Use of ORAC to assess antioxidant capacity of human milk

The Antioxidant Capacity of Breast Milk and Plasma of Women with or without Gestational Diabetes Mellitus

Women with gestational diabetes (GD) have reduced antioxidant capacity; however, the relationship between maternal diet, maternal biochemical capacity, breast milk concentration, and infant intake has not been adequately explored in the literature. An exploration of underlying mechanism(s) is warranted, particularly for nutrient antioxidants impacted by maternal intake. These nutrients may provide a means for modifying maternal and infant antioxidant capacity. Oxygen radical absorbance capacity (ORAC), alpha-tocopherol, ascorbic acid, and beta-carotene concentrations were measured in breast milk of women with and without GD. Plasma, three-day diet records, and breast milk were collected at 6 to 8 weeks postpartum. Student’s t-test was used to compare breast milk ORAC, nutrient antioxidant concentration and plasma ORAC between women with and without GD. Pearson correlations were used to determine associations among antioxidant concentrations in breast milk and dietary antioxidant intake. Breast milk antioxidant concentrations were associated with maternal intake of beta-carotene (r = 0.629, p = 0.005). Breast milk and plasma ORAC and antioxidant vitamin concentrations were not significantly different between GD and NG women. Breast milk ORAC associated with breast milk alpha-tocopherol for NG (r = 0.763, p = 0.010), but not GD women (r = 0.385, p = 0.35), and with breast milk ascorbic acid for GD (r = 0.722, p = 0.043) but not NG women (r = 0.141, p = 0.70; interaction p = 0.041). In GD participants, breast milk ORAC was significantly associated with plasma ORAC (r = 0.780, p = 0.039). ORAC and antioxidant vitamin concentrations in breast milk in women with GD were comparable to women with NG; however, the relationships between breast milk ORAC and vitamin concentrations differed in GD versus NG women for alpha-tocopherol and ascorbic acid.

Evaluation of phytochemicals and antioxidant potential of a new polyherbal formulation TC-16: additive, synergistic or antagonistic?

BACKGROUND

Scientific literature has demonstrated the association of free radicals in the aetiology of various chronic diseases. Hence, the identification of potent antioxidants remains a useful task. The combination of multiple herbs in polyherbal formulations (PHF) is often associated with greater therapeutic efficacy due to synergistic interactions. However, antagonism can occur in natural product mixtures and the resultant antioxidant potential might not always be the additive value of the antioxidant properties of each component. In this study, we aimed to evaluate the phytochemicals, antioxidative potential and interaction among the herbs in TC-16, a new PHF comprising Curcuma longa L., Zingiber officinale var. Bentong, Piper nigrum L., Citrofortunella microcarpa (Bunge) Wijnands and Apis dorsata honey.

METHODS

TC-16 was screened for phytochemicals. Phenolic and flavonoid contents of TC-16 and its individual ingredients were determined, followed by assessment of antioxidant properties using in vitro assays including 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonate) (ABTS), 2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC) and β-carotene bleaching (BCB) assays. Interactions among the herbs were also investigated by calculating the difference in antioxidant activity and combination index.

RESULTS

Alkaloids, flavonoids, terpenoids, saponins and glycosides were present in TC-16. TC-16 possessed the highest phenolic (46.14 ± 1.40 mg GAE/g) and flavonoid (132.69 ± 1.43 mg CE/g) contents following C. longa. Synergistic antioxidant activity among the herbs was evident in ORAC and BCB assays which uses mainly hydrogen atom transfer-based antioxidant mechanisms.

CONCLUSIONS

TC-16 demonstrated roles in combating free radicals. In a PHF, synergistic interaction among the herbs is observed in some but not all mechanisms. Mechanisms showing synergistic interactions should be highlighted to maximise the beneficial property of the PHF.

