Effect of substrate properties and phosphorus supply on facilitating the uptake of rare earth elements (REE) in mixed culture cropping systems of Hordeum vulgare, Lupinus albus and Lupinus angustifolius.

This study presents how phosphate (P) availability and intercropping may influence the migration of rare earth elements (REEs) in legume-grass associations. In a replacement model, Hordeum vulgare was intercropped with 11% Lupinus albus and 11% Lupinus angustifolius. They were cultivated on two substrates, A (pH = 7.8) and B (pH = 6.6), and treated with 1.5 g P m-2 or 3 g P m-2. Simultaneously, a greenhouse experiment was conducted to quantify carboxylate release. There, one group of L. albus and L. angustifolius was supplied with either 200 µmol L-1 P or 20 µmol L-1 P. L. albus released higher amounts of carboxylates at low P supply than L. angustifolius, while L. angustifolius showed the opposite response. Plants cultivated on substrate B accumulated substantially higher amounts of nutrients and REE, compared to substrate A. Higher P supply did not influence the leaf and stem P concentrations of H. vulgare. Addition of P decreased REE accumulation in barley monocultures on alkaline soil A. However, when H. vulgare was cultivated in mixed culture with L. angustifolius on alkaline substrate A with high P supply, the accumulation of REE in H. vulgare significantly increased. Conversely, on acidic substrate B, intercropping with L. albus decreased REE accumulation in H. vulgare. Our findings suggest a predominant effect of soil properties on the soil-plant transfer of REEs. However, in plant communities and within a certain soil environment, interspecific root interactions determined by species-specific strategies related to P acquisition in concert with the plant's nutrient supply impact REE fluxes between neighbouring plants.

Quinolizidine-Based Variations and Antifungal Activity of Eight Lupinus Species Grown under Greenhouse Conditions.

Fusarium oxysporum is an aggressive phytopathogen that affects various plant species, resulting in extensive local and global economic losses. Therefore, the search for competent alternatives is a constant pursuit. Quinolizidine alkaloids (QA) are naturally occurring compounds with diverse biological activities. The structural diversity of quinolizidines is mainly contributed by species of the family Fabaceae, particularly the genus Lupinus. This quinolizidine-based chemo diversity can be explored to find antifungals and even mixtures to address concomitant effects on F. oxysporum. Thus, the antifungal activity of quinolizidine-rich extracts (QREs) from the leaves of eight greenhouse-propagated Lupinus species was evaluated to outline promising QA mixtures against F. oxysporum. Thirteen main compounds were identified and quantified using an external standard. Quantitative analysis revealed different contents per quinolizidine depending on the Lupinus plant, ranging from 0.003 to 32.8 mg/g fresh leaves. Bioautography showed that all extracts were active at the maximum concentration (5 µg/µL). They also exhibited >50% mycelium growth inhibition. All QREs were fungistatic except for the fungicidal QRE of L. polyphyllus Lindl. Angustifoline, matrine, 13α-hydroxylupanine, and 17-oxolupanine were ranked to act jointly against the phytopathogen. Our findings constitute reference information to better understand the antifungal activity of naturally afforded QA mixtures from these globally important plants.

Lupin-Derived Bioactive Peptides: Intestinal Transport, Bioavailability and Health Benefits.

There is a renewed interest on the reliance of food-based bioactive compounds as sources of nutritive factors and health-beneficial chemical compounds. Among these food components, several proteins from foods have been shown to promote health and wellness as seen in proteins such as α/γ-conglutins from the seeds of Lupinus species (Lupin), a genus of leguminous plant that are widely used in traditional medicine for treating chronic diseases. Lupin-derived peptides (LDPs) are increasingly being explored and they have been shown to possess multifunctional health improving properties. This paper discusses the intestinal transport, bioavailability and biological activities of LDPs, focusing on molecular mechanisms of action as reported in in vitro, cell culture, animal and human studies. The potentials of several LDPs to demonstrate multitarget mechanism of regulation of glucose and lipid metabolism, chemo- and osteoprotective properties, and antioxidant and anti-inflammatory activities position LDPs as good candidates for nutraceutical development for the prevention and management of medical conditions whose etiology are multifactorial.

