Echium

Abstract: The pyrrolizidine alkaloids previously identified in floral honey attributed to Echium vulgare (Boraginaceae) have been detected (8000-14 000 ppm) in pure pollen collected from the anthers of Echium vulgare. Pyrrolizidine alkaloids and/or their N-oxides were isolated from the aqueous acid extracts of pollen by use of strong cation-exchange, solid-phase extraction and identified by liquid chromatographic/mass spectrometric (LCMS) analysis. The pyrrolizidine alkaloids in the pollen are present mainly as the N-oxides. In addition to seven previously described pyrrolizidine alkaloids and/or their N-oxides (echimidine, acetylechimidine, uplandicine, 9-O-angelylretronecine, echiuplatine, leptanthine, and echimiplatine), one unidentified (echivulgarine), but previously found in honey, and two previously undescribed (vulgarine and 7-O-acetylvulgarine) pyrrolizidine alkaloids and/or their N-oxides were identified in the pollen. Tentative structures for these unidentified pyrrolizidine alkaloids are proposed on the basis of the mass spectrometric data and biogenetic considerations. The implications of these results for identifying the source and subsequent concentrations of pyrrolizidine alkaloids in honeys and commercial bee pollen are briefly discussed.

Abstract: Echium oil (EO) is a vegetable oil in which percentages of stearidonic acid (STA, 18:4n-3) often exceed those of its n-6 series equivalent γ-linolenic acid (GLA, 18:3n-6). Stearidonic acid is elongated to 20:4n-3 in fish cell cultures, suggesting that EO could be included in diets for marine fish to increase tissue 20:4n-3 and 20:3n-6 and, thereby, modulate eicosanoid metabolism. Thus, the present study aimed to test the hypotheses that dietary EO would increase tissue 20:4n-3 and 20:3n-6 and modulate immune function and eicosanoid production in juvenile Atlantic cod (Gadus morhua L.) fed a diet where fish oil (FO) was replaced by EO. Duplicate groups of juvenile cod (initial weight ca. 4 g) were fed for 18 weeks on fish meal-based diets (55% protein and 16% lipid) that differed in oil source (FO or EO). There were no significant differences in growth and feed efficiency, hepato-somatic index, percentages of liver and flesh lipids and lipid class compositions for cod fed FO and EO. Percentages of 18:4n-3, 18:3n-6 and 20:3n-6 in the total lipids of flesh and liver were higher, and percentages of 20:5n-3 and 20:4n-6 were both lower in fish fed EO than in those given FO. In flesh, the increased 18:3n-6 and 18:4n-3 were primarily located in phosphatidylcholine and, to a lesser extent, phosphatidylethanolamine, whereas 20:3n-6 concentration was highest in phosphatidylinositol. Desaturation of 18:3n-3 (to tetraene products) and 20:5n-3 to 22:6n-3 in hepatocytes was very low but was increased by dietary EO. Echium oil significantly decreased the production of prostaglandin F from gill cells stimulated with calcium ionophore A23187, and reduced head kidney macrophage activity, but had no effect on serum lysozyme activity or basic haematology. In conclusion, dietary EO may have beneficial effects on some immune parameters including eicosanoid metabolism in marine fish although this may be primarily because of decreased 20:4n-6 rather than increasing tissue levels of 20:3n-6 or 20:4n-3.

Abstract: 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.

Abstract: Genome sizes for 127 Macaronesian endemic angiosperms from 69 genera and 32 families were estimated using propidium iodide flow cytometry. Only about 30-fold variation in 1C-values was found, ranging from 0.32 pg in Echium bonnetii to 9.52 pg in Scilla dasyantha. Taxa with very small DNA amounts (1C ≤ 1.4 pg) were the most dominant group (71.7%), whereas the frequency of other categories was much lower (18.9% and 9.4% in taxa with small (1.41–3.50 pg) and intermediate 1C-values (3.51–14.00 pg), respectively). Comparisons of average C- and Cx-values between Macaronesian endemics and non-Macaronesian representatives always revealed significantly smaller amounts in the former group at various taxonomic levels (genus, family, major phylogenetic lineage). Potential relationship between nuclear DNA content and insular burst of speciation is suggested owing to the marked prevalence of very small genomes among angiosperms that underwent rapid adaptive radiation. Merging all the genome size data on Macaronesian angiosperms available shows that this flora represents the best covered plant assemblage from the phytogeographic point of view.