Phytochemical analysis of aerial part of Ikonnikovia kaufmanniana and their protection of DNA damage

Ikonnikovia kaufmanniana is an endemic plant of Kazakhstan of which phytochemical analysis has not been reported. The present study found out that this species enriched with antioxidant chemicals. Isolation and structural identification processes reveal twelve phenolic compounds (1-12) having dihydroflavanonol, flavonol, isoflavone and flavanol skeletons. The annotation of individual components in the extract was carried out by LC-ESI-MS/MS to represent a chemotaxonomic marker of the target plant. The antioxidant activities of all compounds were screened using three different radical sources (DPPH, ORAC, and hydroxyl radicals). Most compounds (1-11) had significant antioxidant activity against three radical sources, and their efficacies were found to differ by their functionality and skeleton. The potential of the isolated compounds in preventing oxidative damage of DNA was evaluated with pBR322 plasmid DNA. Compounds (1, 5, 7, and 8) had protective effects on DNA damaged with 80% efficacy at 60 μM concentration.

Adherence to the Traditional Mediterranean Diet and Human Milk Composition: Rationale, Design, and Subject Characteristics of the MEDIDIET Study

Introduction: Knowledge about how a lactating woman's diet influences the composition of her breast milk is still very limited. In particular, no study has evaluated the role of adherence to the Mediterranean diet on human milk characteristics. Aim: We carried out an observational study to investigate the influence of mother adherence to a Mediterranean diet on her breast milk composition. Methods: Between 2012 and 2014, 300 healthy mothers, who exclusively breastfed their babies, were enrolled from five centers across Italy. During a visit to the hospital center 6 weeks after childbirth these women were asked to provide a sample of their freshly expressed breast milk and to answer a series of questions on personal characteristics and lifestyle factors. The application of a validated food frequency questionnaire allowed the collection of detailed dietary habits. Milk was collected and then stored until chemical analyses were performed. The study has been registered (Trial Registration: Dutch Trial register NTR3468). Descriptive analyses on baseline characteristics of mothers and babies were carried out on the participants, overall and stratified by center. Results: The participants had a mean age of 33 years (SD = 4.06), and a pre-pregnancy BMI of 22.3 Kg/m² (SD = 3.22). Forty-seven percent gave birth to their first child, 40% to the second 13% to the third or subsequent child. Babies had a mean birth weight of 3,324 g (DS = 389), and a mean length of 51 cm (SD = 1.94). Fifty-three percent were males. Conclusion: The present work provides the general description and the characteristics of mothers and babies included in the MediDiet study.

Aqueous root extract of Asparagus cochinchinensis (Lour.) Merr. Has antioxidant activity in D-galactose-induced aging mice

Background

Extracts of plants have been considered as sources of natural antioxidant agents. In this study, we aimed to explore the antioxidant capacity of the aqueous root extract of Asparagus cochinchinensis (Lour.) Merr.

Methods

Using vitamin C (Vc) as a positive control, we analyzed the aqueous root extract of A. cochinchinensis free radical scavenging ability in vitro. We also established a mouse aging model using D-galactose and then treated it with aqueous root extract or Vc. The blood cell count and superoxide dismutase (SOD), catalase (CAT), and nitric oxide synthase (NOS) activities as well as malondialdehyde (MDA) and nitric oxide (NO) contents were measured; pathological examination of tissues was performed; and SOD, glutathione peroxidase (GPX), and NOS expression levels in the serum, liver, and brain tissues were investigated.

Results

In vitro, compared with the antioxidant Vc, the aqueous root extract showed similar 1,1-Diphenyl-2-picrylhydrazyl radical and 3-ethylbenzothiazoline-6-sulfonic·scavenging activities and even significantly increased superoxide anion (p < 0.05) and hydroxyl radical (OH) (p < 0.01) scavenging activities. The aqueous extract significantly increased the white blood cell count as well as enhanced SOD, CAT, and NOS activities (p < 0.01) in aging mice. In addition, the aqueous extract increased the NO content (p < 0.05) and reduced the MDA content (p < 0.05).

Conclusions

The aqueous root extract of A. cochinchinensis showed as strong antioxidant ability as Vc and might prevent aging by reducing radicals.