Untargeted Phytochemical Profile, Antioxidant Capacity and Enzyme Inhibitory Activity of Cultivated and Wild Lupin Seeds from Tunisia.

Lupin seeds can represent a valuable source of phenolics and other antioxidant compounds. In this work, a comprehensive analysis of the phytochemical profile was performed on seeds from three Lupinus species, including one cultivar (Lupinus albus) and two wild accessions (Lupinus cossentinii and Lupinus luteus), collected from the northern region of Tunisia. Untargeted metabolomic profiling allowed to identify 249 compounds, with a great abundance of phenolics and alkaloids. In this regard, the species L. cossentinii showed the highest phenolic content, being 6.54 mg/g DW, followed by L. luteus (1.60 mg/g DW) and L. albus (1.14 mg/g DW). The in vitro antioxidant capacity measured by the ABTS assay on seed extracts ranged from 4.67 to 17.58 mg trolox equivalents (TE)/g, recording the highest values for L. albus and the lowest for L. luteus. The DPPH radical scavenging activity ranged from 0.39 to 3.50 mg TE/g. FRAP values varied between 4.11 and 5.75 mg TE/g. CUPRAC values for lupin seeds ranged from 7.20 to 8.95 mg TE/g, recording the highest for L. cossentinii. The results of phosphomolybdenum assay and metal chelation showed similarity between the three species of Lupinus. The acetylcholinesterase (AChE) inhibition activity was detected in each methanolic extract analyzed with similar results. Regarding the butyrylcholinesterase (BChE) enzyme, it was weakly inhibited by the Lupinus extracts; in particular, the highest activity values were recorded for L. albus (1.74 mg GALAE/g). Overall, our results showed that L. cossentinii was the most abundant source of polyphenols, consisting mainly in tyrosol equivalents (5.82 mg/g DW). Finally, significant correlations were outlined between the phenolic compounds and the in vitro biological activity measured, particularly when considering flavones, phenolic acids and lower-molecular-weight phenolics.

Identification and Purification of Novel Low-Molecular-Weight Lupine Allergens as Components for Personalized Diagnostics.

Lupine flour is a valuable food due to its favorable nutritional properties. In spite of its allergenic potential, its use is increasing. Three lupine species, Lupinus angustifolius, L. luteus, and L. albus are relevant for human nutrition. The aim of this study is to clarify whether the species differ with regard to their allergen composition and whether anaphylaxis marker allergens could be identified in lupine. Patients with the following characteristics were included: lupine allergy, suspected lupine allergy, lupine sensitization only, and peanut allergy. Lupine sensitization was detected via CAP-FEIA (ImmunoCAP) and skin prick test. Protein, DNA and expressed sequence tag (EST) databases were queried for lupine proteins homologous to already known legume allergens. Different extraction methods applied on seeds from all species were examined by SDS-PAGE and screened by immunoblotting for IgE-binding proteins. The extracts underwent different and successive chromatography methods. Low-molecular-weight components were purified and investigated for IgE-reactivity. Proteomics revealed a molecular diversity of the three species, which was confirmed when investigated for IgE-reactivity. Three new allergens, L. albus profilin, L. angustifolius and L. luteus lipid transfer protein (LTP), were identified. LTP as a potential marker allergen for severity is a valuable additional candidate for molecular allergy diagnostic tests.

Lack of Efect of Short-term Lupin Grain Feeding on Ovulation Rate in Non-prolific Polish Mountain Ewes during the Breeding Season: Ultrasonographic and Endoscopic Assessment of Ovarian Activity.

