Important Antioxidant Compounds Research Articles

Ascorbic acid supplementation partially prevents the delayed reproductive development in juvenile male rats exposed to rosuvastatin since prepuberty

Dyslipidemias are occurring earlier in the population due to the increase of obesity and bad eating habits. Rosuvastatin inhibits the enzyme HMG-CoA reductase, decreasing total cholesterol. Ascorbic acid is an important antioxidant compound for male reproductive system. This study aimed to evaluate whether ascorbic acid supplementation may prevent the reproductive damage provoked by rosuvastatin administration at prepuberty. Male pups were distributed into six experimental groups that received saline solution 0.9%, 3 or 10mg/kg/day of rosuvastatin, 150mg/day of ascorbic acid, or 150mg/day of ascorbic acid associated with 3 or 10mg/kg/day of rosuvastatin from post-natal day (PND) 23 until PND53. Rosuvastatin-treated groups showed delayed puberty installation, androgen depletion and impairment on testicular and epididymal morphology. Ascorbic acid partially prevented these reproductive damages. In conclusion, rosuvastatin exposure is a probable risk to reproductive development and ascorbic acid supplementation may be useful to prevent the reproductive impairment of rosuvastatin exposure.

Alpha-lipoic acid attenuates acute neuroinflammation and long-term cognitive impairment after polymicrobial sepsis

Sepsis is a complication of an infection which imbalance the normal regulation of several organ systems, including the central nervous system (CNS). Evidence points towards inflammation and oxidative stress as major steps associated with brain dysfunction in sepsis. Thus, we investigated the α-lipoic acid (ALA) effect as an important antioxidant compound on brain dysfunction in rats. Wistar rats were subjected to sepsis by cecal ligation and perforation (CLP) or sham (control) and treated orally with ALA (200 mg/kg after CLP) or vehicle. Animals were divided into sham + saline, sham + ALA, CLP + saline and CLP + ALA groups. Twelve, 24 h and 10 days after surgery, the hippocampus, prefrontal cortex and cortex were obtained and assayed for levels of TNF-α and IL-1β, blood brain barrier (BBB) permeability, nitrite/nitrate concentration, myeloperoxidase (MPO) activity, thiobarbituric acid reactive species (TBARS) formation, protein carbonyls, superoxide dismutase (SOD) and catalase (CAT) activity and neurotrophins levels. Behavioral tasks were performed 10 days after surgery. ALA reduced BBB permeability and TNF-α levels in hippocampus in 24 h and IL-1β levels and MPO activity in hippocampus and prefrontal cortex in 24 h. ALA reduced nitrite/nitrate concentration and lipid peroxidation in 24 h in all structures and protein carbonylation in 12 and 24 h in hippocampus and cortex. CAT activity increased in the hippocampus and cortex in all times. ALA enhanced NGF levels in hippocampus and cortex and prevented cognitive impairment. Our data demonstrates that ALA reduces the consequences of polymicrobial sepsis in rats by decreasing inflammatory and oxidative stress parameters in the brain.

Studies to reveal the nature of interactions between catalase and curcumin using computational methods and optical techniques

Curcumin is an important antioxidant compound, and is widely reported as an effective component for reducing complications of many diseases. However, the detailed mechanisms of its activity remain poorly understood. We found that curcumin can significantly increase catalase activity of BLC (bovine liver catalase). The mechanism of curcumin action was investigated using a computational method. We suggested that curcumin may activate BLC by modifying the bottleneck of its narrow channel. The molecular dynamic simulation data showed that placing curcumin on the structure of enzyme can increase the size of the bottleneck in the narrow channel of BLC, and readily allow the access of substrate to the active site. Because of the increase of the distance between amino acids of the bottleneck in the presence of curcumin, the entrance space of substrate increased from 250Å3 to 440Å3.In addition, the increase in emission of intrinsic fluorescence of BLC in presence of curcumin demonstrated changes in tertiary structure of catalase, and possibility of less quenching. We also used circular dichroism (CD) spectropolarimetry to determine how curcumin may alter the enzyme secondary structure. Catalase spectra in the presence of various concentrations of curcumin showed an increase in the amount of α-helix content.

Targeting Oxidative Stress, Cytokines and Serotonin Interactions Via Indoleamine 2, 3 Dioxygenase by Coenzyme Q10: Role in Suppressing Depressive Like Behavior in Rats.

