Influence of Oxidation and Dialysis of Phlorotannins on Bioactivity and Composition of Ultrasound-Assisted Extracts from Ascophyllum nodosum.

The isolation and chemical characterization of phlorotannins has gained special attention in recent years due to their specific health-promoting benefits. Flow-cell ultrasound-assisted extraction (90 W/cm2 of sonication power, 2 min of retention time and 20 g solvent/g algae of liquid-solid ratio) was carried out by using double-distilled water (WE) and acetone:water mixture (AWE) as extraction solvents. The AWE showed a higher total polyphenols content (TPC), carbohydrates (CHOs) and antioxidant activities than WE. However, when the WE was purified by using Amberlite XAD16 column, the purified WE (PWE) showed similar a TPC, decreased CHOs and increased antioxidant activity compared to WE. The oxidation of the PWE extract was evaluated under natural, forced and severe oxidation condition for 120 h. Only severe oxidation conditions were able to significantly reduce TPC and antioxidant activities. PWE was dialyzed (20, 10, 3.5 and 2 kDa). The main bioactive fraction of phlorotannins was obtained from 10 to 20 kDa. CHOs were distributed in fractions below 20 kDa. MALDI-TOF analysis was performed for PWE, PD20 and PD2 extracts to analyze the degree of polymerization of phlorotannins, which ranged from 4 to 17 phloroglucinol units/molecule. Fragmentation patterns allowed the proximate identification of several phlorotannins in Ascophyllum nodosum extracts.

In vitro inhibition of starch digestive enzymes by ultrasound-assisted extracted polyphenols from Ascophyllum nodosum seaweeds.

Seaweeds are gaining importance due to their antidiabetic characteristics. This study investigated the inhibitory effects of aqueous Ascophyllum nodosum extracts, obtained by ultrasound-assisted extraction with different sonication powers (70-90 W/cm2 ) and subjected to resin purification, against α-amylase and α-glucosidase enzymes. Different inhibition methodologies were carried out, preincubating the extract either with the enzyme or the substrate. Chemical characterization, in terms of proximate analysis, antioxidant capacity (2,2-diphenyl-1-picryl-hydrazyl-hydrate [DPPH] and FRAP), and polyphenols characteristics (reversed-phase high-performance liquid chromatography [RP-HPLC] and 1 H-NMR) were carried out to explain inhibitory activities of extracts. Sonication power did not influence the proximal composition nor antiradical activity of extracts, but increasing sonication power increased inhibition capacity (>15%) against both starch digestive enzymes. The extract purification largely improved the inhibition efficiency decreasing the IC50 of α-amylase and α-glucosidase by 3.0 and 6.1 times, respectively. Seaweed extracts showed greater inhibition effect when they were preincubated with the enzyme instead of the substrate. RP-HPLC together with 1 H-NMR spectra allowed relating the presence of uronic acids-polyphenols complexes and quinones in the extracts with the different inhibitory capacities of samples. PRACTICAL APPLICATION: The study confirms that ultrasound-assisted extracts from Ascophyllum nodosum can be used to inhibit digestive enzymes. This opens the alternative to be used in foods for modulating glycemic index.

Analgesic and antiinflammatory effects of Nigella orientalis L. seeds fixed oil: Pharmacological potentials and molecular mechanisms.

Nigella species have been widely used in traditional medicine. The aim of this study was to evaluate the antiinflammatory and analgesic potentials of Nigella orientalis L. seeds fixed oil (NOO). The acetic acid writhing test and the formaldehyde-induced licking paw were performed to assess the analgesic activity of the oil. The antiinflammatory activity was first evaluated in vitro by the erythrocyte membrane stabilization then in vivo by xylene- and carrageenan-induced ear and paw edema, respectively. To further understand the molecular mechanism of action of the Nigella extract, lipopolysaccharide-activated RAW 264.7 macrophages were used. Nitric oxide (NO) production was measured by Griess reaction and cell viability by MTT assay. The gene and protein expression of inflammatory mediators were assessed by RT-PCR and western blot, respectively. NOO exerted a potent analgesic effect in in vivo models of writhing test and induced edema. The analyzed molecular mechanisms revealed a role for NO and prostaglandins as molecules mediating the pharmacological effects of the extract through a mechanism involving nuclear factor-κB and mitogen-activated protein kinases. This study demonstrates, for the first time, that the fixed oil of N. orientalis has strong antinociceptive and antiinflammatory properties and might be a promising agent for the treatment of certain inflammation-related diseases.