The specific changes in antral follicle numbers and wave-like development have remained unrevealed in cyclic ewes fed high-protein, high-energy lupin grain for 6 days during the luteal phase of the estrous cycle (i.e., short-term nutritional flushing). This study was mainly conducted to determine ovarian effects of the 6-day lupin grain feeding in non-prolific Polish Mountain ewes, using transrectal ovarian ultrasonography and abdominal videoendoscopy. Estrus and ovulations were synchronized in 24 ewes with progestin-releasing intravaginal sponges for 12 days during the middle portion of the breeding season (September-October; 50.0458°N, 19.8406°E). Twenty-four ewes were assigned to three equal groups (n=8 each), including the Control group being fed the maintenance diet (i.e., hay-only), Treatment 1 receiving 500 g of lupin grain once a day, and Treatment 2 receiving 250 g of lupin grain twice a day, from days 9-14 of the synchronized estrous cycle (day 0=first ovulation of the interovulatory period studied). No differences were observed in the mean ovulation rate among the three groups of Polish Mountain ewes (P>0.05). Ovarian antral follicles emerging in the penultimate wave of the estrous cycle in Treatment 2 ewes had a longer growth phase (p <0.05) and attained a greater diameter (p <0.05) before ovulation, in comparison to those in the other two groups. A final wave of the interovulatory interval emerged ~1 day earlier in Treatment 2 than in Treatment 1 ewes (p <0.05). Nutritional supplementation with lupin grain increased the number of 3-mm follicles in Treatment 2 ewes (p <0.05). The results of this study indicated that short-term nutritional flushing with lupin grain from mid- to late luteal phase did not consistently enhance ovulatory responses in non-prolific genotypes of ewes. Although the administration of lupins altered the timing of wave emergence, ovulatory follicle diameter, or duration of different stages of the follicular lifespan, it failed to increase the number of ovulatory follicles emerging in the penultimate and final waves of the estrous cycle in non-prolific Polish Mountain sheep.

The Protective Effects of Lupine (Lupinus albus) Fruit Extract Against to Destructive Effects of Hyperglycemia in Type I Diabetic Rats.

BACKGROUND: Lupinus albus is a member of the Fabaceae family. As a natural or cultivated plant, Lupinus albus is distributed in Europe, the Balkans and Turkey, especially in Marmara and Aegean regions. The lupine is a nutritious and protective plant against diabetes. OBJECTIVE: In the present study, the effects of Lupinus albus fruits on malondialdehyde (MDA), reduced glutathione (GSH), total protein, ADEK vitamins, and cholesterol values, which are the indicators of oxidative damage and antioxidant defense. In this regard, muscle, liver, renal, and brain tissues of STZ-induced type I diabetes rats were studied. METHODS: The analyzes of ADEK vitamins and cholesterol levels in tissues were performed via Shimadzu HPLC device. The lipid peroxidation levels were measured at 532 nm in spectrophotometer. Determination of GSH was read at 412 nm against blank, and for the total protein levels Lowry method was applied. RESULTS: According to the results obtained, it was determined that among the rats with induced type I diabetes, the group applied lupine fruit extract was found to have increased GSH level and decreased MDA levels in all the tissues. The protein values were increased in liver tissues but decreased in the other tissues. The level of vitamins was significantly increased in almost all the tissues in the diabetic group. CONCLUSION: In the present study, it was shown that the lupine reduced the devastating effects of type I diabetes by decreasing the fasting blood glucose and lipid peroxidation values and increasing the glutathione level in comparison to the diabetic group.

Effect of the acute and chronic administration of Lupinus albus ß-conglutin on glycaemia, circulating cholesterol, and genes potentially involved.

Constituents of lupin seeds, like γ-conglutin and lupanine, have gained attention as potential complementary treatments for dysglycaemia management. Notwithstanding, the effect of other lupin components on carbohydrate metabolism, including ß-conglutin protein, has received little attention. Here, we investigated the influence of the acute and chronic administration of ß-conglutin on glycaemia modulation in normal and streptozotocin induced-to-diabetes rats. We analysed the liver transcriptome modulation exerted by ß-conglutin in diabetes-induced rats using DNA microarrays to scout for potential molecular targets and pathways involved in this biological response. The acute administration of ß-conglutin reduced the incremental area under the curve of glycaemia in normal and diabetes-induced animals. In a seven-day study with diabetic animals, glycaemia increased significantly in non-treated animals but remained unchanged in animals treated with a daily dose of ß-conglutin. Total cholesterol was significantly lower at the end of the experimental period (-21.8 %, p = 0.039). The microarray and gene ontology analyses revealed several targets and pathways potentially modulated by ß-conglutin treatment, including a possible down-regulation of Jun kinase activity. Moreover, our data indicate that targets related to oxidative stress, inflammation, and estrogenic activity might orchestrate these metabolic effects. In conclusion, our findings show that ß-conglutin may help manage postprandial glycaemia and reduce cholesterol levels under the dysglycaemia stage. We identified and proposed new potential molecular targets for further research related to the mechanism of action of ß-conglutin.