Depression is a major health problem in which oxidative stress and inflammation are inextricably connected in its pathophysiology. Coenzyme Q10 (CoQ10) is an important anti-oxidant compound with anti-inflammatory and neuro-protective properties. This study was designed to investigate the hypothesis that CoQ10 by its anti-oxidant and anti-inflammatory potentials can alleviate depressive- like behavior by restoring the balance of the tryptophan catabolites kynurenine/serotonin toward the serotonin pathway by down-regulation of hippocampal indoleamine 2,3-dioxygenase 1 (IDO-1). Depressive-like behavior was induced by chronic unpredictable mild stress (CUMS) protocol including food or water deprivation, cage tilting, reversed light cycle etc. Male Wistar rats were randomly divided into five groups; Control, CUMS, CUMS and CoQ10 (50,100 and 200mg/kg/day i.p. respectively) groups. CoQ10 effects on different behavioral and biochemical tests were analyzed. CoQ10 showed significant antidepressant efficacy, as evidenced by significantly decreased stress induced changes to forced swimming challenge and open field test, as well as attenuating raised corticosterone level and adrenal glands weight. The anti-oxidant effect of CoQ10 was exhibited by its ability to significantly reduce hippocampal elevated malondialdehyde and 4-hydroxynonenal levels and elevate the reduced glutathione and catalase levels. CoQ10 significantly reduced different pro-inflammatory cytokines levels including interleukin (IL)-1β, IL-2, IL-6 and tumor necrosis factor-α. It suppressed hippocampal IDO-1 and subsequent production of kynurenine and enhanced the hippocampal contents of tryptophan and serotonin. Immunohistochemical analysis revealed that CoQ10 was able to attenuate the elevated microglial CD68 and elevate the astrocyte glial fibrillary acidic protein compared to CUMS group. CoQ10 exhibited antidepressant-like effects on rats exposed to CUMS. This could be attributed to its ability to reduce IDO-1 leading to shift the balance of the Kynurenine/ serotonin toward the serotonin pathway.

Identification and characterization of phenolic antioxidant compounds from brown Irish seaweed Himanthalia elongata using LC-DAD–ESI-MS/MS

This study investigated Himanthalia elongata Irish seaweed as a natural resource for antioxidant compounds. The phenolic compounds from the seaweed were extracted using 60% (v/v) aqueous methanol and the crude methanolic extract was purified with liquid–liquid partition (LLP) followed by column chromatography (CC). Among the purified fractions/sub-fractions, LLP-CC-ethyl acetate sub-fraction exhibited the highest DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging (EC50, 2.4 mg/g) and lipid peroxidation (LPO) scavenging capacity (97.7%). Rapid characterization of the same sub-fraction by LC-DAD–ESI-MS/MS identified a total of 8 phenolic compounds namely hydroxybenzaldehyde (meta/para), phloroglucinol, kaempferol, cirsimaritin, gallic acid 4-O-glucoside, carnosic acid and gallic acid. The purified sub-fractions showed higher antioxidant capacity (P < 0.05) than the reference ascorbic acid, suggesting its possible application in foods, pharmaceuticals and cosmetics for health promotion. Contributions of the study include identification of compounds (except gallic acid) that have not previously been reported in H. elongata, identifying it as a rich source of phenolic antioxidant compounds. According to the CE 258/97 regulation, algae are considered as new foods, and could also be considered as functional foods or a source of functional ingredients. This regulation allows the food industry to include seaweeds as raw or its constituents in the formulation of food products. Therefore, much attention nowadays has been focused on harnessing seaweed and its bioactive compounds for potential pharmaceuticals, nutraceutical, cosmetics and biotechnology applications. This study explores the potential of H. elongata Irish seaweed as a natural source of commercially important antioxidant compounds for possible application in food and dietary supplementation products. The crude extract is first purified and then the most active fraction was characterized further. The identified phenolic antioxidant compounds can constitute a new move in the understanding of the health benefits of H. elongata seaweed and the species can be considered as substantial alternate for functional ingredients in food and medicinal preparations.

