General method for extraction of blueberry anthocyanins and identification using high performance liquid chromatography-electrospray ionization-ion trap-time of flight-mass spectrometry

Influence of Extraction Conditions on Ultrasound-Assisted Recovery of Bioactive Phenolics from Blueberry Pomace and Their Antioxidant Activity

The increase in diet-related chronic diseases has prompted the search for health-promoting compounds and methods to ensure their quality. Blueberry pomace is a rich yet underutilized source of bioactive polyphenols. For these high-value bioactive molecules, ultrasound-assisted extraction (USAE) is an attractive and green alternative to conventional extraction techniques for improving purity and yields. This study aimed to assess the impact of USAE parameters (sonication time, solvent composition, solid/liquid ratio, pH and temperature) on the recovery of phenolic compounds from blueberry pomace and antioxidant activity of the extracts. Total phenolic, flavonoid and anthocyanin contents (TPC, TFC and TAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging activity were analysed. USAE in 50% ethanol/water was the most efficient, yielding the highest TPC (22.33 mg/g dry matter (DM)), TFC (19.41 mg/g DM), TAC (31.32 mg/g DM) and DPPH radical scavenging activity (41.79 mg Trolox/g DM). USAE in water showed the lowest values even at low (1/40) solid/liquid ratio (7.85 mg/g DM, 3.49 mg/g DM, and 18.96 mg/g DM for TPC, TFC and TAC, respectively). Decreasing the solid/liquid ratio in water or 50% ethanol significantly increased TPC, TFC, TAC and DPPH radical scavenging. With ethanol, increasing the temperature in the range 20–40 °C decreased TPC but increased TFC and DPPH radical scavenging activity. Anthocyanin profiles of water and ethanolic extracts were qualitatively similar, consisting of malvidin, delphinidin, petunidin and cyanidin. These findings indicate that USAE is a method of choice for extracting high-value bioactive phenolics from blueberry pomace. Selective enrichment of different phenolic fractions is possible under select extraction conditions.

Lipidomics study of the protective effects of isosteviol sodium on stroke rats using ultra high-performance supercritical fluid chromatography coupling with ion-trap and time-of-flight tandem mass spectrometry

Isosteviol sodium (STV-Na) was reported to possess significant protective effects on ischemic stroke in recent years. However, the protective mechanism of STV-Na against stroke was still unclear. In this work, an untargeted lipidomics approach based on the ultra high-performance supercritical fluid chromatography coupling with ion-trap and time-of-flight tandem mass spectrometry (UHSFC-IT-TOF/MS) was employed to investigate the lipid profiles of stroke rats with STV-Na treatment for the first time. The possible mechanism of STV-Na was further elucidated. The UHSFC-IT-TOF/MS-based method achieved a fast separation of various lipids within 9 min with a qualified repeatability. Multivariate statistical analysis was used to show differences in lipid profiles induced by stroke and STV-Na treatment. The results showed a clear separation of the model group and the sham group, with the STV-Na group as well as EDA group located much closer to the sham group than the model group, which was consistent with the results of physiological and pathological assays, indicating the protective effects of STV-Na. Fifteen differential lipids that presented significant differences between the sham group and the model group were screened and identified. With the treatment of STV-Na, 15 differential lipids in stroke rats showed a tendency to the normal levels. Among them, 6 lipids were significantly reversed to the normal levels by STV-Na. The results of pathway analysis suggested the protective effects of STV-Na might be related to the regulation of several metabolic pathways including glycerophospholipid metabolism, arachidonic acid metabolism and sphingolipid metabolism. This work demonstrated that the UHSFC-IT-TOF/MS-based lipidomics profiling method was a useful tool to investigate the protective effects of STV-Na against stroke.

Mineral Composition of Wild and Cultivated Blueberries

The concentrations of 13 elements (Al, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, and Zn) were determined in several samples of native (wild) naturally growing and cultivated blueberry fruits. The total metal contents after mineralization were analyzed by inductively coupled plasma optical emission spectrometry. Reliability of the procedure was checked by the analysis of the certified reference materials Mixed Polish Herbs (INGT-MPH-2) and Leaves of Poplar (NCS DC 73350). In the fruits collected in the forest (wild blueberries), higher contents of Ca, Na, and Mg as well as Mn and Zn were observed. Similar levels of Cu, Cr, Fe, and Ni were detected in both wild-growing and cultivated plants. The significantly higher content of Fe and Cd in cultivated blueberries was connected with the content of these metals in soil samples collected from the same places. The metal extraction efficiency by hot water varied widely for the different blueberries (wild or cultivated) as well as their form (fresh or dried).

