Fatty acid profiles from forty-nine plant species that are potential new sources of γ-linolenic acid

Antimicrobial and Antioxidant Properties of Total Polyphenols of Anchusa italica Retz

Anchusa italica Retz has been used for a long time in phytotherapy. The aim of the present study was to determine the antioxidant and antibacterial activities of extracts from the leaves and roots of Anchusa italica Retz. We first determined the content of phenolic compounds and flavonoids using Folin-Ciocalteu reagents and aluminum chloride (AlCl₃). The antioxidant activity was determined using three methods: reducing power (FRAP), 2.2-diphenyl-1-picrylhydrazyl (DPPH), total antioxidant capacity (TAC). The antimicrobial activity was investigated against four strains of Escherichia coli, two strains of Klebsiella pneumoniae and coagulase-negative Staphylococcus, and one fungal strain of Candida albicans. The results showed that the root extract was rich in polyphenols (43.29 mg GAE/g extract), while the leave extract was rich in flavonoids (28.88 mg QE/g extract). The FRAP assay showed a strong iron reduction capacity for the root extract (IC₅₀ of 0.11 µg/mL) in comparison to ascorbic acid (IC₅₀ of 0.121 µg/mL). The DPPH test determined an IC₅₀ of 0.11 µg/mL for the root extract and an IC₅₀ of 0.14 µg/mL for the leaf extract. These values are low compared to those for ascorbic acid (IC₅₀ of 0.16 µg/mL) and BHT (IC₅₀ 0.20 µg/mL). The TAC values of the leaf and root extracts were 0.51 and 0.98 mg AAE/g extract, respectively. In vitro, the extract showed inhibitory activity against all strains studied, with diameters of zones of inhibition in the range of 11.00-16.00 mm for the root extract and 11.67-14.33 mm for the leaf extract. The minimum inhibitory concentration was recorded for the leaf extract against E. coli (ATB:57), corresponding to 5 mg/mL. Overall, this research indicates that the extracts of Anchusa italica Retz roots and leaves exert significant antioxidant and antibacterial activities, probably because of the high content of flavonoids and polyphenols.

Fatty acid composition in seeds of holoparasitic Orobanchaceae from the Caucasus region: Relation to species, climatic conditions and nutritional value

The specialization of parasitic plants from the Orobanchaceae family to the heterotrophic lifestyle caused several morphological, physiological and molecular changes. One of the adaptations to the parasitic lifestyle is the production of a large number of the smallest seeds in world flora, also called "dust-seeds". Seeds of 34 holoparasitic species from the Cistanche, Orobanche, Phelipanche, and Phelypaea genera were collected in the Caucasus region (54 samples) and their fatty acid content and compositions analysed. Of these seeds, 28 were investigated for the first time, and 12 are endemic to the Caucasus (one of the most important biodiversity hotspots in the world). The influence of different hosts, populations, habitats, and climatic conditions on the fatty acid content and composition, as well as some connections of taxonomic classification are discussed. The fatty acid content in the species varied between 0.9 and 42.5%, and showed quantitative differences at generic and infrageneric levels, while displaying uniform fatty acid composition. Thirteen fatty acids were identified, of which nine were undescribed for Orobanchaceae. The fatty acid composition of the Orobanchaceae seeds represented a mixture of saturated fatty acids (SFAs) (average 7.8%) and unsaturated fatty acids (UFAs) (average 92.2%). The fatty acid content in the Orobanchaceae seeds was directly unrelated to taxonomy, while the n-6/n-3 fatty acid ratio supported the clear separation of the Orobanche and Phelipanche genera. Orobanchaceae seeds contained mainly linoleic and oleic acids, thus they could be a potential nutritional source of the unsaturated fatty acids. Additionally, the studies confirmed the hypothesis that the degree of seed oil fatty acid unsaturation increased in colder climatic conditions, especially for the Orobanche genus.