The Toluene o-Xylene Monooxygenase Enzymatic Activity for the Biosynthesis of Aromatic Antioxidants

Monocyclic phenols and catechols are important antioxidant compounds for the food and pharmaceutic industries; their production through biotransformation of low-added value starting compounds is of major biotechnological interest. The toluene o-xylene monooxygenase (ToMO) from Pseudomonas sp. OX1 is a bacterial multicomponent monooxygenase (BMM) that is able to hydroxylate a wide array of aromatic compounds and has already proven to be a versatile biochemical tool to produce mono- and dihydroxylated derivatives of aromatic compounds. The molecular determinants of its regioselectivity and substrate specificity have been thoroughly investigated, and a computational strategy has been developed which allows designing mutants able to hydroxylate non-natural substrates of this enzyme to obtain high-added value compounds of commercial interest. In this work, we have investigated the use of recombinant ToMO, expressed in cells of Escherichia coli strain JM109, for the biotransformation of non-natural substrates of this enzyme such as 2-phenoxyethanol, phthalan and 2-indanol to produce six hydroxylated derivatives. The hydroxylated products obtained were identified, isolated and their antioxidant potential was assessed both in vitro, using the DPPH assay, and on the rat cardiomyoblast cell line H9c2. Incubation of H9c2 cells with the hydroxylated compounds obtained from ToMO-catalyzed biotransformation induced a differential protective effect towards a mild oxidative stress induced by the presence of sodium arsenite. The results obtained confirm once again the versatility of the ToMO system for oxyfunctionalization reactions of biotechnological importance. Moreover, the hydroxylated derivatives obtained possess an interesting antioxidant potential that encourages the use of the enzyme for further functionalization reactions and their possible use as scaffolds to design novel bioactive molecules.

Differences in the carotenoid profile of commercially available organic and conventional tomato-based products

BACKGROUND: Carotenoids are important antioxidant compounds in the human diet. Due to their constrained polyene structure, carotenoids can exist in cis and trans isomeric form. In ketchups and tomato juices, all-trans isomeric forms are predominant. OBJECTIVE: The aim of this study was to compare the carotenoid content and lipophilic antioxidant capacity of organic and conventional tomato-based products (tomato juices and ketchups) available on the market. METHODS: Liquid chromatography coupled to mass spectrometry in tandem mode (LC-MS/MS) and HPLC-UV were used for the identification and quantification of individual carotenoids. RESULTS: A comparative analysis of ketchups and tomato juices produced by conventional and organic systems showed statistically higher levels (P

Seed Coat Shininess in Phaseolus vulgaris: Rescuing a Neglected Trait by Its Screening on Commercial Lines and Landraces

Seeds with shiny seed coat in common bean (Phaseolus vulgaris L.) are normally rejected by consumers due to their difficult cooking, however they can prevent insects and pathogens injuries. Seed coat shininess is known to be conditioned by the Asp gene with the dominant form and is also influenced by the J locus. The latter influences seed coat color and pattern and has been considered a precursor for proanthocyanidin only in the presence of the dominant allele. This work aimed at performing a series of morphological, biochemical and genetic analyses for screening seed coat shininess in common bean. We showed Asp and J can be easily distinguished. Colorimeter data (L*a*b* system) can somehow provide a quantitative differentiation for seed coat shininess based on the L* variable. Palisade epidermis length and seed coat roughness profiles obtained through electronic microscopy were good indicators for Asp phenotyping. Water uptake was affected by shininess but is probably influenced by more genes, even J, or due physiological responses. A vanillin-HCl test showed to be a suitable method for tracing condensed tannins. AFLP markers partially allowed the categorization of shininess phenotypic classes. These results could be helpful regarding selection purposes and breeding. Therefore, favorable selection to Asp would lead to better resistance to pathogens and insects. J, instead, could be selected for nutritional purposes, since proanthocyanidins are important anti-oxidant and anti-carcinogenic compounds.

Production of caffeic, chlorogenic and rosmarinic acids in plants and suspension cultures of Glechoma hederacea

