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  • 1
    Online Resource
    Online Resource
    Glucose biosensor using fluorescence quenching with chitosan‐modified graphene oxide
    Institution of Engineering and Technology (IET) ; 2019
    In:  Micro & Nano Letters Vol. 14, No. 3 ( 2019-03), p. 344-348
    Details
    In: Micro & Nano Letters, Institution of Engineering and Technology (IET), Vol. 14, No. 3 ( 2019-03), p. 344-348
    Type of Medium: Online Resource
    ISSN: 1750-0443 , 1750-0443
    URL: Issue
    URL: Article
    DOI: 10.1049/mna2.v14.3
    DOI: 10.1049/mnl.2018.5269
    Language: English
    Publisher: Institution of Engineering and Technology (IET)
    Publication Date: 2019
    detail.hit.zdb_id: 2378130-0
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  • 2
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    Synthesis of aminopyridinium‐grafted starch derivatives and evaluation of their antioxidant property
    Wiley ; 2017
    In:  Starch - Stärke Vol. 69, No. 7-8 ( 2017-07)
    Details
    In: Starch - Stärke, Wiley, Vol. 69, No. 7-8 ( 2017-07)
    Abstract: In order to improve the bioactivity of starch, novel starch derivatives were developed including 2‐(2‐aminopyridinium)acetyl starch (2APASC), 2‐(3‐aminopyridinium)acetyl starch (3APASC), 2‐(4‐aminopyridinium)acetyl starch (4APASC), 2‐(2,3‐diaminopyridinium)acetyl starch (2,3DAPASC), 2‐(2,6‐diaminopyridinium)acetyl starch (2,6DAPASC), and 2‐(3,4‐diaminopyridinium)acetyl starch (3,4DAPASC). The in vitro antioxidant capacities against hydroxyl‐radical, DPPH‐radical, and superoxide‐radical for all synthesized starch derivatives were evaluated using free radicals scavenging assays. The results showed that the scavenging effect of starch derivatives bearing aminopyridinium groups was better than starch. Especially, 2,3DAPASC and 2,6DAPASC could scavenge hydroxyl‐radicals completely at 0.4 mg/mL. Moreover, the antioxidant property of synthesized starch derivatives was affected by the different positions and the number of amino groups on pyridinium rings. Because the aminopyridinium acetyl starch derivatives could be synthesized conveniently and also possessed significantly strong antioxidant activity, this synthetic strategy might provide an effective tool to broaden further utilization of starch.
    Type of Medium: Online Resource
    ISSN: 0038-9056 , 1521-379X
    URL: Issue
    URL: Article
    DOI: 10.1002/star.v69.7-8
    DOI: 10.1002/star.201600259
    Language: English
    Publisher: Wiley
    Publication Date: 2017
    detail.hit.zdb_id: 1481133-9
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  • 3
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    Online Resource
    Synthesis, Characterization, and the Antifungal Property of Aminoethyl Chitosan Quaternary Ammonium Salts
    Wiley ; 2018
    In:  Starch - Stärke Vol. 70, No. 5-6 ( 2018-05)
    Details
    In: Starch - Stärke, Wiley, Vol. 70, No. 5-6 ( 2018-05)
    Abstract: Chemical modification of chitosan is one of effective methods to improve the biological activity of chitosan. In this paper, aminoethyl chitosan quaternary ammonium salts, including N ‐trimetyl quaternary ammonium salt chitosan (TMC), 6‐O‐(aminoethyl)‐2‐trimethyl quaternary ammonium chitosan derivative (ONC), and 6‐ N ‐(aminoethyl)‐2‐trimethyl quaternary ammonium chitosan derivative (NNC), are successfully designed, synthesized, and characterized by FT‐IR, 1 H NMR, and elemental analyses. Moreover, three kinds of antifungal activities, including B. cinerea Pers ., Gibberella zea , and P. asparagi , are all tested by hyphal measurement in vitro. The results show that all chitosan derivatives have better antifungal activities than chitosan. And the antifungal activity decrease in the order: NNC 〉 ONC  〉 TMC 〉 chitosan at 1.0 mg mL −1 . Furthermore, the inhibitory indices of NNC and ONC against three kinds of phytopathogens are higher than 75% at 1.0 mg mL −1 . Especially, the inhibitory index of NNC against B. cinerea Pers . attain even 90% at 1.0 mg mL −1 . These data demonstrate that the aminated chitoan derivative could remarkably improve the antifungal activity of chitosan. On the one hand, the higher positive charge would interact with the anionic components to damage the cell wall. On the other hand, based on the “permeability” point, the aminoethyl as lipophilic group might pass the oil film into the cell.