The Effect of Fermentation with Kefir Grains on the Physicochemical and Antioxidant Properties of Beverages from Blue Lupin (Lupinus angustifolius L.) Seeds.

Plant derived fermented beverages have recently gained consumers' interest, particularly due to their intrinsic functional properties and presence of beneficial microorganisms. Three variants containing 5%, 10%, and 15% (w/w) of sweet blue lupin (Lupinus angustifolius L. cv. "Boregine") seeds were inoculated with kefir grains and incubated at 25 °C for 24 h. After processing, beverages were stored in refrigerated conditions (6 °C) for 21 days. Changes in microbial population, pH, bioactive compounds (polyphenolics, flavonoids, ascorbic acid), reducing sugars, and free amino acids were estimated. Additionally, viscosity, firmness, color, and free radicals scavenging properties were determined. Results showed that lactic acid bacteria as well as yeast were capable of growing well in the lupin matrix without any supplementation. During the process of refrigeration, the viability of the microorganisms was over the recommended minimum level for kefir products. Hydrolysis of polysaccharides as well as increase of free amino acids was observed. As a result of fermentation, the beverages showed excellent DPPH, ABTS+·, ·OH, and O2- radicals scavenging activities with a potential when considering diseases associated with oxidative stress. This beverages could be used as a new, non-dairy vehicle for beneficial microflora consumption, especially by vegans and lactose-intolerant consumers.

Proteomic Characterisation of Lupin (Lupinus angustifolius) Milk as Influenced by Extraction Techniques, Seed Coat and Cultivars.

Lupin seeds are rich in proteins and other essential ingredients that can help to improve human health. The protein contents in both whole and split seeds of two lupin cultivars (Mandleup and PBA Jurien) were used to produce the lupin milk using the cheesecloth and centrifuge method. Proteins were extracted from the lupin milk using thiourea/urea solubilization. The proteins were separated by a two-dimensional polyacrylamide gel electrophoresis and then identified with mass spectrometry. A total of 230 protein spots were identified, 60 of which showed differential abundances. The cheesecloth separation showed protein extractability much better than that of the centrifuge method for both the cultivars. The results from this study could offer guidance for future comparative analysis and identification of lupin milk protein and provide effective separation technique to determine specific proteins in the cheese-making process.

Assessment of the Multifunctional Behavior of Lupin Peptide P7 and Its Metabolite Using an Integrated Strategy.

LTFPGSAED (P7) is a multifunctional hypocholesterolemic and hypoglycemic lupin peptide. While assessing its angiotensin-converting enzyme (ACE) inhibitory activity, it was more effective in intestinal Caco-2 cells (IC50 of 13.7 µM) than in renal HK-2 cells (IC50 of 79.6 µM). This discrepancy was explained by the metabolic transformation mediated by intestinal peptidases, which produced two main detected peptides, TFPGSAED and LTFPG. Indeed LTFPG, dynamically generated by intestinal dipeptidyl peptidase IV as well as its parent peptide P7 were linearly absorbed by mature Caco-2 cells. An in silico study demonstrated that the metabolite was a better ligand of the ACE enzyme than P7. These results are in agreement with an in vivo study, previously performed by Aluko et al., which has shown that LTFPG is an effective hypotensive peptide. Our work highlights the dynamic nature of bioactive food peptides that may be modulated by the metabolic activity of intestinal cells.

Fatty Acid Composition, Functional Group Analysis and Antioxidant Activity of Nymphia alba and Lupinus polyphyllus Seed Extracts.