Glechoma hederacea L. (Lamiaceae) is a perennial plant, which is distributed widely in Europe, Asia and America. Important anti-oxidant compounds are caffeic acid esters like rosmarinic acid (RA) and chlorogenic acid (CA). Phenylalanine ammonia-lyase (PAL) and rosmarinic acid synthase (RAS, 4-coumaroyl-CoA:hydroxyphenyllactic acid hydroxycinnamoyltransferase) contribute to the formation of RA. Our aim in this study was to follow the accumulation of RA, CA and caffeic acid in a suspension culture of G. hederacea. Growth, medium and secondary metabolism parameters were determined during a culture period of 14 days. The maximal PAL activity was observed on day 5 and the maximal RAS activity on day 8. The RA content was exceedingly high and reached 25.9% of the dry mass on day 7. Caffeic acid and CA contents remained rather low. Furthermore, the presence of RA, CA and caffeic acid and the expression patterns of RAS and hydroxycinnamoyl-CoA:shikimate hydroxycinnamoyltransferase (HST), an important enzyme of monolignol formation, in leaves, flowers, stems and roots of naturally grown G. hederacea were assessed. The expression of RAS and HST genes was detectable in all organs except roots. Flowers accumulated 12.5% RA in their dry mass, leaves, stems and roots about 1%. CA was highest in leaves (2.0%), while it was at 1.6% in flowers, 1.3% in stems and almost undetectable in roots. The caffeic acid content remained at or below 0.4% of the dry weight in all organs.

Antimicrobial, antioxidant, anti-inflammatory activities and phytoconstituents of extracts from the roots of Dissotis thollonii Cogn. (Melastomataceae)

BackgroundDissotis thollonii Cogn. belonging to the Malastomataceae family is used in the West Region of Cameroon for the treatment of inflammation, kidney diseases, pregnancy control and sinusitis. Despite the traditional use of this plant, no scientific report or information was found in the literature regarding neither its biological activity nor its chemical constituents. Aim of the studyThe present work was designed to determine the antimicrobial, antioxidant and anti-inflammatory activities of different extracts of the roots of D. thollonii Cogn. as well as the isolation and identification of the chemical constituents of this plant. Materials and methodsThe tests for antimicrobial, antioxidant and anti-inflammatory activities were performed over the MeOH, EtOAc, n-BuOH and aqueous extracts. Compounds were isolated from EtOAc and n-BuOH extracts of the roots of D. thollonii Cogn. through column chromatography and their structures were determined by means of NMR and MS analysis, and published data. ResultsAccording to the antimicrobial and antioxidant assays, the EtOAc and n-BuOH extracts were submitted to further separation and purification. This led to the isolation of twelve compounds identified as 3,3′-di-O-methylellagic acid 4′-O-β-D-xylopyranoside 1, 3-O-methylellagic acid 4′-O-β-D-arabinopyranoside 2, casuarinin 3, betulinic acid 4, β-sitosterol-3-O-D-glucopyranosyl-6′-mirystate 5, cellobiosylsterol 6, β-sitosterol 7, β-sitosterol-3-O-β-D-glucopyranoside 8, arjunolic acid 9, 3,3′-di-O-methylellagic acid 10, ellagic acid 11, and 3,3′-di-O-methylellagic acid 4′-O-β-D-glucopyranoside 12. The EtOAc extract was the only antimicrobial active sample [diameter of the zone of inhibition (DZI) of 10mm against Staphyloccocus aureus] among all the tested extracts. The analysis of fractions of this extract revealed the presence of bioactive compounds with a described antimicrobial activity such as β-sitosterol, β-sitosterol-3-O-β-D-glucopyranoside and arjunolic acid. By using Trolox as the standard drug, all extracts showed antioxidant activity against DPPH in the following order of scavenging ability: Trolox>nBuOH>EtOAc>MeOH>WE (water extract). The ABTS•+ scavenging ability was similar to that found for the DPPH assay, being Trolox>n-BuOH>MeOH>EtOAc>WE. Along with the DPPH and ABTS assays, the FRAP assay showed the scale n-BuOH>MeOH>WE>EtOAc. The phytochemical study of the EtOAc and n-BuOH extracts revealed the presence of important known antioxidant compounds such as ellagic acid derivatives, arjunolic acid, betulinic acid and β-sitosterol. The anti-inflammatory properties of D. thollonii extracts were investigated using RAW 264.7 murine macrophage cells. The MeOH extract reduced the stimulated NO production in a concentration-dependent manner. 86% reduction was observed at the highest tested concentration of 100μg/ml (IC50=5.9μg/ml). The n-BuOH extract showed higher dose dependent reduction of NO formation (IC50=6.5μg/ml) than the EtOAc extract (IC50=18.1μg/ml), whereas the water extract had no significant influence on the NO production. All the extracts did not have any influence on the macrophage viability. The phytochemical investigation of the EtOAc and n-BuOH extracts revealed that the main compounds identified do have potent anti-inflammatory properties. ConclusionThe biological and phytochemical characterization of the root extracts of D. thollonii validates the use of this plant for the treatment of inflammation and sinusitis, thus providing evidence that this plant extracts, as well as some of the isolated compounds, might be potential sources of antioxidant and anti-inflammatory drugs.