    Type of Medium: Online Resource
    ISSN: 0038-9056 , 1521-379X
    URL: Issue
    URL: Article
    DOI: 10.1002/star.v70.5-6
    DOI: 10.1002/star.201700266
    Language: English
    Publisher: Wiley
    Publication Date: 2018
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  • 4
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    Synthesis and Characterization of Inulin Derivatives Bearing Urea Groups with Promising Antifungal Activity
    Wiley ; 2019
    In:  Starch - Stärke Vol. 71, No. 1-2 ( 2019-01)
    Details
    In: Starch - Stärke, Wiley, Vol. 71, No. 1-2 ( 2019-01)
    Abstract: The toxicity concerns associated with chemical fungicides currently on the market have resulted in an increased demand for alternative ecofriendly fungicides. As a biodegradable and biocompatible dietary fiber, inulin shows potential as such a compound, given its lack of toxicity. In the current study, seven novel inulin derivatives with promising antifungal activity (BUCAIL, 2CBUCAIL, 3CBUCAIL, 4CBUCAIL, 3,4CBUCAIL, 2FBUCAIL, and 2BBUCAIL) are synthesized via condensation reactions of chloroacetyl inulin (CAIL) with urea groups bearing 4‐amino‐pyridine. Their structures are confirmed using FT‐IR, 1 H NMR, 13 C NMR, and elemental analysis. Their antifungal activity against three kinds of phytopathogen ( Fusarium oxysporum f. sp. niveum, Phomopsis asparagus , and Fusarium oxysporum f. sp. cucumebrium Owen) is evaluated using the mycelial growth rate in vitro at concentrations of 0.10, 0.25, 0.50, 0.75, and 1.0 mg mL −1 . Results reveal that all seven inulin derivatives show improved antifungal properties compared with unmodified inulin, and two obvious inhibition rules are found: 3,4CBUCAIL  〉  4CBUCAIL  〉  3CBUCAIL  〉  2CBUCAIL  〉  BUCAIL  〉  CAIL  〉  inulin and 2FBUCAIL  〉  2CBUCAIL  〉  2BBUCAIL  〉  BUCAIL  〉  CAIL  〉  inulin. Thus, the introduction of urea groups into inulin derivatives could be key to increasing the antifungal activity of such compounds.
    Type of Medium: Online Resource
    ISSN: 0038-9056 , 1521-379X
    URL: Issue
    URL: Article
    DOI: 10.1002/star.v71.1-2
    DOI: 10.1002/star.201800058
    Language: English
    Publisher: Wiley
    Publication Date: 2019
    detail.hit.zdb_id: 1481133-9
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  • 5
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    Preparation and Characterization of Chitosan Derivatives Bearing Imidazole Ring with Antioxidant, Antibacterial, and Antifungal Activities
    Wiley ; 2023
    In:  Starch - Stärke Vol. 75, No. 3-4 ( 2023-03)
    Details
    In: Starch - Stärke, Wiley, Vol. 75, No. 3-4 ( 2023-03)
    Abstract: In this study, three series of chitosan derivatives bearing imidazole rings, including the Schiff‐bases of chitosan, N ‐substituted chitosan, and quaternized chitosan are designed and synthesized. The structures of these chitosan derivatives are verified by FT‐IR and 1 H NMR, and their antioxidant, antibacterial, and antifungal activities are tested. The Schiff‐bases of chitosan and N ‐substituted chitosan have similar biological properties compared with chitosan. Derivatives 2IMTMC, 4IMTMC, MIMTMC, and BIMTMC exhibit significant antioxidant ability and antifungal activity, especially derivative BIMTMC. All the quaternized chitosan remarkably inhibits Escherichia coli , Staphylococcus aureus , and Vibrio harvey , especially derivative BIMTMC, whose minimum inhibitory concentration values are 0.03125, 0.0625, and 0.03125 mg mL −1 , respectively. The results indicated that quaternized chitosan are synergistic with imidazole groups and have the better antioxidant, antifungal, and antibacterial properties than chitosan, which can be used as drug materials for antioxididant and antimicrobial purposes.
