Phytochemical profile of main antioxidants in different fractions of purple and blue wheat, and black barley

Two pigmented wheat genotypes (blue and purple) and two black barley genotypes were fractionated in bran and flour fractions, examined, and compared for their free radical scavenging properties against 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical cation (Trolox equivalent antioxidant capacity, TEAC), ferric reducing antioxidant power (FRAP), total phenolic content (TPC), phenolic acid composition, carotenoid composition, and total anthocyanin content. The results showed that fractionation has a significant influence on the antioxidant properties, TPC, anthocyanin and carotenoid contents, and phenolic acid composition. Bran fractions had the greatest antioxidant activities (1.9-2.3 mmol TEAC/100 g) in all four grain genotypes and were 3-5-fold higher than the respective flour fractions (0.4-0.7 mmol TEAC/100 g). Ferulic acid was the predominant phenolic acid in wheat genotypes (bran fractions) while p-coumaric acid was the predominant phenolic acid in the bran fractions of barley genotypes. High-performance liquid chromatography analysis detected the presence of lutein and zeaxanthin in all fractions with different distribution patterns within the genotypes. The highest contents of anthocyanins were found in the middlings of black barley genotypes or in the shorts of blue and purple wheat. These data suggest the possibility to improve the antioxidant release from cereal-based food through selection of postharvest treatments.     

Denitrifikation eines gemüsebaulich genutzten Bodens in Abhängigkeit von der Einarbeitung frischer Erntereste

Denitrification losses from a horticultural soil as affected by incorporation of fresh plant residues Denitrification in the A_p-horizon of a Luvisol under horticulture as affected by fresh cauliflower residues (Brassica oleracea L. var. botrytis) was measured using the acetylene inhibition technique. The residues were chopped and ploughed in 25 cm deep. Denitrification rates, soil temperature, moisture, nitrate and watersoluble carbon were determined from the end of July until the end of September. One day after incorporation of plant residues the denitrification rate showed a rapid increase to the highest value (5.15 kg N · ha^?1 · day^?1) of the experimental period. During the following 57 days the rates declined to the level of the untreated control. The highest denitrification rates occurred in the experimental sites which received plant residues. The estimated N-loss for the whole experimental period (57 days) totalled 43.6 kg N · ha^?1 in the treatment with plant residues and 2 kg N · ha^?1 in the treatment without plant residues. Coefficients of variation of denitrification rates were high (29–206%). Within the treatment ‘with plant residues’ denitrification rate and watersoluble carbon were positively correlated.     

Fate of PAHs and Hetero-PAHs during Biodegradation in a Model Soil/Compost-System: Formation of Extractable Metabolites

The formation of extractable metabolites of PAHs andhetero-PAHs during biodegradation was investigated in three artificially contaminated AhA1-horizon/compost-mixtures spikedwith (a) a PAH-mixture consisting of nine compounds, (b) a hetero-PAH-mixture consisting of ten compounds, and (c) a mixture of these nine PAHs and ten hetero-PAHs. 30 PAH-metabolites and 4 hetero-PAHs metabolites were identified byHPLC-DAD and GC-MSD, predominantly aromatic ketones, quinones,hydroxylated and dihydroxylated compounds. Several of thesemetabolites such as 1-acenaphthenone, 4-hydroxy-9-fluorenone,9,10-phenanthrenedione, 1-hydroxyacenaphthene, dihydroxyacenaphthene or the hetero-PAH-metabolites 2-hydroxyquinoline, dibenzothiophenesulfoxide, dibenzothiophenesulfone, and hydroxydibenzofuran have not beenidentified in previous soil degradation studies. The vastmajority of extractable metabolites showed only short-timeaccumulation followed by either further degradation orformation of bound residues, respectively. In the PAH- andhetero-PAH-contaminated soil systems formation of metaboliteswas delayed due to the delay in degradation of most parentcompounds in these soil systems. As some of the PAH-metabolitesshowed considerable accumulation or persistence at the end ofthe investigation period, further studies including toxicitytesting of metabolites are required to finally assess therelevance of extractable metabolites during bioremediation ofcontaminated soil.     