High-performance thin-layer chromatographic analysis of antioxidants present in different parts of Saraca asoca (Roxb.) de Wilde

ObjectiveGallic acid, ellagic acid and quercetin are the important antioxidant compounds of Saraca asoca (Roxb.) de Wilde (Caesalpiniaceae). This report describes the determination of free radical scavenging activity in different plant parts (of S. asoca) by DPPH assay with correlation, and quantification of gallic acid, ellagic acid and quercetin in different plant parts by a simple, sensitive and validated HPTLC method. MethodologyMethanolic extracts of bark, leaf and flowers of S. asoca were investigated for their antioxidant potential with the aid of DPPH assay followed by HPTLC analysis for quantitative evaluation of antioxidants (gallic acid, ellagic acid, and quercetin) in different plant parts. ResultsHPTLC analysis exhibited high amount of gallic acid and quercetin in flower (0.320% and 0.11% w/w respectively) and high amount of ellagic acid in bark (0.4805% w/w) which corresponds to low IC50 values of 6.83 ± 0.07 μg/ml and 6.6 ± 0.10 μg/ml respectively, indicating the remarkable antioxidant activity of these two plant parts whereas moderate amount of gallic acid (0.164 %w/w) and very low amount of quercetin (0.0445% w/w) and ellagic acid (0.04% w/w) correlate high IC50 value of 28.6 ± 0.62 μg/ml representing its poor antioxidant potential. ConclusionConsumption of bark and flower of S. asoca could be beneficial by virtue of its high antioxidant activity. The flower and bark may be considered as a source of gallic acid and ellagic acid respectively. The presence of moderate amount of gallic acid in leaf can be an alternative source.

Carotenoids from Foods of Plant, Animal and Marine Origin: An Efficient HPLC-DAD Separation Method.

Carotenoids are important antioxidant compounds, present in many foods of plant, animal and marine origin. The aim of the present study was to describe the carotenoid composition of tomato waste, prawn muscle and cephalothorax and avian (duck and goose) egg yolks through the use of a modified gradient elution HPLC method with a C30 reversed-phase column for the efficient separation and analysis of carotenoids and their cis-isomers. Elution time was reduced from 60 to 45 min without affecting the separation efficiency. All-trans lycopene predominated in tomato waste, followed by all-trans-β-carotene, 13-cis-lutein and all-trans lutein, while minor amounts of 9-cis-lutein, 13-cis-β-carotene and 9-cis-β-carotene were also detected. Considering the above findings, tomato waste is confirmed to be an excellent source of recovering carotenoids, especially all-trans lycopene, for commercial use. Xanthophylls were the major carotenoids of avian egg yolks, all-trans lutein and all-trans zeaxanthin in duck and goose egg yolk, respectively. In the Penaeus kerathurus prawn, several carotenoids (zeaxanthin, all-trans-lutein, canthaxanthin, cryptoxanthin, optical and geometrical astaxanthin isomers) were identified in considerable amounts by the same method. A major advantage of this HPLC method was the efficient separation of carotenoids and their cis-isomers, originating from a wide range of matrices.

Differences in the carotenoid content of ketchups and gazpachos through HPLC/ESI(Li+)‐MS/MS correlated with their antioxidant capacity

Carotenoids are important antioxidant compounds in the human diet. Owing to their constrained polyene structure, carotenoids can exist in cis and trans isomeric forms that can be difficult to differentiate in natural samples. In ketchups and gazpachos, all-trans isomeric forms are predominant. However, during thermal processing, cis isomers are formed. Therefore the determination of carotenoid isomers is required for the assessment of the nutritional value of foods. The main carotenoid found in ketchups was trans-lycopene, whereas in gazpachos a higher contribution to the total carotenoid content was made by other carotenoids such as 5-, 9- and 13-cis-lycopene, lutein, β-carotene and α-carotene. Ketchups exhibited the highest lipophilic antioxidant content owing to their higher content of trans-lycopene, the main carotenoid in tomatoes. Direct analysis of carotenoids by electrospray ionisation mass spectrometry (ESI-MS) often produces poor results requiring offline time- and sample-consuming derivatisation techniques. Therefore in this work a simple ESI-MS approach is described for the direct analysis of carotenoids in ketchups and gazpachos using the post-column addition of lithium chloride to promote the cationisation of carotenoids. To the best of the authors' knowledge, this paper presents for the first time the identification of 5-, 9- and 13-cis-lycopene in ketchups and gazpachos.