    Type of Medium: Online Resource
    ISSN: 0038-9056 , 1521-379X
    URL: Issue
    URL: Article
    DOI: 10.1002/star.v75.3-4
    DOI: 10.1002/star.202200204
    Language: English
    Publisher: Wiley
    Publication Date: 2023
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  • 6
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    The Antioxidant and Antibacterial Activities of the Pyridine‐4‐Aldehyde Schiff Bases Grafted Chloracetyl Chitosan Oligosaccharide Derivatives
    Wiley ; 2023
    In:  Starch - Stärke Vol. 75, No. 1-2 ( 2023-01)
    Details
    In: Starch - Stärke, Wiley, Vol. 75, No. 1-2 ( 2023-01)
    Abstract: As a reactive intermediate, chloracetyl chitosan oligosaccharide (CACS) can be nucleophilic substituted by some bioactive groups to give novel derivatives of chitosan oligosaccharide (COS). The Schiff bases of pyridine‐4‐aldehyde are grafted onto CACS to give four COS derivatives in this paper. Specific structural characterization is implemented by fourier‐transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). The degree of substitution (DS) of COS derivatives is quantitatively calculated by ratio of hydrogen proton integral. Their antioxidant property is evaluated using free radical scavenging assay towards 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and superoxide anion radicals, and the antibacterial activity against Staphylococcus aureus ( S. aureus ) and Escherichia coli ( E. coli ) is also investigated. The results revealed that the pyridine‐4‐aldehyde Schiff bases grafted chloracetyl chitosan oligosaccharide derivatives showed better antioxidant activity as well as antibacterial activity than COS and CACS, which may be related to the positive charge of these derivatives. Among all final products, derivative BPCACS with the highest DS has the best bioactivity with scavenging rate of 91.49% for the DPPH assay and inhibition diameter of 39.25 mm for S. aureus inhibitory assay, respectively. These results indicated that COS derivatives with enhanced biological activities could serve as potential biomaterial for antioxidant and antibacterial applications.
    Type of Medium: Online Resource
    ISSN: 0038-9056 , 1521-379X
    URL: Issue
    URL: Article
    DOI: 10.1002/star.v75.1-2
    DOI: 10.1002/star.202100268
    Language: English
    Publisher: Wiley
    Publication Date: 2023
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  • 7
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    Synthesis, Characterization, and the Antioxidant Activity of Carboxymethyl Chitosan Derivatives Containing Thiourea Salts
    MDPI AG ; 2019
    In:  Polymers Vol. 11, No. 11 ( 2019-11-04), p. 1810-
    Details
    In: Polymers, MDPI AG, Vol. 11, No. 11 ( 2019-11-04), p. 1810-
    Abstract: A new class of chitosan derivatives possessing thiourea salts were synthesized to improve the solubility and the antioxidant activity of chitosan. Firstly, chitosan was modified to carboxymethyl chitosan, combining carboxymethyl chitosan with thiourea salts that have different structures to form new chitosan derivatives. The chitosan and chitosan derivatives were characterized by FT-IR, 13C NMR, TGA, and elemental analyses. The new peaks of thiourea salts could be clearly observed at about 1240 cm–1 in the IR spectra, and the peak of C=S was clearly observed at around 180 ppm in the 13C NMR. IR spectra and 13C NMR of the structural units of these polymers validated the chitosan derivatives possessing thiourea salts were successfully synthesized. Their antioxidant properties were tested, including DPPH-radical scavenging ability, superoxide-radical scavenging ability, and hydroxyl-radical scavenging ability. Our results suggested the increase of thiourea salt groups in chitosan derivatives promotes the scavenging effect. The scavenging activity of 4TMCMCS, TMCMCS. 4,4DCMCS, and 4ACMCS against DPPH-radical and superoxide-radical were more than 90% at 1.6 mg/mL, respectively. In the cytotoxicity assay, no cytotoxicity was observed for the L929 cells with chitosan and its derivatives at all testing concentrations. These results demonstrated that the combination of chitosan and thiourea salt groups improved the antioxidant activity of chitosan, and the antioxidants or free radical scavengers based on natural polymers and thiourea salts showed potential applications.