Fatty acids as chemotaxonomic and ecophysiological traits in green microalgae (desmids, Zygnematophyceae, Streptophyta): A discriminant analysis approach

Desmids (Zygnematophyceae) are a group of poorly studied green microalgae. The aim of the present study was to identify fatty acids (FAs) that could be used as biomarkers in desmids in general, and to determine FAs as traits within different ecophysiological desmid groups. FA profiles of 29 desmid strains were determined and analysed with respect to their geographic origin, trophic preference and age of cultivation. It appeared that merely FAs present in relatively large proportions such as palmitic, linoleic, α-linolenic and hexadecatrienoic acids could be used as biomarkers for reliable categorization of this microalgal group. Linear discriminant analysis applied to three a priori defined groups of desmids, revealed clear strain-specific characteristics regarding FA distribution, influenced by climate and trophic conditions at the source sites as well as by the age of culture and growth phase. Accordingly, when considering FAs for the determination of lower taxonomic ranks we recommend using the term "trait" instead of "biomarker", as the latter designates unchangeable "fingerprint" of a specific taxon. Furthermore, despite that desmids were regarded as microalgae having stable genomes, long-term cultivation appeared to cause modifications in FA metabolic pathways, evident as a larger proportion of stearidonic acid in desmid strains cultivated over extensive time periods (>35 years).

Anchusa azurea Mill. (Boraginaceae) aerial parts methanol extract interfering with cytoskeleton organization induces programmed cancer cells death

The present study aimed to determine the chemical composition, antioxidant effects and antitumor properties of a methanol extract of Anchusa azurea Mill. (Boraginaceae) aerial parts against four tumour cell lines (MCF-7, MDA-MB-231, RKO, and R2C). The antioxidant effects were assessed by using β-carotene bleaching, 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reducing ability power (FRAP) tests. HPLC analyses revealed chlorogenic acid, catechin, caffeic acid, and astragalin as the most abundant compounds. Interesting results were obtained in the β-carotene bleaching test with IC50 values of 7.6 and 27.5 μg mL-1 after 30 and 60 min of incubation, respectively. Furthermore, the A. azurea extract protects 3T3-L1 mouse cells from oxidative stress induced by menadione and exhibits good antitumor activity, with very low toxicity. Our data indicate that the antitumor properties are due to the ability to induce programmed cancer cell death through caspase 3/7 and 9 activation and interference with the cytoskeleton dynamics.

Micropropagation and Quantification of Bioactive Compounds in Mertensia maritima (L.) Gray

The goal of this study was to establish an efficient protocol for the large-scale propagation of Mertensia maritima (L.) Gray, and evaluate the carotenoid, fatty acid, and tocopherol contents in the leaves of in vitro regenerated shoots. Surface-disinfected node and shoot tip explants were placed on semisolid Murashige and Skoog (MS) medium with 0-16 µM N⁶-benzyladenine (BA), kinetin, (KN), and thidiazuron (TDZ) alone, or in combination with, 1 or 2 µM α-naphthaleneacetic acid (NAA). Of the three different cytokinins employed, TDZ elicited the best results for axillary shoot proliferation. A maximum frequency of shoot initiation above 84%, with a mean of 8.9 and 4.8 shoots per node and shoot tip, respectively, was achieved on the culture medium supplemented with 4 µM TDZ. A combination of TDZ + NAA significantly increased the percentage of multiple shoot formation and number of shoots per explant. The best shoot induction response occurred on MS medium with 4 µM TDZ and 1 µM NAA. On this medium, the node (93.8%) and shoot tip (95.9%) explants produced an average of 17.7 and 8.6 shoots, respectively. The highest root induction frequency (97.4%) and number of roots per shoot (25.4), as well as the greatest root length (4.2 cm), were obtained on half-strength MS medium supplemented with 4 µM indole-3-butyric acid (IBA). The presence of six carotenoids and α-tocopherol in the leaf tissues of M. maritima was confirmed by HPLC. Gas chromatography-mass spectrometry analysis confirmed the presence of 10 fatty acids, including γ-linolenic acid and stearidonic acid in the leaf tissues of M. maritima. All-E-lutein (18.49 μg g^-1 fresh weight, FW), α-tocopherol (3.82 μg g^-1 FW) and α-linolenic acid (30.37%) were found to be the significant compounds in M. maritima. For the first time, a successful protocol has been established for the mass propagation of M. maritima with promising prospects for harnessing its bioactive reserves.