Differential Regulation of Serine Acetyltransferase Is Involved in Nickel Hyperaccumulation in Thlaspi goesingense

When growing in its native habitat, Thlaspi goesingense can hyperaccumulate 1.2% of its shoot dry weight as nickel. We reported previously that both constitutively elevated activity of serine acetyltransferase (SAT) and concentration of glutathione (GSH) are involved in the ability of T. goesingense to tolerate nickel. A feature of SAT is its feedback inhibition by l-cysteine. To understand the role of this regulation of SAT by Cys on GSH-mediated nickel tolerance in T. goesingense, we characterized the enzymatic properties of SATs from T. goesingense. We demonstrate that all three isoforms of SAT in T. goesingense are insensitive to inhibition by Cys. Further, two amino acids (proline and alanine) in the C-terminal region of the cytosolic SAT (SAT-c) from T. goesingense are responsible for converting the enzyme from a Cys-sensitive to a Cys-insensitive form. Furthermore, the Cys-insensitive isoform of SAT-c confers elevated resistance to nickel when expressed in Escherichia coli and Arabidopsis thaliana, supporting a role for altered regulation of SAT by Cys in nickel tolerance in T. goesingense.

Evaluation of Antioxidant Compounds and Total Sugar Content in a Nectarine [Prunus persica (L.) Batsch] Progeny

Epidemiological studies suggest that consumption of fruit rich in phenolic compounds is associated with health-protective effects due to their antioxidant properties. For these reasons quality evaluation has become an important issue in fruit industry and in breeding programs. Phytochemical traits such as total phenolics, flavonoids, anthocyanins, L-ascorbic acid, sugar content and relative antioxidant capacity (RAC) were analyzed over four years in flesh fruit of an F1 population “Venus” × “Big Top” nectarines. Other traits such as harvesting date, yield, fruit weight, firmness, soluble solids concentration (SSC), pH, titratable acidity (TA) and ripening index (RI) were also determined in the progeny. Results showed high variability among genotypes for all analyzed traits. Total phenolics and flavonoids showed significant positive correlations with RAC implying that both are important antioxidant bioactive compounds in peaches. We found genotypes with enhanced antioxidant capacity and a better performance than progenitors, and in consequence the best marketability.

Antioxidant Potential of Two Red Seaweeds from the Brazilian Coasts

In this work, in vitro antioxidant activity of two Brazilian red seaweeds, Gracilaria birdiae and Gracilaria cornea, was characterized. The total phenolic content, the radical-scavenging activity and the antioxidant activity were determined in two solvent extracts of the algae. Liquid chromatography-mass spectrometry (LC-MS/MS) allowed identification of important antioxidant compounds. The ethanol extract of G. birdiae was found to have the highest value of total phenolic content: 1.13 mg of gallic acid equiv (GAE)/g of extract. The radical-scavenging activity of G. birdiae and G. cornea extracts has been evaluated at different extract concentrations; the IC(50) values of ethanolic extracts of G. cornea and G. birdiae were 0.77 and 0.76 mg mL(-1), respectively, while for methanolic extracts, the IC(50) values of G. cornea and G. birdiae were 0.86 and 0.76 mg mL(-1), respectively. The antioxidant activities of these two seaweeds' extracts as assessed by the β-carotene-linoleic acid assay were equally high, achieving values of β-carotene oxidation inhibition of up to 40%. Finally, in the methanolic extracts, LC-MS/MS allowed identification in both algae of two important antioxidants: apigenin and gallic acid.

Impact of postharvest methyl jasmonate treatment on the volatile composition and flavonol content of strawberries

