Anna Arnoldi

Phytoestrogens: End of a tale?

Phytoestrogens are plant‐derived hormone‐like diphenolic compounds of dietary origin that are present at high levels in plasma of subjects living in areas with low atherosclerosis and cancer incidence. The term phytoestrogen is commonly applied to the soy isoflavones genistein, daidzein and glycitein. As outlined in a previous review article in this journal by Adlercreutz and Mazur 1, these compounds are weakly estrogenic and appear to influence the cardiovascular system, the production, metabolism and biological activity of sex‐hormones, as well as malignant cell proliferation, differentiation and angiogenesis. Recently skepticism has developed concerning the true potential of phytoestrogens to beneficially modify these processes. A critical analysis of the early findings from supplementing the diet with soy protein has failed to confirm phytoestrogens as the responsible agent for beneficial cardiovascular effects, be it by way of lipid reduction, vasodilation or lipoprotein oxidation. Furthermore, contrasting data have been reported on the potential of phytoestrogens to prevent hormone‐dependent cancers (e.g. breast and prostate) and to successfully treat post‐menopausal complaints, an indication for which they are widely used. These potentially negative findings have led health authorities in several countries to suggest maximum daily intake levels for phytoestrogens. There is now growing interest in the use of soy products containing low levels of phytoestrogens and in research on other phytoestrogen free legumes such as lupin.

Nutritional and nutraceutical approaches to dyslipidemia and atherosclerosis prevention: Focus on dietary proteins.

A correct lifestyle is crucial in the primary and secondary prevention of cardiovascular disease. Innovative nutritional strategies to reduce the main risk factors have been developed including either dietary changes or consumption of specifically targeted functional foods and dietary supplements. These nutraceutical products may also provide an alternative to lipid lowering, antihypertensive, and antidiabetic drugs. Functional foods and beverages have the appearance of normal foods, but contain specific components whose activity on at least one measurable risk factor has been scientifically demonstrated. Dietary supplements, having formulations similar to drugs, allow the delivery of a bioactive ingredient in dosages that exceed those obtainable from food products. Among bioactive components, at present dietary proteins from both vegetable and animal sources are of high interest, because of their specific effects on cholesterolemia and blood pressure. Active peptides have been identified for the latter indication, whereas works is in progress in attempting to identify specific cholesterol lowering peptides.

Legumes are valuable sources of tocopherols

Grain legumes contain numerous phytochemicals useful for their nutritional or nutraceutical properties, such as tocopherols, involved in the prevention of cardiovascular disease and eye pathologies. In this work, tocopherols were quantified in soybean, chickpea, lentil, pea, common bean, broad bean, and three lupin species. In all samples, the gamma congener was the most abundant tocopherol, followed by minor quantities of alpha-tocopherol (with the exception of common bean lacking in this congener) and delta-tocopherol (with the exception of Lupinus angustifolius and Lupinus mutabilis). Beta-tocopherol and tocotrienols were never detected. Some samples of soybean, pea, white lupin and chickpea contained over 10mg/100g seeds of total tocopherols. In order to estimate the nutritional value, the vitamin E activity was calculated. Chickpea, soybean and, to a lesser extent, lupin, broad bean and pea may contribute in a relevant way to the daily intake of this vitamin.

ACE-inhibitory activity of enzymatic protein hydrolysates from lupin and other legumes.

The objective of this investigation was to compare the angiotensin converting enzyme (ACE)-inhibitory activity of the hydrolysates obtained by pepsin digestion of proteins of some legumes, such as chickpea, common bean, lentil, lupin, pea, and soybean, by using the same experimental procedure. The ACE-inhibitory activity was measured by using the tripeptide hippuryl-histidyl-leucine (HHL), as model peptide, and HPLC-DAD, as analytical method. The peptide mixtures of all legumes were active, with soybean and lupin the most efficient, with IC50 values of 224 and 226 μg/ml, respectively. Considering the promising results obtained with lupin, and aiming to identify the protein(s) that release(s) the peptides responsible for the activity, the peptides obtained from the pepsin digestion of some industrial lupin protein isolates and purified protein fractions were tested. The most active mixture, showing an IC50 value of 138 μg/ml, was obtained hydrolysing a mixture of lupin α+β conglutin.

