The syntheses of aromatic monoamines and aliphatic polyamines (PAs) are responsive to environmental stresses, with some modulating aspects of plant defense. Conjugation of amines to hydroxycinnamic ...acids (HCAs) generates HCA amides (HCAAs), with the conjugates possessing properties from both compounds. Conjugation may reduce the polarity of the resulting metabolite and assist in translocation, stability, and compartmentalization. Recent metabolomic insights identified HCAAs as biomarkers during plant–pathogen interactions, supporting a functional role in defense. The conjugates may contribute to regulation of the dynamic metabolic pool of hydroxycinnamates. This review highlights the occurrence of aromatic amines (AAs) and PAs in stress metabolism, conjugation to HCAs, and the roles of HCAAs during host defense, adding emphasis on their involvement in hydrogen peroxide (H2O2) production and cell-wall strengthening.
The aromatic amine (AA) and polyamine (PA) content of plant cells is highly responsive to developmental and environmental signals. AAs originate from aromatic amino acids, linking primary and secondary metabolism. Correspondingly, PAs represent a molecular nexus for growth, survival, and specialized metabolism that form part of a complex signaling network.The metabolism of hydroxycinnamic acids (HCAs) is interlaced with metabolic pathways involved in defense signaling and equally, the PAs are upregulated in response to abiotic and biotic stresses. Conjugation of these free acids and amines generates HCA amides (HCAAs) and bridges two classes of protective molecules.Recent metabolomic insights have highlighted PAs, AAs, and HCAAs as biomarkers during plant–microbe interactions, suggesting a protective function or a defensive role for the HCAAs.
Summary
Grass cell walls have hydroxycinnamic acids attached to arabinosyl residues of arabinoxylan (AX), and certain BAHD acyltransferases are involved in their addition. In this study, we ...characterized one of these BAHD genes in the cell wall of the model grass Setaria viridis. RNAi silenced lines of S. viridis (SvBAHD05) presented a decrease of up to 42% of ester‐linked p‐coumarate (pCA) and 50% of pCA‐arabinofuranosyl, across three generations. Biomass from SvBAHD05 silenced plants exhibited up to 32% increase in biomass saccharification after acid pre‐treatment, with no change in total lignin. Molecular dynamics simulations suggested that SvBAHD05 is a p‐coumaroyl coenzyme A transferase (PAT) mainly involved in the addition of pCA to the arabinofuranosyl residues of AX in Setaria. Thus, our results provide evidence of p‐coumaroylation of AX promoted by SvBAHD05 acyltransferase in the cell wall of the model grass S. viridis. Furthermore, SvBAHD05 is a promising biotechnological target to engineer crops for improved biomass digestibility for biofuels, biorefineries and animal feeding.
Significance Statement
A BAHD acyltransferase gene was studied, and it was demonstrated that its suppression causes reduction of ester‐linked p‐coumaric acid in the cell walls of Setaria viridis. RNAi silenced lines had higher biomass digestibility with no alteration in the biomass production. Molecular dynamics simulation reinforced the evidence that SvBAHD05 is mainly responsible for the incorporation of p‐coumaric acid onto arabinoxylan, the main hemicellulose in grass cell walls.
Chitosan‐caffeic and chitosan‐ferulic acid conjugates are synthesized by carbodiimide method and characterized by UV, FTIR, and NMR spectroscopy. There are two obtained forms of conjugates: freshly ...synthesized and reconstituted freeze‐dried. A comparative study of the stability of various conjugate forms over time and under UV irradiation has been carried out. It has been shown that the absorption intensity of an aqueous solution of the freshly synthesized chitosan‐caffeic acid conjugate decrease in ~2 times during 20 weeks of storage, while the maximum rate of intensity decrease is observed during the first 40 days. The absorption intensity of the chitosan‐ferulic acid conjugate decrease by 6–7% during the entire storage period. It has been found that freeze‐dried powders of chitosan‐caffeic and chitosan‐ferulic acid conjugates are stable for at least 1 year. It has been established that freeze‐dried chitosan‐caffeic and chitosan‐ferulic acid conjugates are more stable under UV irradiation (in 4–8 and 1.4–1.9 times, respectively) compared to freshly synthesized ones. A comparative study of the influence of conjugates on barley seedlings (Hordeum vulgare L.) growth has been carried out.
This study introduces a comparative complex assay of photostability and phytotoxicity of caffeic and ferulic acids conjugated to chitosan. Conjugates were synthesized by carbodiimide method and characterized by UV, FTIR spectroscopy and NMR. An approach to the creation of a soluble powder as base of water‐miscible formulation of conjugates, stable during storage and UV irradiation and suitable for seed treatment was proposed.