Different tocopherol isoforms vary in capacity to scavenge free radicals, prevent inflammatory response, and induce apoptosis in both adult- and fetal-derived intestinal epithelial cells

Gamma-tocopherol (γ-Toc) and δ-Toc are two vitamin E isoforms for which biological activities are not well established, yet these isoforms are present in many different sources of vegetable oils and, therefore, contribute significantly to the total dietary intake of vitamin E. Infant formula also contains relatively high amounts of γ-Toc and δ-Toc, compared with that found in human milk. The efficacy of γ-Toc and δ-Toc to modulate cellular events that include oxidative stress, inflammatory response, and apoptosis-mediated cytotoxicity, relative to α-Toc, was determined using differentiated Caco-2 and primary FHs 74 Int cells intestinal epithelial cell lines. Antioxidant capacity of Toc-isoforms followed the order of δ-Toc > γ-Toc > α-Toc against peroxyl radical-induced membrane oxidation in both Caco-2 and FHs 74 Int cells, respectively. The different Toc-isoforms suppressed inflammatory response in interferon (IFN) γ/phorbol myristate acetate (PMA)-induced Caco-2 adult-derived intestinal epithelial cells, but exacerbated both IL8 and PGE2 secretion in fetal-derived FHs 74 Int intestinal epithelial cells. Lastly, Toc exhibited an isoform-dependent apoptosis-mediated cytotoxicity, whereby δ-Toc elicited the greatest apoptosis followed by γ-Toc, whereas α-Toc was not cytotoxic. Cellular uptake of non-α-Toc isoforms were greater (P < 0.05) than that observed for α-Toc in both intestinal epithelial cell lines which in part explains the superior bioactive function observed for both γ-Toc and δ-Toc, compared with α-Toc. We conclude that the non-α-Toc isoforms of vitamin E have distinct roles that influence oxidative stress and inflammatory responses in both adult and fetal-derived intestinal epithelial cell lines.

Simple and fast PO-CL method for the evaluation of antioxidant capacity of hydrophilic and hydrophobic antioxidants

A simple and fast procedure is described for evaluating the antioxidant activity of hydrophilic and hydrophobic compounds by using the peroxyoxalate-chemiluminescence (PO-CL) reaction of Bis(2,4,6-trichlorophenyl) oxalate (TCPO) with hydrogen peroxide in the presence of di(tert-butyl)2-(tert-butylamino)-5-[(E)-2-phenyl-1-ethenyl]3,4-furandicarboxylate as a highly fluorescent fluorophore. The IC50 values of the well-known antioxidants were calculated and the results were expressed as gallic equivalent antioxidant capacity (GEAC). It was found that the proposed method is free of physical quenching and oxidant interference, for this reason, proposed method is able to determine the accurate scavenging activity of the antioxidants to the free radicals. Finally, the proposed method was applied to the evaluation of antioxidant activity of complex real samples such as soybean oil and sunflower oil (as hydrophobic samples) and honey (as hydrophilic sample). To the best of our knowledge, this is the first time that total antioxidant activity can be determined directly in soybean oil, sunflower oil and honey (not in their extracts) using PO-CL reactions.

Quantification of hexanal as an index of lipid oxidation in human milk and association with antioxidant components

Hexanal, a secondary product of lipid oxidation, was identified as the major volatile aldehyde generated from lipid peroxidation in human milk. Hexanal was quantified in human milk using solid phase microextraction-gas chromatography/flame ionization detection that required correction for recovery based on the fat content of human milk. Alpha-tocopherol was the only tocopherol isomer in human milk found to be significantly correlated with hexanal (R = -0.374, p<0.05) and the total antioxidant capacity of human milk (ORAC(Fl) (R = 0.408, p<0.01)). Ascorbic acid content was negatively correlated (R = -0.403, p<0.05) with hexanal, but not to ORAC(Fl) in human milk. The effect of Holder pasteurization on oxidative status of human milk was determined using multiple parameters that included, hexanal level and malondialdehyde as markers of lipid oxidation, vitamins C and E content and antioxidant capacity (e.g. ORAC(Fl)). Pasteurization did not affect the oxidative status of milk as measured by hexanal level, ORAC(Fl) and malondialdehyde content. We conclude that hexanal is a sensitive and useful chemical indicator for assessing peroxidation reactions in human milk and that alpha tocopherol and ascorbic acid are two key antioxidant components in milk that contribute to protection against oxidation of milk lipids.