A label‐free internal standard method for the differential analysis of bioactive lupin proteins using nano HPLC‐Chip coupled with Ion Trap mass spectrometry

Quantitative proteomics based on MS is useful for pointing out the differences in some food proteomes relevant to human nutrition. Stable isotope label‐free (SIF) techniques are suitable for comparing an unlimited number of samples by the use of relatively simple experimental workflows. We have developed an internal standard label‐free method based on the intensities of peptide precursor ions from MS/MS spectra, collected in data dependent runs, for the simultaneous qualitative characterization and relative quantification of storage proteins of Lupinus albus seeds in protein extracts of four lupin cultivars (cv Adam, Arés, Lucky, Multitalia). The use of an innovative microfluidic system, the HPLC‐Chip, coupled with a classical IT mass spectrometer, has allowed a complete qualitative characterization of all proteins. In particular, the homology search mode has permitted to identify single amino acid substitutions in the sequences of vicilins (β‐conglutin precursor and vicilin‐like protein). The MS/MS sequencing of substituted peptides confirms the high heterogeneity of vicilins according to the peculiar characteristics of the vicilin‐encoding gene family. Two suitable bioinformatics parameters were optimized for the differential analyses of the main bioactive proteins: the “normalized protein average of common reproducible peptides” (N‐ACRP) for γ‐conglutin, which is a homogeneous protein, and the “normalized protein mean peptide spectral intensity” (N‐MEAN) for the highly heterogenous class of the vicilins.

Effect of genotype and environment on fatty acid composition of Lupinus albus L. seed.

Six cultivars of Lupinus albus L. (white lupin) were grown in two subcontinental-climate environments and one Mediterranean-climate environment in Italy, to assess the influence of genotypic (G) and genotype×environment (GE) interaction effects on grain yield and grain content of oil, total saturated fatty acids (FAs), polyunsaturated FAs, monounsaturated FAs, and ω-3/ω-6 FA ratio. The variance of genotypic effects was much larger than the GE interaction variance for all variables, except for grain yield, indicating that oil content and FA composition of different varieties can be assessed reliably in just a few test environments. Gas-chromatographic analyses highlighted that linoleic acid and α-linolenic acid were in the range 1.76-4.76mg/g flour (7.79-15.81% of total FAs) and 1.17-3.14mg/g flour (5.40-10.36% of total FAs), respectively. As a consequence, the analysed lupin seeds exhibited a very favourable ω-3/ω-6 FA ratio, ranging from 0.49 to 0.79.

Biodegradation of Chlorsulfuron and Metsulfuron‐Methyl by Aspergillus niger in Laboratory Conditions

Two sulfonylurea herbicides, chlorsulfuron and metsulfuron‐methyl, were studied under laboratory conditions, in order to elucidate the biodegradation pathway operated by Aspergillus niger, a common soil fungus, which is often involved in the degradation of xenobiotics. HPLC‐UV was used to study the kinetic of degradation, whereas LC‐MS was used to identify the metabolites structure. In order to avoid the chemical degradation induced by a decrease in pH, due to the production of citric acid by the fungus, the experiments were performed in a buffered neutral medium. No significant degradation for both compounds was observed in mineral medium with 0.2% sodium acetate. On the contrary, in a rich medium, after 28 days the degradations, chemical degradation excluded, were about 30% for chlorsulfuron and 33% for metsulfuron‐methyl. The main microbial metabolites were obtained via cleavage of the sulfonylurea bridge. In addition the fungus seems to be able to hydroxylate the aromatic ring of chlorsulfuron. In the case of metsulfuron‐methyl the only detected metabolite was the triazine derivative, while the aromatic portion was completely degraded. Finally, the demethylation of the methoxy group on the triazine ring, previously observed with a Pseudomonas fluorescens strain, was not observed with A. niger.