Seed extracts of Nymphia alba Linn. and Lupinus polyphyllus Lindl. were analyzed for fatty acid composition, functional group analysis and antioxidant activity. The petroleum ether extract of seeds were found dominant in unsaturated fatty acids with oleic acid (39.9%) and linoleic acid (29.6%) in L. polyphyllus and linoleic (37.5%) and oleic acid (10.9%) in N. alba. All the defatted seed extracts of N. alba and L. polyphyllus found to have powerful DPPH, ABTS, H2O2 and NBT antioxidant radical scavenging activity with reference to butylated hydroxy toluene (BHT). The defatted seed extracts were further analyzed with functional group analysis through FTIR found to contain numerous functional groups which may be responsible for their antioxidant activity.

Effect of Ultrasound Application on Protein Yield and Fate of Alkaloids during Lupin Alkaline Extraction Process.

The objective of this work is to elucidate the fate of quinolizidine alkaloids (QA) during the lupin protein extraction process assisted with ultrasound and the evaluation of the nutritional and functional properties of the protein fraction. Proximal characterization, concentration of anti-nutritional compounds, amino acid profile and protein solubility profile of flours from three lupin species were (L. albus, L. angustifolius and L. mutabilis) assessed. The result showed a significant difference (p < 0.05) in protein concentration, fat, total alkaloids and particle size between the three species flours. Based on these parameters, the most different Lupinus species (L. mutabilis and L. angustifolius) were chosen to study the behavior of the protein fraction in terms of functionality, composition and resistance to thermal treatments. The results obtained for L. mutabilis described the ultrasound effect as beneficial for protein yield (14% more than control), QA reduction from bagasse (81% less than control) and protein isolate production (50% less than control). On the other hand, L. angustifolius was more resistant to the ultrasound effect with no significant difference between treatments (10 and 15 min) and control but with the lower toxicity and better amino acid score. These results will be useful to design processes to assist in the objective of meeting the future protein demand of the population.

Pollen and vegetative secondary chemistry of three pollen-rewarding lupines.

PREMISE: Optimal defense theory predicts that selection should drive plants to disproportionally allocate resources for herbivore defense to tissues with high fitness values. Because pollen's primary role is the transport of gametes, plants may be expected to defend it from herbivory. However, for many animal-pollinated plants, pollen serves a secondary role as a pollinator reward. These dual roles may present a conflict between selection to defend pollen from herbivores and selection to reward pollinators. Here, we investigate whether pollen secondary chemistry in three pollen-rewarding Lupinus species better reflects the need to defend pollen or reward pollinators. METHODS: Lupinus (Fabaceae) species are nectarless, pollen-rewarding, and produce defensive quinolizidine and/or piperidine alkaloids throughout their tissues. We used gas chromatography to identify and quantitate the alkaloids in four aboveground tissues (pollen, flower, leaf, stem) of three western North American lupines, L. argenteus, L. bakeri, and L. sulphureus, and compared alkaloid concentrations and composition among tissues within individuals. RESULTS: In L. argenteus and L. sulphureus, pollen alkaloid concentrations were 11-35% of those found in other tissues. We detected no alkaloids in L. bakeri pollen, though they were present in other tissues. Alkaloid concentrations were not strongly correlated among tissues within individuals. We detected fewer alkaloids in pollen compared to other tissues, and pollen contained no unique alkaloids. CONCLUSIONS: Our results are consistent with the hypothesis that, in these pollen-rewarding species, pollen secondary chemistry may reflect the need to attract and reward pollinators more than the need to defend pollen from herbivory.

Characterization of polyphenols in Australian sweet lupin (Lupinus angustifolius) seed coat by HPLC-DAD-ESI-MS/MS.