    Type of Medium: Online Resource
    ISSN: 2073-4360
    URL: Article
    DOI: 10.3390/polym11111810
    Language: English
    Publisher: MDPI AG
    Publication Date: 2019
    detail.hit.zdb_id: 2527146-5
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  • 8
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    Online Resource
    Preparation, Anticoagulant and Antioxidant Properties of Glucosamine-Heparin Salt
    MDPI AG ; 2022
    In:  Marine Drugs Vol. 20, No. 10 ( 2022-10-18), p. 646-
    Details
    In: Marine Drugs, MDPI AG, Vol. 20, No. 10 ( 2022-10-18), p. 646-
    Abstract: Excessive inorganic ions in vivo may lead to electrolyte disorders and induce damage to the human body. Therefore, preparation of enhanced bioactivity compounds, composed of activated organic cations and organic anions, is of great interest among researchers. In this work, glucosamine-heparin salt (GHS) was primarily synthesized with positively charged glucosamine hydrochloride (GAH) and negatively charged heparin sodium (Heps) by ion exchange method. Then, the detailed structural information of the GHS was characterized by FTIR, 1H NMR spectroscopy and ICP-MS. In addition, its anticoagulant potency and antioxidant properties were evaluated, respectively. The results demonstrated that GHS salt achieved enhanced antioxidant activities, including 98.78% of O2•− radical scavenging activity, 91.23% of •OH radical scavenging rate and 66.49% of DPPH radical scavenging capacity at 1.6 mg/mL, severally. Meanwhile, anticoagulant potency (ATTP) of GHS strengthened from 153.10 ± 17.14 to 180.03 ± 6.02 at 0.75 μmol/L. Thus, introducing cationic glucosamine residues into GHS could improve its anticoagulant activity. The findings suggest that GHS product with a small amount of inorganic ions can greatly abate the prime cost of antioxidants and anticoagulants, and has significant economic benefits and practical significance.
    Type of Medium: Online Resource
    ISSN: 1660-3397
    URL: Article
    DOI: 10.3390/md20100646
    Language: English
    Publisher: MDPI AG
    Publication Date: 2022
    detail.hit.zdb_id: 2175190-0
    SSG: 15,3
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  • 9
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    Synthesis and Characterization of N,N,N-trimethyl-O-(ureidopyridinium)acetyl Chitosan Derivatives with Antioxidant and Antifungal Activities
    MDPI AG ; 2020
    In:  Marine Drugs Vol. 18, No. 3 ( 2020-03-16), p. 163-
    Details
    In: Marine Drugs, MDPI AG, Vol. 18, No. 3 ( 2020-03-16), p. 163-
    Abstract: Chitosan is an active biopolymer, and the combination of it with other active groups can be a valuable method to improve the potential application of the resultant derivatives in food, cosmetics, packaging materials, and other industries. In this paper, a series of N,N,N-trimethyl-O-(ureidopyridinium)acetyl chitosan derivatives were synthesized. The combination of chitosan with ureidopyridinium group and quaternary ammonium group made it achieve developed water solubility and biological properties. The structures of chitosan and chitosan derivatives were confirmed by FTIR, 1H NMR spectra, and elemental analysis. The prepared chitosan derivatives were evaluated for antioxidant property by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability, hydroxyl radical scavenging ability, and superoxide radical scavenging ability. The results revealed that the synthesized chitosan derivatives exhibited improved antioxidant activity compared with chitosan. The chitosan derivatives were also investigated for antifungal activity against Phomopsis asparagus as well as Botrytis cinerea, and they showed a significant inhibitory effect on the selected phytopathogen. Meanwhile, CCK-8 assay was used to test the cytotoxicity of chitosan derivatives, and the results showed that most derivatives had low toxicity. These data suggested to develop analogs of chitosan derivatives containing ureidopyridinium group and quaternary ammonium group, which will provide a new kind of promising biomaterials having decreased cytotoxicity as well as excellent antioxidant and antimicrobial activity.
    Type of Medium: Online Resource
    ISSN: 1660-3397
    URL: Article
    DOI: 10.3390/md18030163
    Language: English
    Publisher: MDPI AG
    Publication Date: 2020
    detail.hit.zdb_id: 2175190-0
    SSG: 15,3
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  • 10
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    Synthesis, characterization, and antioxidant activity of carboxymethyl chitosan derivatives containing sulfonium salt
    Springer Science and Business Media LLC ; 2022
    In:  Journal of Oceanology and Limnology Vol. 40, No. 1 ( 2022-01), p. 284-295
    Details
    In: Journal of Oceanology and Limnology, Springer Science and Business Media LLC, Vol. 40, No. 1 ( 2022-01), p. 284-295
    Type of Medium: Online Resource
    ISSN: 2096-5508 , 2523-3521
    URL: Article
    DOI: 10.1007/s00343-021-0352-2
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2022
    detail.hit.zdb_id: 2931064-7
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