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•Distribution of phenolic acids in vegetables and their health benefits are mapped.•Higher retention of phenolic acids is reported after vacuum processing and freezing.•Frying, ...grilling, boiling and steaming are detrimental to vegetable phenolic acids.•Storage of vegetables at lower temperatures retains higher phenolic acids.•The review indicates vegetables are potential source of phenolic acids in the diet.
Phenolic acids are the most prominent group of bioactive compounds present in various plant sources. Hydroxybenzoic acids and hydroxycinnamic acids, the aromatic secondary metabolites imparting typical organoleptic characteristics to food are the major phenolic acids, and they are linked to several health benefits. Fruit and beverage crops being the richer sources of phenolic acids have been studied in depth, but phenolic acids from vegetables are largely overlooked. Though lesser in quantity in many vegetables, there is a need to explore the health benefits of the phenolic acids present in them. In this review, the importance of vegetables as a significant source of phenolic acids is emphasized. Vegetables being easily accessible throughout the year and consumed in larger quantities compared to fruits in our daily diet will probably contribute to significant health benefits. Since vegetables are often processed before consumption, the changes in phenolic acids as influenced by processing methods are highlighted. Best processing methods, pre-treatments and storage conditions for higher retention of phenolic acids have been highlighted to minimize their losses. The phenolic acids in vegetables and their health benefits have been cluster mapped, which may facilitate further research for nutraceutical development for specific health concerns. The processing stability of phenolic acids coupled with higher consumption indicates that they may be a potential source of phenolic acids in the diet. It is expected that the popularization of vegetables as a source of phenolic acids in daily diet will help in ameliorating the adverse effect of some of the lifestyle diseases.
The effect of pitanga leaf extracts, as source of natural antioxidants, on physicochemical properties as well as lipid and protein oxidation of pork burgers during storage at 2 ± 1 °C, packed under ...modified atmosphere, was assessed. Formerly, the in vitro antioxidant and antimicrobial activities as well as the phenolic profile of pitanga leaf extracts were also studied. Thereafter, five samples were prepared, including control (without antioxidants), commercial synthetic antioxidant (BHT at 200 mg/kg) and three concentrations of pitanga leaf extracts: PLL (at 250 mg/kg), PLM (at 500 mg/kg) and PLH (at 1000 mg/kg). The predominant phenolic compounds identified in pitanga leaf extracts were hydroxycinnamic acids, followed by tyrosol and other phenolics (alkylmethoxyphenols, hydroxycoumarins and hydroxyphenylpropenes). Pitanga leaf extracts showed a high antioxidant and antimicrobial in vitro activity. The addition of pitanga leaf extracts improved the redness of pork burgers during the whole display. On the other hand, the addition of natural antioxidants decreased the lipid oxidation from day 7 till the end of storage period. Burgers with antioxidant showed a similar protein oxidation level, observing an inhibition between 36% and 49% compared to control treatment. From the results, it can be concluded that pitanga leaf extract is a good alternative to commercial synthetic antioxidants to improve the quality and extend the shelf-life of pork burgers.
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•Pitanga leaf extract is a good alternative to commercial antioxidant to extend the shelf-life of burgers•The main phenolics measured in pitanga leaf extract were hydroxycinnamics and tyrosols•The addition of pitanga leaf extracts improved the redness of pork burgers during the whole display•Pitanga leaf extract decreased the lipid and protein oxidation of pork burgers
We evaluated the antioxidant activity of natural polyphenols which gives high oxidative stability to the pecan oil. The in vitro DPPH radical scavenging, reducing power and total antioxidant activity ...of tested antioxidants demonstrated that tannic acid displayed the highest DPPH scavenging activity and provided the largest reducing power. During storage of pecan oil, based on oxidative stability tests, we further evaluated the protective effect of polyphenols and synthetic antioxidants on the oxidative stability of pecan oil. The results showed that caffeic acid inhibited oxidation of pecan oil effectively. Sesamol and catechin showed slight improvement in oxidative stability, while ferulic acid, erucic acid and rutin had no effect. Taken together, compared with synthetic antioxidants (TBHQ, BHT, BHA), caffeic acid was observed to be stronger than BHT and BHA and was close to TBHQ.
•The three major categories of phenolic compounds for evaluation of oxidative stability to the pecan oil.•Caffeic acid displayed the greatest oxidative stability against pecan oil.•Tannic acid showed the highest DPPH scavenging and total reducing power without affecting pecan oil oxidation.
Background.
Blue honeysuckle (
Lonicera caerulea
L
.
) is a valuable source of bioactive compounds (BAC) of polyphenolic nature and rare for horticultural berries iridoids, which have antioxidant, ...anti-inflammatory, antimicrobial and other properties and are widely used in the food, medical and cosmetic industries.
Materials and methods.