Influence of natural extracts on the shelf life of modified atmosphere-packaged pork patties.

In this study four natural extracts from tea (TEA), grape (GRA), chestnut (CHE) and seaweed (SEA) with potential antioxidant activity were evaluated in pork patties. During 20 days of storage in modified atmosphere packs at 2°C, pH, colour, lipid oxidation and microbial spoilage parameters of raw minced porcine patties were examined and compared with a synthetic antioxidant (BHT) and control (CON) batch. Due to their higher polyphenol content, GRA and TEA extracts were the most effective antioxidants against lipid oxidation, also limiting colour deterioration. In addition, both natural extracts led to a decrease of total viable counts (TVC), lactic acid bacteria (LAB), Pseudomonas and psychotropic aerobic bacteria compared to the control. Among the four natural compounds tested, tea and grape extracts showed the most potential as alternatives to commercial antioxidants, for increasing the quality and extending the shelf-life of porcine patties.

Recovery and concentration of antioxidants from winery wastes.

Grape and wine byproducts have been extensively studied for the recovery of phenolic compounds with antioxidant activity and a variety of biological actions. The selective recovery and concentration of the phenolic compounds from the liquid phase separated from further diluted winery wastes has been proposed. Adsorption onto non ionic polymeric resins and further desorption with ethanolic solutions was studied. Several commercial food grade resins were screened with the aim of selecting the most suited for the practical recovery of phenolic compounds with radical scavenging activity. Under the optimized desorption conditions (using Sepabeads SP207 or Diaion HP20 as adsorbents and eluting with 96% ethanol at 50 °C) a powdered yellow-light brown product with 50% phenolic content, expressed as gallic acid equivalents, was obtained. The radical scavenging capacity of one gram of product was equivalent to 2-3 g of Trolox.

Effects of calf diet, antioxidants, packaging type and storage time on beef steak storage.

The effect of basal dietary supplemented with vegetable oils plus vitamin E (sunflower, soybean, linseed and a basal diet control), type of packaging (MAP or vacuum), addition of natural antioxidant (grape seed, rosemary) and storage time (0, 7, 14 and 21 days) on lipid oxidation, color stability, vitamin E content, and total aerobic bacterial counts in steaks of Longissimus thoracis was studied. The triple interaction diet × time × packaging affected oxidative stability, redness and yellowness of the meat. TBARS values did not increase with time in vacuum-packaged samples for all dietary treatments. However, samples from MAP and control showed the highest TBARS values after 21 days of storage (0.72 mg MDA/kg of meat, P<0.05). Both exogenous antioxidant extracts and MAP maintained low total aerobic counts in steaks until the 21st day. Calves should be fed a diet supplemented with L-VE, stored in MAP and treated with grape seed extract to extend the shelf life of their meat.

Extracts of Maqui ( Aristotelia chilensis ) and Murta ( Ugni molinae Turcz.): sources of antioxidant compounds and α-Glucosidase/α-Amylase inhibitors.

The objective of this work was to evaluate the antioxidant and antihemolytic activities of crude, aqueous, and organic-aqueous extracts of maqui ( Aristotelia chilensis ) and murta ( Ugni molinae Turcz.), together with their inhibiting effect on enzymes involved in the metabolism of carbohydrates. Radical scavenging activity, inhibition of linoleic acid oxidation in a micellar system, antihemolytic activity, and inhibition of α-amylases and α-glucosidases were analyzed. Crude extracts of maqui leaves and fruits were found to be important sources of polyphenolic compounds, showing 69.0 ± 0.9 and 45.7 ± 1.1 mg GAE/g dm, respectively. Polyphenols from maqui leaves were active as antioxidants and antihemolytic compounds (p < 0.05), showing a noncompetitive inhibiting effect on α-glucosidase. Flavan-3-ol polymers and glycosylated flavonols, such as quercetin glucoside and kaempferol glucoside, were tentatively identified in extracts. This preliminary observation provides the basis for further examination of the suitability of polyphenol-enriched extracts from maqui and murta as nutritional or medicinal supplements with potential human health benefits.

Antiradical activity, phenolics profile, and hydroxymethylfurfural in espresso coffee: influence of technological factors.