Trehalose Contributes to Gamma-Linolenic Acid Accumulation in Cunninghamella echinulata Based on de Novo Transcriptomic and Lipidomic Analyses

Gamma-linolenic acid (GLA) is essential for the well-being of humans and other animals. People may lack GLA because of aging or diseases, and thus, dietary supplements or medical reagents containing GLA-enriched lipids are in demand. Cunninghamella echinulata is a potential GLA-producing strain. Interestingly, we found that the GLA content of C. echinulata FR3 was up to 21% (proportion of total lipids) when trehalose was used as a carbon source, significantly higher than the 13% found when glucose was used. Trehalose is quite common and can be accumulated in microorganisms under stress conditions. However, little information is available regarding the role of trehalose in GLA synthesis and accumulation. Our study aimed to understand how the metabolism of C. echinulata responds to trehalose as a carbon source for GLA and lipid biosynthesis. We profiled the major sugars, fatty acids, phospholipids, and gene transcripts of C. echinulata FR3 grown in trehalose medium with glucose as a control by de novo transcriptomics, lipidomics, and other methods. The results showed that trehalose could influence the expression of desaturases and that the GLA proportion increased because of delta-6 desaturase upregulation. The increased GLA was transferred to the extracellular environment through the active PI ion channel, which prefers polyunsaturated acyl chains. At the same time, trehalose might prevent GLA from peroxidation by forming a trehalose-polyunsaturated fatty acid (PUFA) complex. Our study provides new insights into the functions of trehalose in GLA accumulation.

Effects of global change factors on fatty acids and mycosporine-like amino acid production in Chroothece richteriana (Rhodophyta)

Under natural conditions, Chroothece richteriana synthesizes a fairly high proportion of fatty acids. However, nothing is known about how environmental changes affect their production, or about the production of protective compounds, when colonies develop under full sunshine with high levels of UV radiation. In this study, wild colonies of C. richteriana were subjected to increasing temperature, conductivity, ammonium concentrations and photosynthetically active radiation (PAR), and UV radiations to assess the potential changes in lipid composition and mycosporine-like amino acids (MAAs) concentration. The PERMANOVA analysis detected no differences for the whole fatty acid profile among treatments, but the percentages of α-linolenic acid and total polyunsaturated fatty acids increased at the lowest assayed temperature. The percentages of linoleic and α-linolenic acids increased with lowering temperature. γ-linolenic and arachidonic acids decreased with increasing conductivity, and a high arachidonic acid concentration was related with increased conductivity. The samples exposed to UVB radiation showed higher percentages of eicosapentaenoic acid and total monounsaturated fatty acids, at the expense of saturated fatty acids. MAAs accumulation increased but not significantly at the lowest conductivity, and also with the highest PAR and UVR exposure, while ammonium and temperature had no effect. The observed changes are probably related with adaptations of both membrane fluidity to low temperature, and metabolism to protect cells against UV radiation damage. The results suggest the potential to change lipid composition and MAAs concentration in response to environmental stressful conditions due to climate change, and highlight the interest of the species in future research about the biotechnological production of both compound types.

Sardinian Boraginaceae are new potential sources of gamma-linolenic acid

The aim of this work was to establish the richness in γ-linolenic acid (GLA, 18:3n6) and stearidonic acid (SDA, 18:4n3) of several Sardinian Boraginaceae species. To this end, seeds of selected species were collected from their natural habitats and analysed. The highest GLA contents were found in the seed oils of two endemic Borago taxa, i.e. B. morisiana (24.4 and 24.6% GLA of total fatty acids for samples from San Pietro Island and Sardinia Island, respectively), and 22.9% GLA for B. pygmaea. Both Borago species contained more GLA than B. officinalis collected in the same ecosystems. SDA was found in significant amounts in Echium plantagineum seed oil from the Lattias Mountains (15% SDA of total fatty acids). It is notable that both Borago GLA-rich species are under threat of extinction, thus revealing the importance of the preservation of the natural Sardinian ecosystems for endangered species and human health.