Seeds of the legume lupin (Lupinus spp.) are becoming increasingly important as human food. The seed coat, at ~25% of the whole seed of Lupinus angustifolius (Australian sweet lupin, ASL), is the main by-product of lupin kernel flour production. The primary market for lupin seed coat is low value feed with very limited use in foods. In this study, seed coats of six ASL commercial varieties from two growing sites were sampled for identification and quantification of polyphenols using a high-performance liquid chromatography (HPLC) with diode array detector (DAD) and coupled with a triple quadrupole mass spectrometer which equipped with electrospray ionization source (ESI-MS/MS). Three flavones (apigenin-7-O-ß-apiofuranosyl-6,8-di-C-ß-glucopyranoside, vicenin 2, and apigenin-7-O-ß-glucopyranoside), one isoflavone (genistein) and one dihydroflavonol derivative (aromadendrin-6-C-ß-d-glucopyranosyl-7-O-[ß-D-apiofuranosyl-(1 → 2)]-O-ß-D-glucopyranoside), and several hydroxybenzoic and hydroxycinnamic acid derivatives were identified. Considerable variations in levels of individual polyphenols were found but apigenin-7-O-ß-apiofuranosyl-6,8-di-C-ß-glucopyranoside was the predominant polyphenol in all samples accounting for 73.08-82.89% of the total free polyphenols. These results suggest that ASL seed coat could be valuable dietary source of polyphenols.

Lupin seed hydrolysate promotes G-protein-coupled receptor, intracellular Ca2+ and enhanced glycolytic metabolism-mediated insulin secretion from BRIN-BD11 pancreatic beta cells.

Lupin seed proteins have been reported to exhibit hypoglycaemic effects in animals and humans following oral administration, however little is known about its mechanism of action. This study investigated the signalling pathway(s) responsible for the insulinotropic effect of the hydrolysate obtained from lupin (Lupinus angustifolius L.) seed extracts utilizing BRIN-BD11 ß-cells. The extract was treated with digestive enzymes to give a hydrolysate rich in biomolecules ≤7 kDa. Cells exhibited hydrolysate induced dose-dependent stimulation of insulin secretion and enhanced intracellular Ca2+ and glucose metabolism. The stimulatory effect of the hydrolysate was potentiated by depolarizing concentrations of KCl and was blocked by inhibitors of the ATP sensitive K+ channel, Gαq protein, phospholipase C (PLC) and protein kinase C (PKC). These findings reveal a novel mechanism for lupin hydrolysate stimulated insulin secretion via Gαq mediated signal transduction (Gαq/PLC/PKC) in the ß-cells. Thus, lupin hydrolysates may have potential for nutraceutical treatment in type 2 diabetes.

Narrow-leafed lupin (Lupinus angustifolius L.) seed ß-conglutins reverse the induced insulin resistance in pancreatic cells.

Insulin resistance (IR) is the main contributor to the development of type 2 diabetes. In this study, we have purified recombinant ß-conglutin proteins (rß1 to rß4, and rß6) from narrow-leafed lupin (NLL) by using affinity chromatography. The objective of this study was to evaluate the capacity of these ß-conglutins to improve the IR state using ex vivo and in vitro systems. rß1, rß3, and rß6 produced lower levels of pro-inflammatory mediator nitric oxide (about -7-fold in all cases), up-regulated mRNA expression levels of IRS-1 (+201, +173, +192%) and Glut-4 (+286, +121, +147%), increased levels of p85-PI3K (+188, +187, +137-fold) and Glut-4 (+503, +548, +515-fold) proteins, higher phosphorylation levels of the insulin signalling pathway activator p-IRS-1 and downstream mediators such as p-Akt, p-Cbl, and p-caveolin, and improved glucose uptake in insulin resistant (IR-C) culture cells. ß-conglutin proteins were able to suppress the oxidative stress produced by insulin-induced resistance on PANC-1 control (C) cells by strongly reducing the protein oxidative carbonylation induced by ROS and balancing the metabolic homeostasis in IR-C cells through regulation of mRNA expression. At the same time, ß-conglutins are able to reduce the levels of the pro-inflammatory mediator nitric oxide and promote the anti-oxidative capacity of cells by increasing the levels of reduced glutathione. These results suggest NLL ß-conglutins might play a fundamental role as functional food components, since ß-conglutins' nutraceutical properties could enhance the effectiveness of dietary improvement of type 2 diabetes complications.

Differentiation of Adsorptive and Viscous Effects of Dietary Fibres on Bile Acid Release by Means of In Vitro Digestion and Dialysis.