The influence of technological factors (decaffeination, brew volume, coffee species, and roast degree) on antiradical activity and phenolics content of espresso coffee is described. The screenings of phenolics profile and other compounds (caffeine and trigonelline), as well as the quantification of hydroxymethylfurfural, were performed by LC-DAD-ESI-MS. Significantly lower (p < 0.05) scavenging activities and phenolics contents were found in decaffeinated espressos when compared with regular ones (32 vs 38% and 324 vs 410 mg/30 mL cup, respectively). A long espresso (70 mL) offers more than twice the phenolics amount of a short one (20 mL). Robusta brews showed higher (p < 0.05) antiradical activity and phenolic contents than arabica ones, for all roast degrees (light, medium, and dark). No significant differences (p > 0.05) were observed for scavenging activities of differently roasted robusta brews, whereas an increase in medium-dark brews was observed for arabica samples. Total phenolics in robusta espressos decreased (p < 0.05) with the increase of roast degree, but no significant differences (p > 0.05) were found between arabica espressos from different roasts. By LC-DAD-ESI-MS, 23 hydroxycinnamic derivatives were found, including chlorogenic acids, lactones, and cinnamoyl-amino acid conjugates. The amount of each compound was differently affected by species and roast. Robusta brews presented superior levels of caffeine and chlorogenic acids, whereas arabica ones contained more trigonelline. Hydroxymethylfurfural contents in the brew (30 mL) varied from 2.60 to 0.84 mg for light- and dark-roasted arabicas and from 1.29 to 0.68 mg for light- and dark-roasted robustas, respectively.

Identification of polymeric procyanidins from pine bark by mass spectrometry.

Pine bark is an important source of polyphenolic compounds, mainly procyanidins, with reported protective effects against disease. In previous works, barks of two varieties of pine (P. pinaster and P. radiata) were extracted with ethanol, and partially purified to obtain the aqueous fractions (FA), that contained mainly polymeric procyanidins. The mean degree of polymerization was 7.9 for radiata (rFA) and 10.6 for pinaster (pFA). FAs were chromatographed on Sephadex LH-20 by using a gradient of methanol, water and acetone, to render a series of sub-fractions. In this work, the procyanidin compositions of these sub-fractions were analyzed using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS). The mass spectra of sub-fractions from FA of P. pinaster showed signals of procyanidin polymers up to tridecamers, whereas for those from P. radiata the maximum degree of polymerization was 15. For this latter case, the MALDI-TOF mass spectra detected the presence of prodelphinidins in a small amount.

Processing of Rosa rubiginosa: extraction of oil and antioxidant substances.

In this work, a study about the effect of various operational conditions on the quantity of oil and soluble solids capable of being extracted from rosa mosqueta rosehip seeds is undertaken. Both the particle sizes assayed (0.6mm, 0.6-1mm, and 1-2mm) and the solvent-to-solid ratios (15:1, 25:1, and 50:1) showed a remarkable influence on the extraction efficiency. Extracted substances obtained by using the minor particle size or the maximum solvent-to-solid ratio doubled, at least, those attained by working under any other conditions. A major weight of kinetics upon equilibrium factors can be inferred from the short extraction times and high effective diffusivity values (being the lower one 1.97x10(-11)m(2)s(-1)) assessed for any condition. The antioxidant power of extracts was evaluated by ability to scavenge the DPPH radical. Results noteworthy depended on the solvent used to extract; whilst an approximately 80% DPPH inhibition percentage was reached in ethanol extracts, values of 52.2% or 41% were found in methanol and aqueous extracts, respectively. Even so, antioxidant capacity of Rosa rubiginosa extracts was much higher than that reported for other agricultural matrixes.

Effect of solvent, temperature, and solvent-to-solid ratio on the total phenolic content and antiradical activity of extracts from different components of grape pomace.

Grape byproducts were subjected to an extraction process under various different experimental conditions (namely, solvent type, temperature, solvent-to-solid ratio, time contact, and raw material) in order to study the effect of these conditions on the yield of phenolic compounds and the corresponding antiradical activity of extracts. Although the order of decreasing capacity to extract soluble materials was ethanol > methanol > water, methanol was the most selective for extracting phenolic compounds. Temperature and solvent-to-solid ratio were found to have a critical role in extraction efficiency; values of 50 degrees C (between 25 and 50 degrees C) and 1:1 (between 1:1 and 5:1) maximized the antiradical activity of phenolic extracts. In addition, extracts from grape samples previously subjected to distillation reached higher antiradical values in comparison to those coming directly from pressing; in both cases, seed extracts showed better results than those of stem when ethanol or water was employed, whereas the opposite occurred in the case of methanol. These differences were attributed to the different phenolic compositions of the considered fractions.