Optimized preparation of anthocyanin-rich extract from black rice and its effects on in vitro digestibility

The procedure for obtaining anthocyanin-enriched extracts from black rice was optimized by response surface methodology, and the effects of the optimized extract on in vitro starch digestibility were investigated in a wheat flour gel model. The experimental results were well-described by a polynomial multiple regression model (R² = 0.8812, p = 0.0546) with regard to anthocyanin content in anthocyanin-enriched extracts from black rice. The optimal conditions for obtaining anthocyanin-enriched extracts from black rice were 50.78% ethanol and 1 N HCl (0.60 mL), yielding a predicted anthocyanin content of 624.27 mg cyanidin 3 glucoside extract. The optimized anthocyanin-enriched extract was a stronger inhibitor of α-glucosidase than acarbose. Furthermore, the predicted glycemic index values of gels prepared with the optimized extract were significantly lower than that of wheat flour gel. These results indicate that the optimized extract suppressed starch hydrolysis by inhibiting digestive enzymes.

Identification of Anthocyanins from Four Kinds of Berries and Their Inhibition Activity to α-Glycosidase and Protein Tyrosine Phosphatase 1B by HPLC-FT-ICR MS/MS

The polyphenolic profiles of four berries (blueberry, bilberry, mulberry, and cranberry) in China were investigated using Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS). Thirty-nine polyphenols including 26 anthocyanins, 9 flavonoids, and 4 phenolic acids were identified accurately. Cyanidin aglycones are common in four berries, and malvidin aglycones are the main compounds found in bilberry and cranberry. The anthocyanin level in blueberry are the highest with 739.6 ± 17.14 mg/g DW and presented the strongest antioxidant capacity in DPPH, ABTS, FRAP, and ORAC assay. In α-glycosidase, the inhibition activity was in the following order: mulberry > bilberry > blueberry > cranberry. For the PTP1B inhibition assay, blueberry demonstrated the highest inhibitory effect with IC₅₀ 3.06 ± 0.02 μg/mL, followed by bilberry, mulberry, and cranberry. Molecular docking results showed that cyanidin aglycones had the highest inhibition activity to PTP1B.

Antiproliferative and proapoptotic activities of anthocyanin and anthocyanidin extracts from blueberry fruits on B16-F10 melanoma cells

Background: Anthocyanins have been proven to affect multiple cancer-associated processes in different cancer cell lines. However, relatively few studies have investigated the effects of blueberry anthocyanins on metastatic melanoma. Thus, this study focuses on evaluating the chemopreventive potential of blueberry anthocyanins and their aglycones (anthocyanidins) in B16-F10 melanoma cells. Methods: Blueberry anthocyanin and anthocyanidin extracts were prepared mainly by combined chromatography techniques. Their antiproliferative and proapoptotic effects on B16-F10 cells were evaluated by MTT assay, calcein acetoxymethyl ester/propidium iodide (calcein-AM/PI) staining, and flow cytometry of the cell cycle and apoptosis. Results: The MTT and calcein-AM/PI staining results showed that both anthocyanin (purity of 62.5%) and anthocyanidin (75.1%) extracts could significantly inhibit the viability and proliferation of B16-F10 cells in a dose-dependent manner, while anthocyanidin extracts exhibited significantly higher (p < 0.05) cytotoxicity than anthocyanin extracts. Furthermore, anthocyanin and anthocyanidin extracts blocked cell cycle procession at the G0/G1 phase below 400 and 200 μg/mL, and induced early apoptosis below 400 and 300 μg/mL, respectively. Conclusions: These data suggest that both anthocyanin and anthocyanidin extracts inhibit the proliferation and trigger the apoptosis of B16-F10 cells, and anthocyanidin extracts may be a more promising candidate in preventing metastatic melanoma than anthocyanin extracts.

Effect of fermentation and sterilization on anthocyanins in blueberry

BACKGROUND

Blueberry products have various health benefits due to their high content of dietary anthocyanins. The aim of this study was to investigate the impact of fermentation and sterilization on total anthocyanin content, composition and some quality attributes of blueberry puree. The blueberry puree used here was fermented for 40 h at 37 °C by Lactobacillus after sterilization. The method of ultra-performance liquid chromatography-mass spectrometry was optimized for the rapid analysis of anthocyanins. Quality attributes including pH, color, total soluble solids and viscosity were measured.