Consumption of Buglossoides arvensis seed oil is safe and increases tissue long-chain n-3 fatty acid content more than flax seed oil - results of a phase I randomised clinical trial

Enrichment of tissues with ≥20-carbon n-3 PUFA like EPA is associated with positive cardiovascular outcomes. Stearidonic acid (SDA; 18 : 4n-3) and α-linolenic acid (ALA; 18 : 3n-3) are plant-derived dietary n-3 PUFA; however, direct comparisons of their impact on tissue n-3 PUFA content are lacking. Ahiflower^® oil extracted from Buglossoides arvensis seeds is the richest known non-genetically modified source of dietary SDA. To investigate the safety and efficacy of dietary Ahiflower oil, a parallel-group, randomised, double-blind, comparator-controlled phase I clinical trial was performed. Diets of healthy subjects (n 40) were supplemented for 28 d with 9·1 g/d of Ahiflower (46 % ALA, 20 % SDA) or flax seed oil (59 % ALA). Blood and urine chemistries, blood lipid profiles, hepatic and renal function tests and haematology were measured as safety parameters. The fatty acid composition of fasting plasma, erythrocytes, polymorphonuclear cells and mononuclear cells were measured at baseline and after 14 and 28 d of supplementation. No clinically significant changes in safety parameters were measured in either group. Tissue ALA and EPA content increased in both groups compared with baseline, but EPA accrual in plasma and in all cell types was greater in the Ahiflower group (time × treatment interactions, P ≤ 0·01). Plasma and mononuclear cell eicosatetraenoic acid (20 : 4n-3) and docosapentaenoic acid (22 : 5n-3) content also increased significantly in the Ahiflower group compared with the flax group. In conclusion, the consumption of Ahiflower oil is safe and is more effective for the enrichment of tissues with 20- and 22-carbon n-3 PUFA than flax seed oil.

Native Oils from Apple, Blackcurrant, Raspberry, and Strawberry Seeds as a Source of Polyenoic Fatty Acids, Tocochromanols, and Phytosterols: A Health Implication

The oils from strawberry, blackcurrant, raspberry, and apple seeds were characterized by a high content of unsaturated fatty acids (90.8%, 88.6%, 94.0%, and 86.9%, resp.). Strawberry and raspberry oils had high levels of C18:2 (45.4% and 49.0%) andαC18:3 (29.0% and 33.0%, resp.). Blackcurrant oil was the richest source ofγC18:3 (18.5%) and C18:4 (3.6%). Apple oil had high levels of C18:2 (55.5%) and C18:1 (29.4%). Blackcurrant oil had 229.5 mg/100 g of tocochromanols, predominantlyγ-tocopherol (117.8 mg/100 g) andα-tocopherol (84.3 mg/100 g). Raspberry oil was rich inγ-,α-, andδ-tocopherol (193.5; 65.6; and 32.2 mg/100 g, resp.). Strawberry oil containedγ- andδ-tocopherol, 49.0 and 6.1 mg/100 g, respectively. Apple contained all isomers ofα-,β-,γ-, andδ-tocopherols at 41.7, 62.7, 13.6, and 21.8 mg/100 g, respectively. The level of tocotrienols in the analysed oils ranged from 0.85 to 6.73 mg/100 g. Ten different phytosterols were found in the tested oils. The richest sources of phytosterols were blackcurrant oil (6824.9 μg/g) followed by raspberry (5384.1 μg/g), strawberry (4643.1 μg/g), and apple oil (3460.0 μg/g). The dominant compound in the analysed oils was sitosterol, from 2630 μg/g in apple oil to 3630 μg/g in blackcurrant oil.

Effect of bioactive substances found in rapeseed, raspberry and strawberry seed oils on blood lipid profile and selected parameters of oxidative status in rats

Rapeseed, strawberry and raspberry seed oils are a rich source of polyunsaturated fatty acids and antioxidants such as tocols, bioflavonoids and phytosterols. The aim of the study was to determine changes in the blood lipid profile of rats fed with rapeseed, strawberry and raspberry seed oils and their effects on selected parameters of oxidative status. The experiment was carried out on male Wistar rats. The oils were administered by oral gavage for 5 weeks once daily at the dose of about 0.8 ml per rat. Blood samples were taken before and after supplementation period. The activity of superoxide dismutase (SOD) and glutathione peroxidase (cGPx) was assessed in erythrocytes and contents of triglycerides (TG), total cholesterol, low-density fraction of cholesterol (LDL) and high-density fraction of cholesterol (HDL) were assessed in plasma. The experiment shows that oils supplemented in the diet for 5 weeks had no significant effect on the level of triglyceride (TG), total cholesterol as well as HDL and LDL fractions. Reduced activity of cGPX and SOD in the group of rats receiving raspberry and strawberry seed oils suggests that these native oils may contribute to oxidative stability (improves antioxidant status). Thus, strawberry and raspberry seed oils can be considered as special biological oils, which constitute potential nutraceuticals reducing oxidative stress.

