Quercetin as a precursor in the synthesis of analogues of fulvic acids and their antibacterial properties

A simple, fast and effective method for producing synthetic substances with properties similar to natural humic substances has been proposed. The synthesis method is based on the oxidation of quercetin by molecular oxygen in an alkaline medium, followed by conversion to the acid form by passing through a cation exchange column. Study of elemental and functional compositions, spectral properties (UV/Vis and IR range) and redox characteristics allowed qualifying the resulting product as a synthetic fulvic acid. The enhanced antibacterial properties of the obtained synthetic product were established. The minimum concentration of inhibition of synthetic fulvic acid derived from quercetin is 25 g mL–1, which is in 100 times less than for natural humic substances.

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Development of methods for the separation and characterization of natural organic matter in dam water

10.51415/10321/1182 ◽

2014 ◽

Author(s):

◽

Pinkie Sobantu

Keyword(s):

Molecular Weight ◽

Humic Acid ◽

Fulvic Acid ◽

Humic Substances ◽

Water Samples ◽

Fulvic Acids ◽

Hydroxyl Groups ◽

Humic And Fulvic Acids ◽

Vaal Dam

This project arose out the need for a simple method to analyse NOM on a routine basis. Water samples were obtained from the Vaal dam, which is one of the dams used by a hydroelectric power station. Analysis was preceded by separation of NOM into the humic and non-humic portions. The humic portion was separated into two fractions by employing a non-ionic resin (DAX-8) to separate humic acid from fulvic acid. High performance size exclusion chromatography (HPSEC), equipped with an Ultraviolet( UV) detector and an Evaporative Light Scattering (ELS) detector connected in series, was used to obtain molecular weight distribution information and the concentration levels of the two acids. Mixed standards of polyethylene oxide/glycol were employed to calibrate the selected column. Suwanee River humic acid standard was used as a certified reference material. The molecular weight distributions (MWDs) of the isolated fractions of humic and fulvic acids were determined with ELSD detection as weight-average (Mw), number-average (Mn) and polydispersity (ρ) of individual NOM fractions. The Mw/Mn ratio was found to be less than 1.5 in all the fractions, indicating that they have a low and narrow size fraction. An increase in Mn and Mw values, with increasing wavelength for all three humic substances (HS) examined was observed. The HS, isolated from the dam water, was found to be about the same molecular weight as the International Humic Acid Standard (IIHSS). For the fulvic acid standard, the molecular weight was estimated to be around 7500 Da. Characterization of NOM was done to assist in the identification of the species present in the water. FTIR-ATR was used to as a characterization tool to identify the functional groups in the structure of the humic and fulvic acid respectively present in the Vaal Dam. Analysis of the infrared (IR) spectra indicated that the humic acids of the Vaal dam have phenolic hydroxyl groups, hydroxyl groups, conjugated double bond of aromatic family (C=C), and free carboxyl groups. The isolation method has proved to be applicable and reliable for dam water samples and showed to successfully separate the humic substances from water and further separate the humic substances into its hydrophobic acids, namely, humic and fulvic acids. It can be concluded that the Eskom Vaal dam composes of humic substance which shows that the technique alone gives a very good indication of the characteristics of water. The HPSEC method used, equipped with UV and ELSD was able to identify the molecular weight range of NOM present in source water as it confirmed that the Eskom Vaal dam contains humic substances as humic acid and fulvic acid and these pose a health concern as they can form disinfectant byproducts in the course of water treatment with chemicals. FTIR characterization was successful as important functional groups were clearly assigned. Lastly, the use of the TOC and DOC values to calculate SUVA was also a good tool to indicate the organic content in water. It is recommended to use larger amounts of water must be processed to obtain useful quantities of the humic and fulvic acid fractions.