RESULTS

A total of 21 anthocyanins and five anthocyanidins were quantified by ultra-performance liquid chromatography. Fermented blueberry had reduced total anthocyanin content (29%) and levels of individual anthocyanins compared with fresh blueberry. Total anthocyanin content was decreased 46% by sterilization, and different degradation behavior of individual anthocyanin was appeared between fermented and sterilized-fermented blueberry puree. Fermentation and sterilization decreased the total soluble solids and pH and changed color parameters, while minimally influencing viscosity.

CONCLUSIONS

The loss of total anthocyanin content by fermentation was related to the unstable structure of blueberry anthocyanins. Anthocyanins are sensitive to temperature (>80 °C), and degradation of anthocyanins by sterilization in blueberry should be considered in the fermentation procedure. © 2016 Society of Chemical Industry.

Chitosan-cellulose nanocrystal microencapsulation to improve encapsulation efficiency and stability of entrapped fruit anthocyanins

For improving stability of fruit anthocyanins (ACN), this study investigated the use of cellulose nanocrystal (CNC) as a macroion crosslinking agent to develop blueberry anthocyanin extract (BB)-loaded chitosan (CH)-CNC microcapsules, and compared with CH-sodium tripolyphosphate (TPP) ones. The yield of microcapsules (∼6.9g) and total monomeric anthocyanin recovery (∼94%) were significantly (P<0.05) higher in CH-CNC microcapsules than those (∼0.3g and ∼33%, respectively) in CH-TPP microcapsules. ACN distribution (%) in CH-CNC microcapsules was 61% on the surfaces, 12% bound with the matrix, and 27% in cores, but that in CH-TPP microcapsules was mostly presented on the surfaces (99%). CH-CNC microcapsules were more stable at pH 7.4 buffer by showing less ACN release (%) than that of CH-TPP, but no difference at pH 1.2. CH-CNC and CH-TPP microcapsules showed different structural and morphological properties. This study demonstrated that CNC is a promising crosslinking agent forming stable BB-loaded CH microcapsules.

Extraction optimization and identification of anthocyanins from Nitraria tangutorun Bobr. seed meal and establishment of a green analytical method of anthocyanins

This study aimed to extract and identify anthocyanins from Nitraria tangutorun Bobr. seed meal and establish a green analytical method of anthocyanins. Ultrasound-assisted extraction of anthocyanins from N. tangutorun seed meal was optimized using response surface methodology. Extraction at 70°C for 32.73 min using 51.15% ethanol rendered an extract with 65.04mg/100g of anthocyanins and 947.39mg/100g of polyphenols. An in vitro antioxidant assay showed that the extract exhibited a potent DPPH radical-scavenging capacity. Eight anthocyanins in N. tangutorun seed meal were identified by HPLC-MS, and the main anthocyanin was cyanidin-3-O-(trans-p-coumaroyl)-diglucoside (18.17mg/100g). A green HPLC-DAD method was developed to analyse anthocyanins. A mixtures of ethanol and a 5% (v/v) formic acid aqueous solution at a 20:80 (v/v) ratio was used as the optimized mobile phase. The method was accurate, stable and reliable and could be used to investigate anthocyanins from N. tangutorun seed meal.

Chemical Characterization and Cytotoxic Activity of Blueberry Extracts (cv. Misty) Cultivated in Brazil

Vaccinium corymbosum (L.) varieties cultivation is relatively recent in Brazil, but its production has been intensified given its good adaptability to the Southern Brazil climate. Blueberries are a rich source of phenolic compounds and contain significant levels of anthocyanins, flavonols, chlorogenic acids, and procyanidins, which lead to different biological activities. Chemical identification of skin and whole hydroalcoholic blueberry extracts (ExtSB and ExtWB) revealed the presence of anthocyanins concentrated in the skin and others chemicals compounds as quercetin glycosides, proanthocyanins dimers, citric, and chlorogenic acid in the pulp. Selectivity for tumor cell lines (Hep-2, HeLa, HT-29) using ExtSB and ExtWB extracts was observed through MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay after 24 h of treatment when compared to nontumor cells (MRC-5). Morphological changes and late stages of apoptotic and necrosis process were seen in HT-29 cell line after ExtWB treatment, compared to nontumor cell line MRC-5. These results are in agreement with other studies that indicate the activity of compounds such as anthocyanins and other molecules found in Southern Highbush blueberry variety, attributed to promote beneficial effects on health that may respond as cytotoxic natural agent and contribute to cancer treatment.