Dietary omega-3 PUFA and health: stearidonic acid-containing seed oils as effective and sustainable alternatives to traditional marine oils

The daily consumption of dietary omega-3 PUFA is recommended by governmental agencies in several countries and by a number of health organizations. The molecular mechanisms by which these dietary PUFA affect health involve the enrichment of cellular membranes with long-chain 20- and 22-carbon omega-3 PUFA that impacts tissues by altering membrane protein functions, cell signaling, and gene expression profiles. These changes are recognized to have health benefits in humans, especially relating to cardiovascular outcomes. Cellular membrane enrichment and health benefits are associated with the consumption of long-chain omega-3 PUFA found in marine oils, but are not generally linked with the consumption of alpha-linolenic acid, the 18-carbon omega-3 PUFA found in plant seed oils. However, the supply of omega-3 PUFA from marine sources is limited and may not be sustainable. New plant-derived sources of omega-3 PUFA like stearidonic acid-soy oil from genetically modified soybeans and Ahiflower oil from Buglossoides arvensis seeds that are enriched in the 18-carbon omega-3 PUFA stearidonic acid are being developed and show promise to become effective as well as sustainable sources of omega-3 PUFA. An example of changes in tissue lipid profiles associated with the consumption of Ahiflower oil is presented in a mouse feeding study.

Searching for health beneficial n-3 and n-6 fatty acids in plant seeds

Various plant seeds have received little attention in fatty acid research. Seeds from 30 species mainly of Boraginaceae and Primulaceae were analysed in order to identify potential new sources of the n-3 PUFA α-linolenic acid (ALA) and stearidonic acid (SDA) and of the n-6 PUFA γ-linolenic acid (GLA). The fatty acid distribution differed enormously between genera of the same family. Echium species (Boraginaceae) contained the highest amount of total n-3 PUFA (47.1%), predominantly ALA (36.6%) and SDA (10.5%) combined with high GLA (10.2%). Further species of Boraginaceae rich in both SDA and GLA were Omphalodes linifolia (8.4, 17.2%, resp.), Cerinthe minor (7.5, 9.9%, resp.) and Buglossoides purpureocaerulea (6.1, 16.6%, resp.). Alkanna species belonging to Boraginaceae had comparable amounts of ALA (37.3%) and GLA (11.4%) like Echium but lower SDA contents (3.7%). Different genera of Primulaceae (Dodecatheon and Primula) had varying ALA (14.8, 28.8%, resp.) and GLA portions (4.1, 1.5%, resp.), but similar amounts of SDA (4.9, 4.5%, resp.). Cannabis sativa cultivars (Cannabaceae) were rich in linoleic acid (57.1%), but poor in SDA and GLA (0.8, 2.7%, resp.). In conclusion, several of the presented plant seeds contain considerable amounts of n-3 PUFA and GLA, which could be relevant for nutritional purposes due to their biological function as precursors for eicosanoid synthesis.

Variation in bulk tissue, fatty acid and monosaccharide δ13C values between autotrophic and heterotrophic plant organs

The flowers of 23 species of grass and herb plants were collected from a mesotrophic grassland to assess natural variability in bulk, monosaccharide and fatty acid δ(13)C values from one plant community and were compared with previous analyses of leaves from the same species. The total mean bulk δ(13)C value of flower tissues was -28.1‰, and there was no significant difference between the mean δ(13)C(flower) values for grass (-27.8‰) and herb (-28.2‰) species. On average bulk δ(13)C(flower) values were 1.1‰ higher than bulk δ(13)C(leaf) values, however, the δ(13)C(flower) and δ(13)C(leaf) values of grasses did not differ between organs suggesting that carbon isotope discrimination is different in grass and herb species. The abundance of different monosaccharides abundance varied between plant types, i.e. xylose concentrations in the grass flowers were as high as 40%, compared with up to 15% in the herb species, but the general relationship δ(13)C(arabinose)>δ(13)C(xylose)>δ(13)C(glucose)>δ(13)C(galactose) which had been observed in leaves was similar in flowers (total mean δ(13)C values=-25.9‰, -27.2‰, -28.8‰ and -28.1‰, respectively). However, the average 5.4‰ depletion in the δ(13)C values of the C(16:0), C(18:2) and C(18:3) fatty acids in flowers compared to bulk tissue was significantly greater than observed for leaves. The trend C(16:0)<C(18:2)<C(18:3) previously observed in leaves was also observed in grass flowers (δ(13)C(C16:0)=-33.8‰; δ(13)C(C18:2)=-33.1‰; δ(13)C(C18:3)=-34.2‰) but not herb flowers (δ(13)C(C16:0)=-34.1‰; δ(13)C(C18:2)=-32.4‰; δ(13)C(C18:3)=-34.5‰). We conclude: (i) that the biological processes influencing carbon isotope discrimination in grass flowers are different from herbs flowers; and, (ii) that a range of post-photosynthetic fractionation effects caused the observed differences between flower and leaf δ(13)C values, especially the significant (13)C-depletion in flower fatty acid δ(13)C values.