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The fate of estrogenic compounds in the aquatic environment: sorption onto organic colloids

Water Science & Technology ◽

10.2166/wst.2003.0497 ◽

2003 ◽

Vol 47 (9) ◽

pp. 77-84 ◽

Cited By ~ 26

Author(s):

H. Yamamoto ◽

H.M. Liljestrand

Keyword(s):

Humic Acid ◽

Fulvic Acid ◽

Humic Substances ◽

Alginic Acid ◽

Fulvic Acids ◽

Estrogenic Compounds ◽

Treatment Processes ◽

Suwannee River ◽

Suwannee River Fulvic Acid ◽

17Β Estradiol

In this study, sorption of some estrogens and estrogenic compounds onto several organic colloids was examined using fluorescence quenching techniques. Selected organic colloids included humic substances of several sources, Aldrich humic acid (AHA), Suwannee River humic acid (SRHA), Suwannee River fulvic acid (SRFA), and Nordic fulvic acid (NFA). Polysaccharides, alginic acid (AA) and dextran (Dex), and tannic acid (TA) were also selected. 17β-estradiol (E2), 17α-ethynylestradiol (EES), and estriol (E3) were selected as estrogens. Nonylphenol (NP), octylphenol (OP), and dibutylphthalate (DBP) were selected as estrogenic compounds. For most of the selected compounds, the sorption coefficients were in the order of TA > humic acids (SRHA or AHA) > fulvic acids (NFA or SRFA) > AA. The smallest or no significant sorption onto dextran was found for selected estrogens and estrogenic compounds. Comparing those compounds, neither a significant trend nor linear correlation with Log Kow was found. The resulting sorption coefficients for humic substances and TA suggested approximately 15 to 50% of the estrogens and estrogenic compounds were bound in typical natural water of 5 mgTOC/L and significant effects on the removal of them by water treatment processes, toxicity, or bioavailability were suggested.

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Accumulation of humic substances in an Oxisol fertilized with pig slurry for 15 years

Revista Brasileira de Engenharia Agrícola e Ambiental ◽

10.1590/1807-1929/agriambi.v25n2p109-115 ◽

2021 ◽

Vol 25 (2) ◽

pp. 109-115

Author(s):

Wagner Sacomori ◽

Paulo C. Cassol ◽

Maria S. H. Mafra ◽

Luiza F. Erdemann ◽

Jaime A. de Almeida

Keyword(s):

Humic Acid ◽

Organic Carbon ◽

Fulvic Acid ◽

Humic Substances ◽

Soil Layer ◽

Mineral Fertilizer ◽

Soil Surface ◽

Fulvic Acids ◽

Pig Slurry ◽

Continuous Application

ABSTRACT The growth of swine production in Brazil has increased the amount of production and use of pig slurry (PS) as soil fertilizer. This product provides nutrients to plants, and a continuous application of this residue usually increases total soil organic carbon (SOC) content. The objective of this study was to determine the SOC content and its distribution into humic substance fractions (humic acids, fulvic acids, and humin) in an Oxisol annually fertilized with PS for 15 years. The experiment was implemented in 2001 with a maize and oat crop rotation under no-tillage system in Campos Novos, SC, Brazil. The treatments used were: PS at rates of 0 (Control), 25, 50, 100, and 200 m3 ha-1 year-1, mineral fertilizer, and PS combined with mineral fertilizer, applied on the soil surface once a year. The 0-2.5, 2.5-5, 5-10, 10-20, 20-40, and 40-60 cm soil layers were evaluated for SOC content in the fractions humic acid, fulvic acid, and humin, and E4/E6 ratio of humic substances. Increases in PS rates up to 100 m3 ha-1 increased the SOC content in the 5-10 cm soil layer; however, decreased the proportion of the soil fulvic acid and humic acid fractions, favoring the accumulation of organic carbon in the humin fraction. The E4/E6 ratio was higher when using the soil mineral fertilizer than that found in treatments with PS.

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Humic substances and their effects on the micropropagation of banana

Research Society and Development ◽

10.33448/rsd-v10i2.12297 ◽

2021 ◽

Vol 10 (2) ◽

pp. e20510212297

Author(s):

Victor Hugo Teixeira Buttrós ◽

Maysa Mathias Alves Pereira ◽

Adalvan Daniel Martins ◽

Filipe Almendagna Rodrigues ◽

Moacir Pasqual ◽

...