Appropriate choice of collision-induced dissociation energy for qualitative analysis of notoginsenosides based on liquid chromatography hybrid ion trap time-of-flight mass spectrometry

Liquid chromatography hybrid ion trap/time-of-flight mass spectrometry possessesd both the MS(n) ability of ion trap and the excellent resolution of a time-of-flight, and has been widely used to identify drug metabolites and determine trace multi-components for in natural products. Collision energy, one of the most important factors in acquiring MS(n) information, could be set freely in the range of 10%-400%. Herein, notoginsenosides were chosen as model compounds to build a novel methodology for the collision energy optimization. Firstly, the fragmental patterns of the representatives for the authentic standards of protopanaxadiol-type and protopanaxatriol-type notoginsenosides authentic standards were obtained based on accurate MS(2) and MS(3) measurements via liquid chromatography hybrid ion trap/time-of-flight mass spectrometry. Then the extracted ion chromatograms of characteristic product ions of notoginsenosides in Panax Notoginseng Extract, which were produced under a series of collision energies and, were compared to screen out the optimum collision energies values for MS(2) and MS(3). The results demonstrated that the qualitative capability of liquid chromatography hybrid ion trap/time-of-flight mass spectrometry was greatly influenced by collision energies, and 50% of MS(2) collision energy was found to produce the highest collision-induced dissociation efficiency for notoginsenosides. BesidesAddtionally, the highest collision-induced dissociation efficiency appeared when the collision energy was set at 75% in the MS(3) stage.

Phenolic Compounds in Chilean Mistletoe (Quintral, Tristerix tetrandus) Analyzed by UHPLC-Q/Orbitrap/MS/MS and Its Antioxidant Properties

Mass spectrometry has become a method of choice to characterize bioactive compounds in biological samples because of its sensitivity and selectivity. Hybrid ultra-HPLC hyphenated with Orbitrap mass analyzer is an innovative state of the art technology that allows fast and accurate metabolomic analyses. In this work the metabolites of a Chilean mistletoe endemic to the VIII region of Chile were investigated for the first time using UHPLC mass analysis (UHPLC-PDA-HESI-Orbitrap MSⁿ). The anthocyanins, together with the non-pigmented phenolics were fingerprinted and correlated with the antioxidant capacities measured by the bleaching of the DPPH radical, the ferric reducing antioxidant power (FRAP), the superoxide anion scavenging activity assay (SA), and total content of phenolics, flavonoids and anthocyanins measured by spectroscopic methods. Six anthocyanins were identified, and among them, the 3-O-glycosides of delphinidin and cyanidin were the major ones. In addition, several phenolic acids (including feruloylquinic acid, feruloyl glucose, chlorogenic acid) and several flavonols (luteolin, quercetin, apigenin, isorhamnetin and glycoside derivatives) were also identified. The mistletoe leaves showed the highest antioxidant activity as measured by the DPPH radical bleaching, ferric reducing antioxidant power and superoxide anion scavenging activity tests (13.38 ± 0.47 µg/mL, 125.32 ± 5.96 µmolTE/g DW and 84.06 ± 4.59 at 100 µg/mL, respectively).

Fast Detection of Phenolic Compounds in Extracts of Easter Pears (Pyrus communis) from the Atacama Desert by Ultrahigh-Performance Liquid Chromatography and Mass Spectrometry (UHPLC-Q/Orbitrap/MS/MS)

A small Chilean variety of pears growing in the town of Toconao, an oasis located at the northeastern edge of the Salar de Atacama, northern Chile, was studied by means of modern PDA and high resolution mass spectral data (UHPLC-PDA-HESI-orbitrap-MS/MS). In addition, the antioxidant features of the fruits were compared with the varieties Packhman’s Triumph and Abate Fetel and correlated with the presence of phenolic compounds. The non-pigmented phenolics were fingerprinted and related to the antioxidant capacities measured by the bleaching of the DPPH radical, the ferric reducing antioxidant power (FRAP), the superoxide anion scavenging activity assay (SA), and total content of phenolics and flavonoids measured by spectroscopic methods. The machine allowed a fast separation of 15 min employing a flow rate of 1 mL per minute and could accurately identify 25 compounds, including several isorhamnetin derivatives and phenolic acids, present in the peel and pulps of this Chilean variety for the first time. The compounds were monitored using a wavelength range of 210–800 nm. The native small Chilean pear showed the highest antioxidant activity measured as the bleaching of the DPPH radical, the ferric reducing antioxidant power and superoxide anion scavenging activity (8.61 ± 0.65 μg/mL, 712.63 ± 12.12 micromols trolox equivalents (μmol/TE)/100 g FW, and 82.89% ± 2.52% at 100 μg/mL, respectively).

