight on their respective physiological role, we have cloned and characterized the two rat NMT cDNAs. Rat NMT1 and NMT2 cDNAs contain 1491 and 1590 nucleotides, respectively, with high identity with their mouse homologues. Polypeptide sequences exhibited 68.1% identity between NMT1 and 2. Recombinant rat NMT1 and 2 showed major immunoreactive forms at 66 and 50 kDa, although NMT2 is 33-amino acid longer than NMT1. Both proteins exhibited functional myristoyltransferase activity but NMT2 appeared to be 4-time less active than NMT1. Studies of native protein expression revealed that the level and sizes of NMT proteins greatly vary among rat tissues although NMT1 and 2 did not display tissue specific expression at the mRNA level. Altogether, these results suggest that NMT2 may contribute little to total NMT activity levels in vivo.

The 5-lipoxygenase pathway promotes pathogenesis of hyperlipidemia-dependent aortic aneurysm.

Activation of the 5-lipoxygenase (5-LO) pathway leads to the biosynthesis of proinflammatory leukotriene lipid mediators. Genetic studies have associated 5-LO and its accessory protein, 5-LO-activating protein, with cardiovascular disease, myocardial infarction and stroke. Here we show that 5-LO-positive macrophages localize to the adventitia of diseased mouse and human arteries in areas of neoangiogenesis and that these cells constitute a main component of aortic aneurysms induced by an atherogenic diet containing cholate in mice deficient in apolipoprotein E. 5-LO deficiency markedly attenuates the formation of these aneurysms and is associated with reduced matrix metalloproteinase-2 activity and diminished plasma macrophage inflammatory protein-1alpha (MIP-1alpha; also called CCL3), but only minimally affects the formation of lipid-rich lesions. The leukotriene LTD(4) strongly stimulates expression of MIP-1alpha in macrophages and MIP-2 (also called CXCL2) in endothelial cells. These data link the 5-LO pathway to hyperlipidemia-dependent inflammation of the arterial wall and to pathogenesis of aortic aneurysms through a potential chemokine intermediary route.

Natural alkylglycerols restrain growth and metastasis of grafted tumors in mice.

Alkylglycerols are natural etherlipids abundant in shark liver oil (SLO) in a diacylated form. SLO is known to have antitumor properties and was recently described as an inhibitor of tumor neovascularization. However, most studies did not discriminate between the respective activities of alkylglycerols and of fatty acids, which both have potent biological properties. In this work, a mouse model was used to investigate the antitumor effects of SLO and of alkylglycerols purified from the same source, both administered orally. We demonstrated that either pure alkylglycerols or SLO reduced the tumor growth in a similar manner, suggesting that alkylglycerols were involved in this effect. In alkylglycerol-treated mice, metastasis dissemination was reduced by 64 +/- 8%, whereas SLO effect was 30 +/- 9% below control. Purified alkylglycerols also decreased significantly plasmalogen content in tumors, whereas SLO had no such effect. Finally, we demonstrated that a 5-day treatment with alkylglycerols curtailed the presence in tumors of von Willebrand factor, a marker of endothelial cells. This result suggested an anti-angiogenic effect of alkylglycerols. In summary, alkylglycerols were shown to decrease the growth, vascularization, and dissemination of Lewis lung carcinoma tumors in mice. These findings suggest that the antitumor activity of SLO is likely mediated by the presence of alkylglycerols.

Regulation of calcium signalling by 1-O-alkylglycerols in human Jurkat T lymphocytes.

We studied the role of natural occurring 1-O-alkylglycerols on the calcium signalling in Jurkat T-cells. Alkylglycerols evoked an increase in free intracellular calcium concentration [Ca2+]i, in a dose-dependent manner. When the experiments were performed in calcium-free buffer, the alkylglycerol response on the rise of [Ca2+]i was wholly abolished compared with the one in calcium-containing buffer, suggesting that these etherlipids induce a calcium influx by the opening of Ca2+ channels. We further employed inhibitors of voltage-gated calcium channels. We observed that omega-conotoxin, a blocker of N-type voltage-activated Ca2+ channels, but not verapamil, a blocker of L-type voltage-activated Ca2+ channels, curtailed significantly the calcium rise evoked by the lipid agents. Alkylglycerols also induced plasma membrane depolarisation, known to be involved in the opening of the voltage-gated calcium channels. Our study shows that alkylglycerols increase [Ca2+]i influx in human Jurkat T-cells possibly by modulating the permeability of calcium channels.