Keyword(s):

Fulvic Acid ◽

Humic Substances ◽

Agricultural Production ◽

Production Systems ◽

Fulvic Acids ◽

Social Contexts ◽

Environmental Preservation ◽

Vitro Development ◽

Agricultural Production Systems

The growing concern to promote sustainable agriculture, seeking environmental preservation and, at the same time, increased productivity resulted in the search for technologies for the implementation of agricultural production systems, with ecological approaches and responsible use of natural resources, in the economic, political and social contexts in each region. One of the potential alternatives to achieve these results would be the use of humic substances, considering their direct and indirect mechanisms aimed at increasing agricultural production. Thus, the objective of this work was to evaluate the bioactivity of humic and fulvic acids, as well as to promote improvements in the phytotechnical attributes of banana cv. Prata-Anã micropropagated. The treatments consisted of five doses of humic acid and fulvic acid (2; 5; 10; 20 and 40 mg L-1) and a control without humic substances. Higher values for the length of the aerial part and the larger root were obtained with the use of 40 mg L-1 fulvic acid. The results prove the ability of fulvic acid to improve the in vitro development of banana explants.

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Characterization of Soil Organic Matter Individual Fractions (Fulvic Acids, Humic Acids, and Humins) by Spectroscopic and Electrochemical Techniques in Agricultural Soils

Agronomy ◽

10.3390/agronomy11061067 ◽

2021 ◽

Vol 11 (6) ◽

pp. 1067

Author(s):

Aleksandra Ukalska-Jaruga ◽

Romualda Bejger ◽

Guillaume Debaene ◽

Bożena Smreczak

Keyword(s):

Molecular Weight ◽

Organic Matter ◽

Soil Organic Matter ◽

Humic Substances ◽

Humic Acids ◽

Agricultural Soils ◽

Fulvic Acids ◽

Sorption Properties ◽

Aliphatic Chains

The objective of this paper was to investigate the molecular characterization of soil organic matter fractions (humic substances (HS): fulvic acids-FAs, humic acids-HAs, and humins-HNs), which are the most reactive soil components. A wide spectrum of spectroscopic (UV–VIS and VIS–nearIR), as well as electrochemical (zeta potential, particle size diameter, and polydispersity index), methods were applied to find the relevant differences in the behavior, formation, composition, and sorption properties of HS fractions derived from various soils. Soil material (n = 30) used for the study were sampled from the surface layer (0–30 cm) of agricultural soils. FAs and HAs were isolated by sequential extraction in alkaline and acidic solutions, according to the International Humic Substances Society method, while HNs was determined in the soil residue (after FAs and HAs extraction) by mineral fraction digestion using a 0.1M HCL/0.3M HF mixture and DMSO. Our study showed that significant differences in the molecular structures of FAs, Has, and HNs occurred. Optical analysis confirmed the lower molecular weight of FAs with high amount of lignin-like compounds and the higher weighted aliphatic–aromatic structure of HAs. The HNs were characterized by a very pronounced and strong condensed structure associated with the highest molecular weight. HAs and HNs molecules exhibited an abundance of acidic, phenolic, and amine functional groups at the aromatic ring and aliphatic chains, while FAs mainly showed the presence of methyl, methylene, ethenyl, and carboxyl reactive groups. HS was characterized by high polydispersity related with their structure. FAs were characterized by ellipsoidal shape as being associated to the long aliphatic chains, while HAs and HNs revealed a smaller particle diameter and a more spherical shape caused by the higher intermolecular forcing between the particles. The observed trends directly indicate that individual HS fractions differ in behavior, formation, composition, and sorption properties, which reflects their binding potential to other molecules depending on soil properties resulting from their type. The determined properties of individual HS fractions are presented as averaged characteristics over the examined soils with different physico-chemical properties.