Nutraceutical approach to moderate cardiometabolic risk: results of a randomized, double-blind and crossover study with Armolipid Plus.

BACKGROUND Primary cardiovascular prevention may be achieved by lifestyle/nutrition improvements and specific drugs, although a relevant role is now emerging for specific functional foods and nutraceuticals. OBJECTIVES The aim of this study was to evaluate the usefulness of a nutraceutical multitarget approach in subjects with moderate cardiovascular risk and to compare it with pravastatin treatment. SUBJECTS Thirty patients with moderate dyslipidemia and metabolic syndrome (according to the Third Report of the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults) were included in an 8-week randomized, double-blind crossover study and took either placebo or a nutraceutical combination that contained red yeast rice extract, berberine, policosanol, astaxanthin, coenzyme Q10, and folic acid (Armolipid Plus). Subsequently, they were subjected to another 8-week treatment with pravastatin 10 mg/d. This dosage was selected on the basis of its expected -20% efficacy in reducing low-density lipoprotein-cholesterol. RESULTS Treatment with Armolipid Plus led to a significant reduction of total cholesterol (-12.8%) and low-density lipoprotein-cholesterol (-21.1%), similar to pravastatin (-16% and -22.6%, respectively), and an increase of high-density lipoprotein-cholesterol (4.8%). Armolipid Plus improved the leptin-to-adiponectin ratio, whereas adiponectin levels were unchanged. CONCLUSIONS These results indicate that this nutraceutical approach shows a lipid-lowering activity comparable to pravastatin treatment. Hence, it may be a safe and useful option, especially in conditions of moderate cardiovascular risk, in which a pharmacologic intervention may not be appropriate.

Lupin Peptides Lower Low-Density Lipoprotein (LDL) Cholesterol through an Up-regulation of the LDL Receptor/Sterol Regulatory Element Binding Protein 2 (SREBP2) Pathway at HepG2 Cell Line

Previous experiments in suitable animal models and in mild hypercholesterolemic individuals have shown that the consumption of lupin proteins may be useful for controlling total and low-density lipoprotein (LDL) cholesterol levels. With the objective of providing evidence that peptides deriving from the hydrolysis of lupin proteins may be responsible of the observed activities and for investigating the mechanism of action, HepG2 cells were treated with lupin peptides obtained by either pepsin (P) or trypsin (T) hydrolysis, and molecular and functional investigations were performed on the LDL receptor/SREBP2 pathway. For the first time, this paper provides experimental evidence that lupin peptides are able to interfere with the HMGCoAR activity, up-regulating the LDL receptor (136 and 84% vs the control for P and T peptides, respectively, at 1 mg/mL) and SREBP2 proteins (148 and 73% vs the control for P and T peptides, respectively, at 1 mg/mL) via the activation of PI3K/Akt/GSK3β pathways and increasing the LDL uptake at HepG2 cell line (40 and 50% vs the control for P and T peptides, respectively, at 1 mg/mL). These results may be useful in explaining the activities observed in vivo in animals and humans treated with lupin protein.

Low molecular weight coloured compounds formed in xylose—lysine model systems☆

Abstract Aqueous solutions of xylose (1 m ) and lysine monohydrochloride (1 m ), initial pH 5.27, were refluxed for 1 h, either by control of the pH at 5 (by the addition of sodium hydroxide solution during heating) or without pH control (final pH 2.83). The ethyl acetate-extractable components were separated from each model system and represented 0.41 and 0.36 ± 0.05% (m/m), respectively, of the initial reactants for the systems heated with and without pH control. Analysis of the ethyl acetate-extractable components by TLC and HPLC (with diode array detection) showed some similarities, but also many differences between the two systems. Two and seven coloured peaks were analysed, respectively, in the systems heated with and without pH control, but only one was detected in both systems. A novel coloured Maillard reaction product (detected only in the model system heated without pH control) was isolated and purified by repeated semi-preparative TLC and HPLC, prior to analysis by electronic absorption and NMR spectroscopy and by low and high resolution FAB MS.