The Skeletal Amino Acid Composition of the Marine Demosponge Aplysina cavernicola

It has been discovered during the past few years that demosponges of the order Verongida such as Aplysina cavernicola exhibit chitin-based skeletons. Verongida sponges are well known to produce bioactive brominated tyrosine derivatives. We could recently demonstrate that brominated compounds do not exclusively occur in the cellular matrix but also in the skeletons of the marine sponges Aplysina cavernicola and Ianthella basta. Our measurements imply that these yet unknown compounds are strongly, possibly covalently bound to the sponge skeletons. In the present work, we determined the skeletal amino acid composition of the demosponge A. cavernicola especially with respect to the presence of halogenated amino acids. The investigations of the skeletons before and after MeOH extraction confirmed that only a small amount of the brominated skeleton-bound compounds dissolves in MeOH. The main part of the brominated compounds is strongly attached to the skeletons but can be extracted for example by using Ba(OH)₂. Various halogenated tyrosine derivatives were identified by GC-MS and LC-MS in these Ba(OH)₂ extracts of the skeletons.     

Sulfated Galactofucan from the Brown Alga Saccharina latissima—Variability of Yield,Structural Composition and Bioactivity

The fucose-containing sulfated polysaccharides (SP) from brown algae exhibit a wide range of bioactivities and are, therefore, considered promising candidates for health-supporting and medicinal applications. A critical issue is their availability in high, reproducible quality. The aim of the present study was to fractionate and characterize the SP extracted from Saccharina latissima (S.l.-SP) harvested from two marine habitats, the Baltic Sea and North Atlantic Ocean, in May, June and September. The fractionation of crude S.l.-SP by anion exchange chromatography including analytical investigations revealed that S.l.-SP is composed of a homogeneous fraction of sulfated galactofucan (SGF) and a mixture of low-sulfated, uronic acid and protein containing heteropolysaccharides. Furthermore, the results indicated that S.l. growing at an intertidal zone with high salinity harvested at the end of the growing period delivered the highest yield of S.l.-SP with SGF as the main fraction (67%). Its SGF had the highest degree of sulfation (0.81), fucose content (86.1%) and fucose/galactose ratio (7.8) and was most active (e.g., elastase inhibition: IC₅₀ 0.21 μg/mL). Thus, S.l. from the North Atlantic harvested in autumn proved to be more appropriate for the isolation of S.l.-SP than S.l. from the Baltic Sea and S.l. harvested in spring, respectively. In conclusion, this study demonstrated that habitat and harvest time of brown algae should be considered as factors influencing the yield as well as the composition and thus also the bioactivity of their SP.     

Evaluation of the Effects of Fucoidans from Fucus Species and Laminaria hyperborea against Oxidative Stress and Iron-Dependent Cell Death

Fucoidans are algal polysaccharides that exhibit protective properties against oxidative stress. The aim of this study was to investigate different fucoidans from brown seaweeds for their ability to protect against iron-dependent oxidative stress (ferroptosis), a main hallmark of retinal and brain diseases, including hemorrhage. We investigated five new high-molecular weight fucoidan extracts from Fucus vesiculosus, F. serratus, and F. distichus subsp. evanescens, a previously published Laminaria hyperborean extract, and commercially available extracts from F. vesiculosus and Undaria pinnatifida. We induced oxidative stress by glutathione depletion (erastin) and H₂O₂ in four retinal and neuronal cell lines as well as primary cortical neurons. Only extracts from F. serratus, F. distichus subsp. evanescens, and Laminaria hyperborea were partially protective against erastin-induced cell death in ARPE-19 and OMM-1 cells, while none of the extracts showed beneficial effects in neuronal cells. Protective fucoidans also attenuated the decrease in protein levels of the antioxidant enzyme GPX4, a key regulator of ferroptosis. This comprehensive analysis demonstrates that the antioxidant abilities of fucoidans may be cell type-specific, besides depending on the algal species and extraction method. Future studies are needed to further characterize the health-benefiting effects of fucoidans and to determine the exact mechanism underlying their antioxidative abilities.     

Tentative Avenanthramide‐Modifying Enzyme in Oats

A decrease of the concentration of the synthetic avenanthramide N‐(4′‐hydroxy‐(E)‐cinnamoyl)‐5‐hydroxyanthranilic acid in a buffered slurry of milled oat groats (Avena sativa L.) was temperature and pH‐dependent, with a maximum rate at 30°C and pH 9. The reaction was inhibited in the presence of 2‐mercaptoethanol, acetic acid and at high temperature; suggestive of enzymatically catalyzed nature. Among eight different synthetic avenanthramides tested, the tentative enzyme had highest affinity for avenanthramides comprising caffeic and p‐coumaric acids and lowest for those comprising sinapic and ferulic acids. The activity was found in samples from several oat cultivars and was equally pronounced in both bran and endosperm flour of oats. Steeping of oat grains did not influence the reaction.