Echium acanthocarpum hairy root cultures, a suitable system for polyunsaturated fatty acid studies and production

Background

The therapeutic and health promoting role of highly unsaturated fatty acids (HUFAs) from fish, i.e. eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) are well known. These same benefits may however be shared by some of their precursors, the polyunsaturated fatty acids (PUFAs), such as stearidonic acid (SDA, 18:4 n-3). In order to obtain alternative sources for the large-scale production of PUFAs, new searches are being conducted focusing on higher plants oils which can contain these n-3 and n-6 C18 precursors, i.e. SDA and GLA (18:3n-6, γ-linolenic acid).

Results

The establishment of the novel Echium acanthocarpum hairy root cultures represents a powerful tool in order to research the accumulation and metabolism of fatty acids (FAs) in a plant particularly rich in GLA and SDA. Furthermore, this study constitutes the first example of a Boraginaceae species hairy root induction and establishment for FA studies and production. The dominant PUFAs, 18:2n-6 (LA, linoleic acid) and 18:3n-6 (GLA), accounted for about 50% of total FAs obtained, while the n-3 PUFAs, 18:3n-3 (ALA, α-linolenic acid) and 18:4n-3 (SDA), represented approximately 5% of the total. Production of FAs did not parallel hairy root growth, and the optimal productivity was always associated with the highest biomass density during the culture period. Assuming a compromise between FA production and hairy root biomass, it was determined that sampling times 4 and 5 gave the most useful FA yields. Total lipid amounts were in general comparable between the different hairy root lines (29.75 and 60.95 mg/g DW), with the major lipid classes being triacylglycerols. The FAs were chiefly stored in the hairy roots with very minute amounts being released into the liquid nutrient medium.

Conclusions

The novel results presented here show the utility and high potential of E. acanthocarpum hairy roots. They are capable of biosynthesizing and accumulating a large range of polyunsaturated FAs, including the target GLA and SDA fatty acids in appreciable quantities.

Differentiation of Symphytum Species Using RAPD and Seed Fatty Acid Patterns

RAPD and fatty acid profiles, and α-tocoferol contents of the seeds of some Symphytum species were analyzed for their differentiation. Discriminative patterns were found in the examined species. Genotypic characteristics of three Symphytum species were experienced using 20 decamer RAPD primers. The majority of band positions varied between species. The total amplified products of 20 RAPD primers was 247 (average of 12.35 bands per primer), of which 189 bands were polymorphic, corresponding to nearly 76.1% genetic diversity. The number of bands for each RAPD primer varied from 8 (UBC320) to 18 (OPA7). The percent of polymorphic bands ranged from 45.4% (OPJ20) to 93.3% (OPA16). Major unsaturated fatty acids in the seeds were linoleic, γ-linolenic and oleic acids; α-linolenic and eicosenoic acids exhibited lower levels. Variations in quantities and total ratios of fatty acid groups, and α-tocopherol contents were also observed between the species, and the developmental stages of the seeds. Significant differences were found for the whole series of fatty acids between species, in addition to the calculated ratios ( p < 0.05). Differences were also significant for fatty acid traits between two developmental stages of the seeds of endemic S. pseudobulbosum ( p < 0.05). In some morphological descriptors of the seeds, difference was found at a significant level ( p < 0.05). Obtained data based on genetic and biochemical variations seem to be useful for molecular delimitation of Symphytum, in addition to selection of the genotypes expressing a high amount of GLA.