Highly efficient extraction of anthocyanins from grape skin using deep eutectic solvents as green and tunable media

Deep eutectic solvents (DESs) were investigated as tunable, environmentally benign, yet superior extraction media to enhance the extraction of anthocyanins from grape skin, which is usually discarded as waste. Ten DESs containing choline chloride as hydrogen bond acceptor combined with different hydrogen bond donors were screened for high extraction efficiencies based on the anthocyanin extraction yields. As a result, citric acid, D-(+)-maltose, and fructose were selected as the effective DES components, and the newly designed DES, CM-6 that is composed of citric acid and D-(+)-maltose at 4:1 molar ratio, exhibited significantly higher levels of anthocyanin extraction yields than conventional extraction solvents such as 80% aqueous methanol. The final extraction method was established based on the ultrasound-assisted extraction under conditions optimized using response surface methodology. Its extraction yields were double or even higher than those of conventional methods that are time-consuming and use volatile organic solvents. Our method is truly a green method for anthocyanin extraction with great extraction efficiency using a minimal amount of time and solvent. Moreover, this study suggested that grape skin, the by-products of grape juice processing, could serve as a valuable source for safe, natural colorants or antioxidants by use of the eco-friendly extraction solvent, CM-6.

Bioactive Compounds and Antioxidant Activity in Different Types of Berries

Berries, especially members of several families, such as Rosaceae (strawberry, raspberry, blackberry), and Ericaceae (blueberry, cranberry), belong to the best dietary sources of bioactive compounds (BAC). They have delicious taste and flavor, have economic importance, and because of the antioxidant properties of BAC, they are of great interest also for nutritionists and food technologists due to the opportunity to use BAC as functional foods ingredients. The bioactive compounds in berries contain mainly phenolic compounds (phenolic acids, flavonoids, such as anthocyanins and flavonols, and tannins) and ascorbic acid. These compounds, either individually or combined, are responsible for various health benefits of berries, such as prevention of inflammation disorders, cardiovascular diseases, or protective effects to lower the risk of various cancers. In this review bioactive compounds of commonly consumed berries are described, as well as the factors influencing their antioxidant capacity and their health benefits.

Adsorption properties of macroporous adsorbent resins for separation of anthocyanins from mulberry

In this study, the adsorption/desorption characteristics of mulberry anthocyanins (MA) on five types of macroporous resins (XAD-7HP, AB-8, HP-20, D-101 and X-5) were evaluated, XAD-7HP and AB-8 showed higher adsorption/desorption capacities. On the basis of static adsorption test, XAD-7HP and AB-8 resins were selected for kinetics, isotherms and thermodynamics. The adsorption mechanism indicated that the process was better explained by pseudo-first-order kinetics and the Langmuir isotherm model, and the thermodynamics tests showed that the processes were exothermic, spontaneous and thermodynamically feasible. Dynamic tests were performed on a column packed with XAD-7HP and AB-8, and breakthrough volume was reached at 15 and 14 bed volumes of MA solution, respectively. The purity of the fraction by 40% ethanol elution on XAD-7HP reached 93.6%, from which cyanidin-3-glucoside and cyanidin-3-rutinoside were identified by HPLC-ESI-MS/MS. The method could be used to prepare high purity anthocyanins from mulberry fruits as well as other plants.

Development and validation of a liquid chromatography method for anthocyanins in strawberry (Fragaria spp.) and complementary studies on stability, kinetics and antioxidant power

A RPLC-DAD method for the analysis of eight anthocyanins was developed, validated and applied to strawberry extracts. The chromatographic method was conducted under gradient elution in acidulated water-methanol mobile phase and octadecyl-silica columns. An ultrasound extraction procedure was optimized by a 3(2) factorial design (%HCl in methanol, temperature, and time) and response surface methodology. Method validation was performed according to the following parameters: linearity (R(2)>0.99, p-value<10(-4), F>725), LOD (3-7 μmol L(-1)) and LOQ (9-22 μmol L(-1)), selectivity/specificity (baseline separation of all analytes and peak purity), instrumental precision (<6.4%CV), repeatability (<6.3%CV) and intermediate precision (<9.9%CV), recovery (83-99%), robustness (mobile phase pH, column temperature and flow rate) and stability (high temperatures and storage; 1st order kinetics). The antioxidant power of anthocyanins was measured on-line (ABTS(+) reaction; Trolox as reference). Ten strawberry extracts were quantified (average values: 24.2 μg/g for cyanidin-3-glucoside and 49.1 μg/g for pelargonidin-3-glucoside).