The berries of 20 released honeysuckle cultivars of Russian, Canadian and U.S. origin, reproduced at the I.V. Michurin Federal Science Center in Tambov Province, were studied for the content of the main BAC groups using modern methods (spectrophotometry, HPLC-UV, HPLC-RID, and HPLC-DAD-MS).
Results and discussion.
The main BAC groups (the content and profile of anthocyanins, proanthocyanidins, flavonols and flavones, hydroxycinnamic acids (HCA), iridoids, and organic acids) as well as mono- and disaccharides were studied in detail. A comparative study of the biological value of domestic and foreign honeysuckle cultivars was carried out.
Conclusions.
The study resulted in identifying the most promising cultivars of honeysuckle according to the content of the main BAC groups.
•33 compounds identified in Sambucus ebulus fruit tea using UPLC-DAD-ESI/MS/MS.•10 hydroxycinnamic acids, 9 of them reported to the first time in S. ebulus fruits.•12 newly established flavonol ...glucosides in S. ebulus fruits.•Resveratrol present in quantity higher that in red grape skin.•Catechin, epicatechin, proanthocyanidin di- and –trimers in considerable amounts.
The purpose of this study was to perform phytochemical analysis of tea from Sambucus ebulus fruits concerning hydroxycinnamic acids, flavonol glucosides, stilbenes and proanthocyanidin mono-, di- and trimers content. In total, 33 compounds were identified and quantified using UPLC-DAD-ESI/MS/MS system and the results are presented in mg/g dry weight (DW). Among analyzed hydroxycinnamic acids, 5-Caffeoylquinic acid (114.17 mg/g) was most abundant, followed by 3-p-Coumaroylquinic acid (50.33 mg/g) and 3-p-Feruloylquinic acid, p-Coumaric acid glucoside and 4-p-Coumaroylquinic acid (31.36 mg/g, 29.78 mg/g and 27.70 mg/g, respectively). Flavonol glucosides were represented predominantly by Quercetin-3-O-galactoside, Quercetin-3-O-rhamnosyl-galactoside Quercetin-3-O-glucoside and Quercetin-3-O-rhamnosyl-glucoside (3.68 mg/g, 3.22 mg/g, 2.87 mg/g and 2.56 mg/g, respectively). trans-Resveratrol-3-O-glucoside, epicatechin (40.62 mg/g) and proanthocyanidin di- and –trimers (19.90 mg/g – 31.42 mg/g) also were present in the tea. ABTS cation decolorization assay revealed 1.248 mM UAE activity and the percent of DPPH radical scavenging was 14.25%, corresponding to 39.07 μM Trolox equivalents.
Phenolic compounds in Brassica vegetables Cartea, María Elena; Francisco, Marta; Soengas, Pilar ...
Molecules,
12/2010, Letnik:
16, Številka:
1
Journal Article, Book Review
Recenzirano
Odprti dostop
Phenolic compounds are a large group of phytochemicals widespread in the plant kingdom. Depending on their structure they can be classified into simple phenols, phenolic acids, hydroxycinnamic acid ...derivatives and flavonoids. Phenolic compounds have received considerable attention for being potentially protective factors against cancer and heart diseases, in part because of their potent antioxidative properties and their ubiquity in a wide range of commonly consumed foods of plant origin. The Brassicaceae family includes a wide range of horticultural crops, some of them with economic significance and extensively used in the diet throughout the world. The phenolic composition of Brassica vegetables has been recently investigated and, nowadays, the profile of different Brassica species is well established. Here, we review the significance of phenolic compounds as a source of beneficial compounds for human health and the influence of environmental conditions and processing mechanisms on the phenolic composition of Brassica vegetables.
•Caffeic, rosmarinic and salvianolic acids were identified in Salvia hispanica L.•Ferulic acid was identified in hydrolyzed extracts of the Salvia hispanica L.•Danshensu, caffeic, rosmarinic and ...ferulic acids showed electrochemical activity.•The total phenolic content from chia seeds and fiber flour extracts were similar.
The consumption of chia seeds products has increased recently and it has been suggested that the inclusion of this functional food in a daily human diet could contribute to improve consumers’ health. However, a better knowledge about the composition of these products is mandatory. In this work, the phenolic compounds from commercial samples of chia seed, fiber flour and oil were extracted using an ultrasound-assisted methodology and were separated and identified by high-performance liquid chromatography coupled to a mass spectrometer. Methanol:water extracts were prepared and submitted to an acidic hydrolysis. Crude and hydrolyzed extracts were analyzed and phenolic compounds found were mainly caffeic acid and danshensu and its derivatives, such as rosmarinic and salvianolic acids. TPC was higher in the hydrolyzed extracts. These results supply new information about the main phenolic compounds presents in chia, which are important dietary sources of natural antioxidants for prevention of diseases caused by oxidative stress.
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