To explain the cholesterol-reducing effects of dietary fibres, one of the major mechanisms proposed is the reduced reabsorption of bile acids in the ileum. The interaction of dietary fibres with bile acids is associated with their viscous or adsorptive effects. Since these fibre characteristics are difficult to investigate in vivo, suitable in vitro methodologies can contribute to understanding the mechanistic principles. We compared the commonly used centrifugal approach with a modified dialysis method using dietary fibre-rich materials from different sources (i.e., barley, citrus, lupin, and potato). Digestion was simulated in vitro with oral, gastric, and small intestinal digestion environments. The chyme was dialysed and released bile acids were analysed by high-performance liquid chromatography. The centrifugation method showed adsorptive effects only for cholestyramine (reference material) and a high-fibre barley product (1.4 µmol taurocholic acid/100 mg dry matter). Alternatively, the dialysis approach showed higher values of bile acid adsorption (2.3 µmol taurocholic acid/100 mg dry matter) for the high-fibre barley product. This indicated an underestimated adsorption when using the centrifugation method. The results also confirmed that the dialysis method can be used to understand the influence of viscosity on bile acid release. This may be due to entrapment of bile acids in the viscous chyme matrix. Further studies on fibre structure and mechanisms responsible for viscous effects are required to understand the formation of entangled networks responsible for the entrapment of the bile acids.

Yellow lupin (Lupinus luteus L.) polysaccharides: Antioxidant, immunomodulatory and prebiotic activities and their structural characterisation.

Yellow lupin polysaccharides (YLP-1, YLP-2 and YLP-3) were isolated from the whole seeds of Lupinus luteus L. Their antioxidant activities were evaluated by ABTS+ and hydroxyl radical scavenging, and Fe2+ chelating assays. Immunostimulatory activities were measured by their ability to activate macrophages to produce TNF-α and NO. Four strains of probiotic bacteria were used to measure their prebiotic activities. YLP-2 with largest galactose content displayed the best activity amongst the three isolated polysaccharides. NMR and FT-IR spectroscopic methods have revealed that YLPs contain galactans and galactomannans which are linked with ß-(1,4) glycosidic bond in the main chain. The side chain Galp unit of galactomannan is connected to the main chain Manp by α-(1,6) linkage. The results presented in this paper strongly suggest that YLPs display significant antioxidant, immunostimulatory and prebiotic activities and hence hold great potential as nutraceutical and functional agents.

Influence of root exudation of white lupine (Lupinus albus L.) on uranium phytoavailability in a naturally uranium-rich soil.

Mechanisms of uranium (U) transfer from soil to plants remain poorly understood. The kinetics of supply of U to the soil solution from solid phases could be a key point to understand its phytoavailability and implications for environmental risk assessment. Root activity, particularly the continuous release of organic acids in the rhizosphere, could have an effect on this supply. We tested the impact of citrate exudation by roots of Lupinus albus, either P-sufficient (P+) or P-deficient (P-), on the phytoavailability of U from a naturally contaminated soil (total content of 413 mg U kg-1) using a rhizotest design. Combined effects of P (P-/P+ used to modulate plant physiology) and citrate (model exudate) on the solubilization of U contained in the soils were tested in closed reactors (batch). The batch experiment showed the existence of a low U available pool (0.4% total U) and high accessibility (kd' around 20 L kg-1) which was not significantly affected by P treatment or citrate concentrations. Analysis of U, Fe, Ca, P and citrate concentrations in the batches suggested a complex combination of mechanisms and factors including desorption, resorption, precipitation, co-sorption. On rhizotest, L. albus plants extracted 0.5-0.75% of the total U and between 25 and 40% of the estimated available U present in the rhizotest in 5 days. Uranium accumulation at the whole plant level (20 mg U kg-1d.w., shoot to root ratio around 10-3) seemed to be dependent neither on the plant P nutrition status nor citrate exudation level, possibly in relation with the equivalent accessibility of U whatever the growth conditions. Yet differential translocation to shoots seemed to be positively correlated to citrate exudation.