Comparative study of lipids in mature seeds of six Cordia species (family boraginaceae) collected in different regions of Brazil

The oil content, FA, and lipid class composition of the mature seeds of six Cordia species were analyzed. Mature seeds of each species were collected in their natural habitat from 2002 to 2004. The total lipid content varied from 1.9% to 13.2%, there being significant differences between the results found in different years for each species and between the species analyzed. The contents of FFA varied from 2.0% to 7.9% of total lipids. Neutral lipids (NL) were the largest class, making up between 89.6% and 96.4% of the total lipids; the phospholipids (PL) were the second largest class (3.0% to 8.9% of the total lipids), and the glycolipids (GL) were the smallest class (0.6 to 3.4%). The presence of GLA was determined in each class of lipids; it is predominant in the NL. Levels of GLA ranged from 1.2% to 6.8% of total seed FA. This is, to our knowledge the first study of lipid composition in seeds of species of Cordia from Brazil.

Effect of diets enriched in Δ6 desaturated fatty acids (18:3n−6 and 18:4n−3), on growth, fatty acid composition and highly unsaturated fatty acid synthesis in two populations of Arctic charr (Salvelinus alpinus L.)

This study aimed to test the hypothesis that diets containing relatively high amounts of the Delta6 desaturated fatty acids stearidonic acid (STA, 18:4n-3) and gamma-linolenic acid (GLA, 18:3n-6), may be beneficial in salmonid culture. The rationale being that STA and GLA would be better substrates for highly unsaturated fatty acid (HUFA) synthesis as their conversion does not require the activity of the reputed rate-limiting enzyme, fatty acid Delta6 desaturase. Duplicate groups of two Arctic charr (Salvelinus alpinus L.) populations with different feeding habits, that had been reported previously to show differences in HUFA biosynthetic capacity, were fed for 16 weeks on two fish meal based diets containing 47% protein and 21% lipid differing only in the added lipid component, which was either fish oil (FO) or echium oil (EO). Dietary EO had no detrimental effect on growth performance and feed efficiency, mortalities, or liver and flesh lipid contents in either population. The proportions of 18:2n-6, 18:3n-3, 18:3n-6, 18:4n-3, 20:3n-6 and 20:4n-3 in total lipid in both liver and flesh were increased by dietary EO in both populations. However, the percentages of 20:5n-3 and 22:6n-3 were reduced by EO in both liver and flesh in both strains, whereas 20:4n-6 was only significantly reduced in flesh. In fish fed FO, HUFA synthesis from both [1-(14)C]18:3n-3 and [1-(14)C]20:5n-3 was significantly higher in the planktonivorous Coulin charr compared to the demersal, piscivorous Rannoch charr morph. However, HUFA synthesis was increased by EO in Rannoch charr, but not in Coulin charr. In conclusion, dietary EO had differential effects in the two populations of charr, with HUFA synthesis only stimulated by EO in the piscivorous Rannoch morph, which showed lower activities in fish fed FO. However, the hypothesis was not proved as, irrespective of the activity of the HUFA synthesis pathway in either population, feeding EO resulted in decreased tissue levels of n-3HUFA and 20:4n-6. This has been observed previously in salmonids fed vegetable oils, and thus the increased levels of Delta6 desaturated fatty acids in EO did not effectively compensate for the lack of dietary HUFA.

Substrate specificity of acyl-Delta(6)-desaturases from Continental versus Macaronesian Echium species

Echium (Boraginaceae) species from the Macaronesian islands exhibit an unusually high level of gamma-linolenic acid (18:3n-6; GLA) and relatively low content of octadecatetraenoic acid (18:4n-3; OTA) in the seed, while the amounts of both fatty acids in their Continental (European) relatives are rather similar. We have tested the hypothesis of whether a different specificity of the acyl-Delta(6)-desaturases (D6DES) towards their respective usual substrates, linoleic acid (18:2n-6; LA) for GLA and alpha-linolenic acid (18:3n-3; ALA) for OTA, was partly responsible for this composition pattern. To this aim we have expressed in yeast the coding sequences of the D6DES genes for the Continental species Echium sabulicola, and the Macaronesian Echium gentianoides. When the yeast cultures are supplemented with the two fatty acid substrates (LA and ALA), a similar utilization of both compounds was found for the D6DES of E. sabulicola, while a preference for LA over ALA was observed for the enzyme of E. gentianoides. This substrate preference must contribute to the increased accumulation of GLA in the seeds of the Macaronesian Echium species. Comparison among the amino acid sequences of these desaturases and other related enzymes, allowed us the discussion about the possible involvement of some specific positions in the determination of substrate specificity.