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Au–ZnO Conjugated Black Phosphorus as a Near-Infrared Light-Triggering and Recurrence-Suppressing Nanoantibiotic Platform against Staphylococcus aureus

Pharmaceutics ◽

10.3390/pharmaceutics13010052 ◽

2021 ◽

Vol 13 (1) ◽

pp. 52

Author(s):

Atanu Naskar ◽

Sohee Lee ◽

Kwang-sun Kim

Keyword(s):

Staphylococcus Aureus ◽

Bacterial Infections ◽

Near Infrared ◽

Au Nanoparticles ◽

Synthesis Method ◽

Antibacterial Properties ◽

Black Phosphorus ◽

Infrared Light ◽

Resistant Bacteria ◽

Near Infrared Light

Antibiotic therapy is the gold standard for bacterial infections treatment. However, the rapid increase in multidrug-resistant (MDR) bacterial infections and its recent use for secondary bacterial infections in many COVID-19 patients has considerably weakened its treatment efficacy. These shortcomings motivated researchers to develop new antibacterial materials, such as nanoparticle-based antibacterial platform with the ability to increase the chances of killing MDR strains and prevent their drug resistance. Herein, we report a new black phosphorus (BP)-based non-damaging near-infrared light-responsive platform conjugated with ZnO and Au nanoparticles as a synergistic antibacterial agent against Staphylococcus aureus species. First, BP nanosheets containing Au nanoparticles were assembled in situ with the ZnO nanoparticles prepared by a low-temperature solution synthesis method. Subsequently, the antibacterial activities of the resulting Au–ZnO–BP nanocomposite against the non-resistant, methicillin-resistant, and erythromycin-resistant S. aureus species were determined, after its photothermal efficacy was assessed. The synthesized nanocomposite exhibited excellent anti-S. aureus activity and good photothermal characteristics. The non-resistant S. aureus species did not produce drug-resistant bacteria after the treatment of multiple consecutive passages under the pressure of the proposed nanoantibiotic, but rapidly developed resistance to erythromycin. This work clearly demonstrates the excellent photothermal antibacterial properties of Au–ZnO–BP nanocomposite against the MDR S. aureus species.

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Organic Materials and Their Chemically Extracted Humic and Fulvic Acids as Potential Soil Amendments for Faba Bean Cultivation in Soils with Varying CaCO3 Contents

Horticulturae ◽

10.3390/horticulturae7080205 ◽

2021 ◽

Vol 7 (8) ◽

pp. 205

Author(s):

Ihab M. Farid ◽

Mohamed A. El-Ghozoli ◽

Mohamed H. H. Abbas ◽

Dalia S. El-Atrony ◽

Hassan H. Abbas ◽

...

Keyword(s):

Humic Substances ◽

Faba Bean ◽

Plant Biomass ◽

Nitrogenase Activity ◽

Organic Amendments ◽

Fulvic Acids ◽

Mineral N ◽

Randomized Design ◽

Long Time ◽

Factor C

Organic amendments are important sources of nutrients that release upon organic matter degradation, yet the stability of these organics in arid and semi-arid regions is relatively low. In contrast, humic substances (HS) are resistant to biodegradation and can keep nutrients in the soil available for the plant over a long time. Combinations between humic substances (HS) and mineral-N fertilizers are assumed to retain higher available nutrients in soils than those recorded for the sole application of either mineral or organic applications. We anticipate, however, that humic substances might not be as efficient as the organics from which they were extracted in increasing NP uptake by plants. To test these assumptions, faba bean was planted in a pot experiment under greenhouse conditions following a complete randomized design while considering three factors: two soils (calcareous and non-calcareous, Factor A), two organics (biogas and compost, Factor B) and combinations of the organics and their extracts (HA or FA) together with complementary doses of mineral-N ((NH4)2SO4) to attain a total rate of 50 kg N ha−1 (the recommended dose for faba bean plants) (Factor C). Results indicated that nitrogenase activity increased significantly due to the application of the used organics. In this respect, compost manure caused higher nitrogenase activity than biogas manure did. Humic substances raised NP-availability and the uptake by plants significantly; however, the values of increase were lower than those that occurred due to the compost or biogas manure. Moreover, the sole application of the used organics recorded the highest increases in plant biomass. Significant correlations were also detected between NP-availability, uptake and plant biomass. This means that HS could probably retain nutrients in available forms for long time periods, yet nutrients released continuously but slowly upon decomposition of organics seemed more important for plant nutrition.