Although strawberry aroma is very complex, certain compounds have been described as main contributors, i.e. furanones, aldehydes, alcohols, sulfur compounds and particularly methyl and ethyl esters. In addition, strawberries possess potent antioxidant activity because of their high content of phenolic compounds. Among them, flavonols are highlighted as important antioxidant compounds in strawberry. The objective of this study was to assess the effect of methyl jasmonate (MJ) on the composition of the major contributors to aroma and on the content of certain flavonols in strawberry fruits. The levels of all studied volatile compounds were significantly affected by MJ treatment, though the individual effect differed according to the specific compound considered. Most of them increased significantly (P < 0.05), except methyl butanoate, which always showed higher levels in untreated strawberries. In contrast to aroma compounds, the change in the concentration of flavonols (i.e. myricetin, quercetin and kaempferol) was not significant in MJ-treated strawberries. Considering the health-promoting activity of these compounds, further investigations on the experimental conditions related to the treatment are required to control flavonol bioformation by means of MJ. The exogenous application of MJ vapour to strawberry enhances, in general, the production of the most relevant aroma-active compounds. On the contrary, MJ treatment does not appear to influence the levels of myricetin, quercetin and kaempferol. Thus postharvest MJ treatment is proposed as an approach to obtain improved strawberry fruits in terms of sensory quality and health-promoting properties.

Effect of freeze-drying and oven-drying on volatiles and phenolics composition of grape skin

Grape skins are the part of the fruit with the highest amount of volatile and polyphenolic compounds. Volatile compounds give the fruit and other grape derivatives their flavour. Polyphenolic compounds are responsible for the colour of the fruit, juice and wine, and also act as very important natural antioxidant compounds. Dehydration is a method used to prevent the damage of these compounds over time. Nevertheless, in the case of volatile compounds, removing water can cause compound degradation or the evaporation of such compounds. This work studied two drying methods, freeze-drying and oven-drying, at 60 °C, as skin preservation methods. The skins from two grape varieties, Carménère and Cabernet Sauvignon, were dried. Many volatile compounds, which are of interest in the aroma profile, were identified in both varieties as terpenes (linalool, etc.), sesquiterpenes (farnesol), norisoprenoids (vitispirane, etc.), C 6 alcohols (1-hexanol, etc.), etc., and their amount decreased significantly with the oven-drying method, in contrast to the freeze-drying method. Both phenolic compounds, anthocyanins and flavonols, were identified in fresh and dehydrated samples, thus resulting in the freeze-drying method being less aggressive than oven-drying methods.

Phenolic metabolism of Matricaria chamomilla plants exposed to nickel

We examined accumulation of phenolic acids, total soluble phenolics and flavonoids, and activities of phenolic metabolism-related enzymes (shikimate dehydrogenase (SKDH), phenylalanine ammonia-lyase (PAL), cinnamyl alcohol dehydrogenase (CAD), polyphenol oxidase (PPO)) in Matricaria chamomilla plants exposed to 3, 60 and 120 microM of nickel (Ni) for 10 days. Ni showed low toxicity as indicated by unaltered content of total soluble phenolics in the leaf rosettes. In the roots, the effects of Ni were more visible, including increased total phenolics and PAL activity, but a decrease in PPO activity was observed. CAD activity was not affected by any of the Ni concentrations. Cinnamic acid derivatives were affected more than benzoic acid derivatives. Accumulation of chlorogenic acid, an important antioxidant compound, was enhanced by Ni treatment (ca. 4-fold in 120 microM Ni). Accumulation of protocatechuic acid, a phenol with high chelating strength, even decreased in the leaf rosettes. These observations are discussed in connection to antioxidative properties of phenolic metabolites and previously tested metals (cadmium and copper).

Ultrasound Mediates the Release of Curcumin from Microemulsions

Ultrasound is a powerful noninvasive modality for biomedical imaging, and holds much promise for noninvasive drug delivery enhancement and targeting. However, the optimal design of sound sensitive carriers is still poorly understood. In this study, curcumin, an important natural antioxidant and anticancer compound, was stably entrapped into microemulsion droplets with average size 20-35 nm. To release curcumin, low frequency (40 kHz) ultrasound at an intensity of 3.8 or 9.8 W/cm2 was applied to the microemulsions, using a probe sonicator. On insonation, much of the curcumin was released from the microemulsions and formed insoluble aggregates, as evidenced by decreased UV-vis absorption at 420 nm. The initial release rate (assayed by the rate of change of absorption) was as high as 0.11 microg/s (1.87%/sec) in phosphate buffered saline solution at neutral pH, but decreased at acidic pH. Interestingly, lower curcumin loading led to a more rapid release under insonation. Measurements of emulsion droplet size implicate droplet reorganization (fusion or fission) as an important contributing mechanism for the ultrasonic release of this compound. Although cargo in microemulsions is partitioned, rather than encapsulated (as in, for example, liposomes), these new results demonstrate that microemulsion carriers are feasible for some ultrasonic drug delivery applications.