Betalains and phenolic compounds of leaves and stems of Alternanthera brasiliana and Alternanthera tenella.

Betacyanins and phenolic compounds from acetonitrile:acidified water extracts of Alternanthera brasiliana and Alternanthera tenella were characterized and quantified using a high-performance liquid chromatography system coupled with diode array and electrospray mass spectrometry detection. Four betacyanins (amaranthine, isoamaranthine, betanin and isobetanin) were tentatively identified and quantified. Twenty eight phenolic compounds of four different families (hydroxybenzoic and hydroxycinnamic acids, flavones and flavonols) were separated and characterized on the basis of their accurate MS and MS/MS information out of which ten compounds were confirmed by authentic standards. These plant species could be considered as an especially rich source of natural bioactive compounds and potential food colorants. A. brasiliana showed the highest betacyanin and polyphenols content (89µg/g and 35,243µg/g, respectively). Among polyphenols, flavonols were the more abundant (kaempferol-glucoside, kaempferol-rutinoside and kaempferol-rhamnosyl-rhamnosyl-glycoside). Meanwhile, A. tenella showed a different polyphenols profile with flavones as major compounds (glucopyranosil-vitexin and vitexin). As a novelty, pentosyl-vitexin and pentosyl-isovitexin were detected for the first time in Alternanthera plants. Both A. brasiliana and A. tenella leaves showed high total polyphenol content and in vitro antioxidant activity (FRAP). These results provide an analytical base concerning the phenolic and betalains composition and the antioxidant properties of two members of the promising Alternanthera gender, for subsequent applications, such as functional food ingredients.

Apolipoprotein A-II polymorphism: relationships to behavioural and hormonal mediators of obesity.

BACKGROUND: The interaction between apolipoprotein A-II (APOA2) m265 genotype and saturated fat for obesity traits has been more extensively demonstrated than for any other locus, but behavioural and hormonal mechanisms underlying this relationship are unexplored. In this study, we evaluated relationships between APOA2 and obesity risk with particular focus on patterns of eating and ghrelin, a hormonal regulator of food intake. DESIGN: Cross-sectional study. SUBJECTS: Overweight and obese subjects (n=1225) were evaluated at baseline in five weight loss clinics in southeastern Spain. METHODS: Behavioural data were assessed using a checklist of weight loss obstacles. Logistic regression models were fitted to estimate the risk of a specific behaviour associated with APOA2 genotype. Relationships between APOA2 genotype and saturated fat intakes for anthropometric traits and plasma ghrelin were evaluated by analysis of variance. To construct categorical variables to evaluate interactions, saturated fat intake was dichotomized into high and low according to the population median intake or as tertiles. RESULTS: Homozygous minor (CC) subjects were more likely to exhibit behaviours that impede weight loss ('Do you skip meals', odds ratio (OR)=2.09, P=0.008) and less likely to exhibit the protective behaviour of 'Do you plan meals in advance' (OR=0.64, P=0.034). Plasma ghrelin for CC subjects consuming low saturated fat was lower compared with (1) CC subjects consuming high saturated fat, (2) TT+TC carriers consuming low saturated fat and (3) TT+TC carriers consuming high saturated fat (all P<0.05). CONCLUSIONS: APOA2 m265 genotype may be associated with eating behaviours and dietary modulation of plasma ghrelin. Expansion of knowledge of APOA2 and obesity to include modulation of specific behaviours and hormonal mediators not only broadens understanding of gene-diet interactions, but also facilitates the pragmatic, future goal of developing dietary guidelines based on genotype.

Anthocyanins are absorbed in glycated forms in elderly women: a pharmacokinetic study.

BACKGROUND: Anthocyanins are potent antioxidants that are widely distributed in fruit, vegetables, and red wines. Anthocyanin products are also prescribed as medicines in many countries for treating various diseases. However, the pharmacokinetics of dietary anthocyanins are not known in humans because these glycosides were long considered nonabsorbable. OBJECTIVE: The objective of this study was to determine whether anthocyanins can be absorbed as glycosides and to evaluate their pharmacokinetics in humans. DESIGN: Four healthy elderly women consumed 720 mg anthocyanins. A series of blood and urine samples were collected before and after consumption of the anthocyanins. Anthocyanins were measured in plasma and urine by combining an octadecylsilane solid-phase extraction for sample preparation and an HPLC system with diode array for anthocyanin separation and detection. The structures of anthocyanins as glycosides in plasma and urine were further confirmed by using liquid chromatography-mass spectrometry. RESULTS: Anthocyanins were detected as glycosides in plasma and urine. The maximum plasma concentration of total anthocyanins varied from 55.3 to 168.3 nmol/L, with an average of 97.4 nmol/L, and was reached within 71.3 min. The elimination of plasma anthocyanins appeared to follow first-order kinetics. The elimination half-life of plasma total anthocyanins was calculated to be 132.6 min. Most anthocyanin compounds were excreted in urine during the first 4 h. The excretion rate of total anthocyanins was 77 microg/h during the first 4 h and 13 microg/h during the second 4 h. CONCLUSION: Anthocyanins are absorbed in their unchanged glycated forms in elderly women.

Antioxidant activity of selected Spanish wines in corn oil emulsions.

Wines contain phenolic compounds that may be useful for preventing lipid oxidation as dietary antioxidants. This study was aimed at evaluating the antioxidant activity in corn oil emulsions of seventeen selected Spanish wines and two California wines. The inhibition of hydroperoxide formation at 10 microM gallic acid equivalents (GAE) varied from 8.4% to 40.2% with the red wines, from 20.9% to 45.8% with the rosé wines, and from 6.5% to 47.0% with the white wines. The inhibition of hydroperoxide formation at 20 microM GAE varied from 11.9% to 34.1% with the red wines, from 0.1% to 34. 5% with the rosé wines, and from 3.3% to 37.2% with the white wines. The inhibition of hexanal formation at 10 microM GAE varied from 23. 6% to 64.4% with the red wines, from 42.7% to 68.5% with the rosé wines, and from 28.4% to 68.8% with the white wines. The inhibition of hexanal formation at 20 microM GAE varied from 33.0% to 46.3% with the red wines, from 11.3% to 66.5% with the rosé wines, and from -16.7% to +21.0% with the white wines. The antioxidant effect decreased with increasing concentration. This antioxidant activity was related to the five main groups of phenolic compounds identified in wines by HPLC. The relative antioxidant activity correlated positively with the total phenol content of wines (by the Folin-Ciocalteu method and by HPLC), benzoic acids, anthocyanins, flavan-3-ols, and flavonols, for the inhibition of hydroperoxides and hexanal at 10 and 20 microM GAE.

Free radical scavenging capacity in the aging of selected red Spanish wines.

Free radical scavenging capacity by the DPPH(*) method and main physicochemical properties, polyphenols content by HPLC, color by a tristimulus colorimeter, and UV-vis spectra in the aging of selected red Spanish wines, were studied. As the wines age, they become darker (lower lightness, L) and increase their hue angle (lower red color) as well as the ratio of absorbance at 420 nm to that at 520 nm. Main polyphenolics identified in the samples were tannic acid, oenin, and gallic acid. The antiradical efficiency of the samples increased during aging, which could be related to an increase in the tannic acid concentration shown by the following correlationship: EC(50) = 1/(0.18 + 0.0011[tannic acid](mg/L)) with a correlation coefficient of 0.744.