Distinct roles of endoplasmic reticulum cytochrome b5 and fused cytochrome b5-like domain for rat Delta6-desaturase activity.

The Delta6-desaturase catalyzes key steps in long-chain polyunsaturated fatty acid biosynthesis. Although the gene coding for this enzyme has been isolated in diverse animal species, the protein structure remains poorly characterized. In this work, rat Delta6-desaturase expressed in COS-7 cells was shown to localize in the endoplasmic reticulum. As the enzyme contains an N-terminal cytochrome b5-like domain, we investigated by site-directed mutagenesis the role of this domain in the enzyme activity. The typical HPGG motif of the cytochrome b5-like domain, and particularly histidine in this motif, is required for the activity of the enzyme, whatever the substrate. Neither endogenous COS-7 cytochrome b5 nor coexpressed rat endoplasmic reticulum cytochrome b5 could rescue the activity of mutated forms of Delta6-desaturase. Moreover, when rat endoplasmic reticulum cytochrome b5 was coexpressed with wild-type desaturase, both proteins interacted and Delta6-desaturase activity was significantly increased. The identified interaction between these proteins is not dependent on the desaturase HPGG motif. These data suggest distinct and essential roles for both the desaturase cytochrome b5-like domain and free endoplasmic reticulum cytochrome b5 for Delta6-desaturase activity.

Abietoid seed fatty acid compositions--a review of the genera Abies, Cedrus, Hesperopeuce, Keteleeria, Pseudolarix, and Tsuga and preliminary inferences on the taxonomy of Pinaceae.

The seed fatty acid (FA) compositions of Abietoids (Abies, Cedrus, Hesperopeuce, Keteleeria, Pseudolarix, and Tsuga) are reviewed in the present study in conclusion to our survey of Pinaceae seed FA compositions. Many unpublished data are given. Abietoids and Pinoids (Pinus, Larix, Picea, and Pseudotsuga)-constituting the family Pinaceae-are united by the presence of several delta5-olefinic acids, taxoleic (5,9-18:2), pinolenic (5,9,12-18:3), coniferonic (5,9,12,15-1 8:4), keteleeronic (5,11-20:2), and sciadonic (5,11,14-20:3) acids, and of 14-methyl hexadecanoic (anteiso-17:0) acid. These acids seldom occur in angiosperm seeds. The proportions of individual delta5-olefinic acids, however, differ between Pinoids and Abietoids. In the first group, pinolenic acid is much greater than taxoleic acid, whereas in the second group, pinolenic acid is greater than or equal to taxoleic acid. Moreover, taxoleic acid in Abietoids is much greater than taxoleic acid in Pinoids, an apparent limit between the two subfamilies being about 4.5% of that acid relative to total FA. Tsuga spp. appear to be a major exception, as their seed FA compositions are much like those of species from the Pinoid group. In this respect, Hesperopeuce mertensiana, also known as Tsuga mertensiana, has little in common with Abietoids and fits the general FA pattern of Pinoids well. Tsuga spp. and H. mertensiana, from their seed FA compositions, should perhaps be separated from the Abietoid group and their taxonomic position revised. It is suggested that a "Tsugoid" subfamily be created, with seed FA in compliance with the Pinoid pattern and other botanical and immunological criteria of the Abietoid type. All Pinaceae genera, with the exception of Pinus, are quite homogeneous when considering their overall seed FA compositions, including delta5-olefinic acids. In all cases but one (Pinus), variations from one species to another inside a given genus are of small amplitude. Pinus spp., on the other hand, have highly variable levels of delta5-olefinic acids in their FA compositions, particularly when sections (e.g., Cembroides vs. Pinus sections) or subsections (e.g., Flexiles and Cembrae subsections from the section Strobus) are compared, although they show qualitatively the same FA patterns characteristic of Pinoids. Multicomponent analysis of Abietoid seed FA allowed grouping of individual species into genera that coincide with the same genera otherwise characterized by more classical botanical criteria. Our studies exemplify how seed FA compositions, particularly owing to the presence of delta5-olefinic acids, may be useful in sustaining and adding some precision to existing taxonomy of the major family of gymnosperms, Pinaceae.