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Determination of Organic Compounds, Fulvic Acid, Humic Acid, and Humin in Peat and Sapropel Alkaline Extracts

Molecules ◽

10.3390/molecules26102995 ◽

2021 ◽

Vol 26 (10) ◽

pp. 2995

Author(s):

Laurynas Jarukas ◽

Liudas Ivanauskas ◽

Giedre Kasparaviciene ◽

Juste Baranauskaite ◽

Mindaugas Marksa ◽

...

Keyword(s):

Humic Acid ◽

Fulvic Acid ◽

Humic Substances ◽

Organic Compounds ◽

Chemical Constituents ◽

Acid Amide ◽

Extraction Methods ◽

Ultrasound Extraction ◽

Different Origins

Black, brown, and light peat and sapropel were analyzed as natural sources of organic and humic substances. These specific substances are applicable in industry, agriculture, the environment, and biomedicine with well-known and novel approaches. Analysis of the organic compounds fulvic acid, humic acid, and humin in different peat and sapropel extracts from Lithuania was performed in this study. The dominant organic compound was bis(tert-butyldimethylsilyl) carbonate, which varied from 6.90% to 25.68% in peat extracts. The highest mass fraction of malonic acid amide was in the sapropel extract; it varied from 12.44% to 26.84%. Significant amounts of acetohydroxamic, lactic, and glycolic acid derivatives were identified in peat and sapropel extracts. Comparing the two extraction methods, it was concluded that active maceration was more efficient than ultrasound extraction in yielding higher amounts of organic compounds. The highest amounts of fulvic acid (1%) and humic acid and humin (15.3%) were determined in pure brown peat samples. This research on humic substances is useful to characterize the peat of different origins, to develop possible aspects of standardization, and to describe potential of the chemical constituents.

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Bioavailability of a nonylphenol isomer in dependence on the association to dissolved humic substances

Water Science & Technology ◽

10.2166/wst.2004.0338 ◽

2004 ◽

Vol 50 (5) ◽

pp. 277-283 ◽

Cited By ~ 16

Author(s):

R. Vinken ◽

A. Höllrigl-Rosta ◽

B. Schmidt ◽

A. Schäffer ◽

P.F.-X. Corvini

Keyword(s):

Humic Acid ◽

Carbon Source ◽

Humic Substances ◽

Organic Compounds ◽

Sole Carbon Source ◽

Equilibrium Dialysis ◽

Fulvic Acids ◽

Degrading Bacterium ◽

Bacterium Strain ◽

Dissolved Humic Substances

Humic substances are important environmental components since they represent a very large part of organic compounds on earth. According to many reports, dissolved humic substances are a determinant parameter for the bioavailability of xenobiotic compounds. For the present bioavailability studies, two kinds of dissolved humic substances, a commercially available humic acid and fulvic acids isolated from peat were used. As the relevant xenobiotic, a defined branched nonylphenol isomer, 4(3′,5′-dimethyl-3′-heptyl)-phenol (p353NP) was synthesised according to Friedel-Crafts alkylation. Equilibrium dialysis studies were implemented in order to investigate the association between 14C-labelled p353NP and dissolved humic substances. The biodegradability in the presence of dissolved humic substances was examined in experiments with the nonylphenol degrading bacterium strain Sphingomonas TTNP3 and with p353NP as sole carbon source. The results showed that p353NP-humic acid associates were formed in high amounts, whereas no adducts with fulvic acids occurred. In the degradation studies with Sphingomonas TTNP3, no effects of dissolved humic substances on the bioavailability of p353NP could be observed. It was assumed that the association between nonylphenol and humic acids occurs rapidly and is reversible. Thus, the formation of "labile" complexes did not influence biodegradation rates, which were quite low.

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