Gamma-linolenic acid from Cape Verdian Boraginaceae

The distribution of gamma-linolenic acid (GLA) was studied in the seed oil of six Cape Verdian Boraginaceae. The GLA ranges from trace levels in the three Heliotropum surveyed to 22.2% on saponifiable oil in Echium stenosiphon. All Echium species had GLA percentages in their seed oil around 20%. Echium seeds yield saponifiable oil from 15.8% (E. stenosiphon) to 17.3% (E. hypertropicum).

Dietary echium oil increases plasma and neutrophil long-chain (n-3) fatty acids and lowers serum triacylglycerols in hypertriglyceridemic humans

A wealth of evidence indicates that consumption of fish or dietary fish oils containing long-chain (n-3) PUFA such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) is associated with cardiovascular benefit, including a reduction in circulating triacylglycerol concentrations and reduced mortality from coronary heart disease. Shorter-chain dietary (n-3) PUFA such as alpha-linolenic acid from vegetable oils are inefficiently converted to EPA and DHA and do not possess the hypotriglyceridemic properties attributed to fish oils. The objective of this study was to investigate the effect of dietary Echium oil, a plant oil containing the 18-carbon (n-3) PUFA stearidonic acid, on tissue fatty acid content and serum triacylglycerol concentrations in hypertriglyceridemic humans. Asymptomatic subjects with mild-to-moderate hypertriglyceridemia were enrolled in an open-labeled study. Subjects underwent a 4-wk lead-in period and were then instructed to follow the National Cholesterol Education Program Step 1 diet. Subjects (n = 11) whose serum triacylglycerol concentrations remained between 3.4 and 5.1 mmol/L (300 and 450 mg/dL) were instructed to consume 15 g of Echium oil daily for 4 wk. During the treatment period, serum triacylglycerol concentrations decreased by 21%, or 0.87 +/- 0.26 mmol/L (mean +/- SD) compared with baseline (P < 0.05); 8 of 11 subjects had a decrease in serum triacylglycerols ranging from 13 to 52% with a decrease from baseline of 30%, or 1.26 +/- 0.41 mmol/L (mean +/- SD). There were no significant changes in any other clinical laboratory variables. Concentrations of long-chain (n-3) PUFA, including EPA, increased (P < 0.05) in plasma and neutrophils when subjects consumed Echium oil. In conclusion, dietary plant oils rich in stearidonic acid are metabolized to longer-chain, more unsaturated (n-3) PUFA. These oils appear to possess hypotriglyceridemic properties typically associated with fish oils.

Occurrence and characterization of oils rich in gamma-linolenic acid (III): the taxonomical value of the fatty acids in Echium (Boraginaceae)

Fourteen species of the genus Echium (Fam. Boraginaceae) collected in the Macaronesia were surveyed in a search for high levels of gamma-linolenic acid (GLA, 18:3omega6) in the seed oil. High amounts of this fatty acid were found in all of them, ranging from 18.85% (E. pitardii var. pitardii) to 27.42% (E. gentianoides) on total seed fatty acids. The GLA content related to total seed weight was also significant, ranging from 1.26% (E. handiense) to 8.22% (E. gentianoides). In addition, considerable amounts of stearidonic acid (SA, 18:4omega3) were detected, ranging from 3.78% (E. bonnetii var. bonnetii) to 8.81% (E. pininana) on total fatty acids. Besides all the perennial species, the four herbaceous Echium taxa endemic to the Macaronesia also showed high GLA percentages. This is in contrast to the low GLA level found in continental Echium species, all of them bearing an herbaceous habit. These results are in good agreement with the available genetic data and show the ability of GLA to discriminate between Macaronesian and continental Echium species. The analysis of five other Macaronesian species belonging to plant families rich in GLA are also reported.