Tryptophan from human milk induces oxidative stress and upregulates the Nrf-2-mediated stress response in human intestinal cell lines

Chemical screening of digested human milk protein using the oxygen radical absorbance capacity (ORAC(FL)) antioxidant assay confirmed the presence of a peptide fraction (PF23) with high antioxidant activity [5.53 mmol Trolox equivalents (TE)/g] that contained tryptophan as a main component. We evaluated the effects of both PF23 and tryptophan alone on the modulation of oxidative stress in cultured intestinal cells using a dichlorofluorescein diacetate probe. Despite the high ORAC(FL) value, PF23 enhanced (P < 0.05) 2, 2'-azobis (2-amidinopropane) dihydrochloride (peroxyl radical generator)-induced intracellular oxidation in the Caco-2 human adenocarcinoma cell line, suggesting prooxidant activity. Compared to selected peptide fractions with relatively lower ORAC(FL) values, PF23 induced oxidative stress more than all other peptide fractions tested (P < 0.05) and contained more tryptophan than the others (P < 0.05). Similar prooxidant activity was observed for tryptophan when it was added to culture medium for both the Caco-2 cells and FHs 74 Int primary fetal enterocytes, while also exhibiting a high ORAC(FL) value (9.69 mmol TE/g). The effect of tryptophan that involves activation of the Nrf-2 pathway and transcription of antioxidant enzymes was therefore investigated in FHs 74 Int cells. Exposure of infant intestinal cells to tryptophan resulted in Nrf-2 activation and an increase in the gene transcript level of glutathione peroxidase 2. We conclude that tryptophan-induced oxidative stress associated with tryptophan-containing milk peptides induces an adaptive response that involves the activation of the antioxidant responsive signaling pathway in intestinal cells.

Long-wavelength fluorimetric determination of food antioxidant capacity using Nile blue as reagent

A method for the determination of the antioxidant capacity using long-wavelength fluorescence measurements is described for the first time. This method is a modification of the conventional oxygen radical absorbance capacity (ORAC) method that uses fluorescein or phycoerythrin and the generator of peroxyl radicals, 2,2'-azo-bis-(2-methylpropionamidine) dihydrochloride (AAPH). The long-wavelength fluorophor nile blue is proposed as an analytical reagent alternative to these conventional fluorophores. Kinetic curves have been obtained by monitoring the fluorescence variation (λex, 620; λem, 680 nm) with time, using the 96-well microplate format. The vitamin E analogue 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) has been chosen as the model analyte, and the normalized area under the decay curve has been used as the analytical parameter. The dynamic range of the calibration curve is 0.8-8.0 μM, and the detection limit is 0.45 μM. The precision of the method, expressed as relative standard deviation and assayed using 1 and 5 μM Trolox concentrations, was 5.6 and 2.9%, respectively. The method has been applied to the analysis of fruit juices and wines, obtaining results that did not differ significantly from those provided using the ORAC method with fluorescein as reagent.

Antioxidant capacity of human milk and its association with vitamins A and E and fatty acid composition

AIM

The antioxidant capacity of human milk reflects the presence and activity of multiple components, which prevent oxidative rancidity. The aim of this study was to use the Oxygen Radical Absorbance Capacity assay to assess human milk antioxidant capacity and find correlations with milk components.

METHODS

Milk samples collected from 60 breastfeeding women at 1 month postpartum were assayed for antioxidant capacity, vitamins E and A, and fatty acids. Potential statistical relationships of concentrations of vitamins A and E and polyunsaturated fatty acids on the antioxidant capacity of human milk were determined.

RESULTS

Human milk antioxidant capacity was positively attributed to alpha-tocopherol concentration (rho < 0.05). The vitamin A concentration did not significantly contribute to milk antioxidant capacity, but was correlated to milk alpha-tocopherol concentration (r = 0.587; rho < 0.001). There was no evidence of an inverse relationship between polyunsaturated fatty acids concentration and the antioxidant capacity value of milk.

CONCLUSION

This study shows that alpha-tocopherol is an important contributor to the oxidative stability of human milk. Moreover, there was no evidence obtained to show that women who have high levels of milk polyunsaturated fatty acids are predisposed to lower milk antioxidant capacity.