Properties of Functional Films Based on Chitosan Derivative with Gallic Acid

Conjugates of chitosan (molecular weight 28 and 830 kDa) with gallic acid were synthesized by a reaction initiated by a free radical. The conjugates contained 106 and 119 mg of polyphenol per g of polymer. Thin films were obtained from solutions of synthesized chitosan derivatives, and their physico-chemical characteristics (thickness of 0.058–0.076 mm and moisture content of 7.92–9.44%), as well as the antioxidant (inhibiting activity with respect to 2,2-diphenyl-1-picrylhydrazyl) and antimicrobial properties, were studied in relation to Staphylococcus epidermidis and Escherichia coli.     

Synthesis,Antimicrobial and Antioxidant Activity of Pyrazole Based Sulfonamide Derivatives

A series of new sulfonamides have been synthesized from Ampyrone with different benzene sulfonyl chlorides to yield the N-1,5-dimethyl-3-oxo-2-phenyl-2,3-dihydro-1H-pyrazol-4-yl) benzenesulfonamides (4a–e). All synthesized compounds were characterized on the basis of FTIR, ¹H NMR, and ¹³C NMR, and also by the aid of mass spectral data. Further, all synthesized compounds have studied for their in vitro antimicrobial activities against selected bacterial as well as fungal strains by the agar well diffusion method. Free radical scavenging activity has been investigated by using DPPH method. Among all the synthesized compounds, 4b, 4d, and 4e exhibited significant antimicrobial and antioxidant activities.     

Novel Antimicrobial and Antioxidant Chitosan Derivatives Prepared by Green Grafting with Phenyllactic Acid

In order to develop novel antimicrobial and antioxidant biopolymers for active packaging to improve quality and safety of food products, we for the first time grafted phenyllatic acid (PLA) on chitosan (CS) using a green and facile method. The reaction between PLA and CS was confirmed by UV ? vis and Fourier-transform infrared spectroscopy. The grafting ratio was 5.72%, 9.16% and 11.83%, respectively, at a PLA:CS molar ratio of 1:1, 2:1, and 3:1. The grafting of PLA on CS reduced the thermal decomposition temperature of CS according to differential scanning calorimetry. A greater grafting ratio corresponded to a higher activity of scavenging 2, 2-diphenyl-1-picrylhydrazyl radicals and inhibition to growth of Gram-positive Staphylococcus aureus and Listeria monocytogenes, Gram-negative Escherichia coli and Salmonella enterica, and fungi Saccharomyces cerevisiae and Penicillium expansum (P < 0.05). These novel CS derivatives have potential to reduce oxidation and inhibit spoilage microorganisms to improve food quality and safety.     

The Antiviral Activity of Chitosan (Review)

Data on the inhibitory effect of chitosan on viral infections in animals, plants, and microorganisms are reviewed. The effects of the physicochemical parameters and structure of chitosan on its antiviral activity are analyzed. Possible mechanisms of the inhibitory effect of chitosan on viral infections are discussed.     

Antimicrobial Peptides in Health and Disease (Review)

The review describes the latest data on the role of antimicrobial peptides (AMPs) in health and disease, as well as their structure and mechanisms of action. AMPs mediate protection by both direct lysis of bacteria and also by regulation of inflammation and chemotaxis, thus demonstrating immunomodulatory properties. A large amount of data shows that AMPs play an important role in the pathogenesis of multiple chronic diseases with genetic predisposition, such as atopic dermatitis, rosacea, and scleroderma.     

Mechanical Properties of Collagen Biomimetic Films Formed in the Presence of Calcium,Silica and Chitosan

Using eucollagen solutions from ox hide, we cast collagen films to assess the influence of calcium and silica on the reconstitution of the fibrous structure of collagen. The tensile strength and the breaking elongation of the reconstituted collagen films were measured and analysed. Significant differences were observed between reconstituted collagen films with and without calcium and silica. The breaking elongation of the films obtained in the presence of silica was significantly greater, and the degradation was lower than other films of reconstituted collagen. Collagen and chitosan do not exist together as blends in nature, but the specific properties of each may be used to produce in biomimetic way man-made blends with biomedical applications, that confer unique structural, mechanical （detail） and in vivo properties.     

Effect of Transglutaminase on the Properties of Films Prepared from Chitosan and Gelatin

Applied Biochemistry and Microbiology - The production conditions were optimized, and the characteristics of biodegradable chitosan-gelatin films crosslinked with various microbial...     

Chitosan/Collagen Hydrolysate Based Films Obtained from Hide Trimming Wastes Reinforced with Chitosan Nanoparticles

One of the long-standing problems of the leather manufacturing industry is that tons of solid leather waste generated during production meet environmental standards. Among all these solid wastes, untanned trimming wastes are of primary interest because of their relative collagen content, and therefore, in this research, hide trimming wastes from tanneries were used to prepare biodegradable films. The SDS-PAGE results suggested that obtained collagen hydrolysate (CH) was in its natural molecular form. Chitosan nanoparticles (CSNPs) were synthesized by ionotropic gelation technique with chitosan (CS) and tripolyphosphate anions and used in the preparation of CS/CH/CSNPs films containing different concentrations of CSNPs. The incorporation of CSNPs in CS/CH films has positively improved the films' remarkable physical properties. The DSC result showed that CS/CH films incorporated with CSNPs had higher glass transition and melting temperature. As a result, it was determined that CS/CH/CSNPs nanocomposite films have a high potential in biodegradable film systems.

     

蜜蜂巢脾抗氧化活性与抗菌活性的研究

以意蜂巢脾和中蜂巢脾为研究材料,分别采用水提法和醇提法处理,对获得的4种提取物,以DPPH.法测定自由基清除能力,福林酚法测定总酚含量,琼脂扩散法测定其对金黄色葡萄球菌和大肠杆菌的抑菌半径。结果表明,巢脾提取物具有一定的抗氧化活性和抑菌活性,且含有丰富的酚类化合物。除了对大肠杆菌的抑制作用外,巢脾水提液效果优于巢脾醇提液;除DPPH.清除能力外,意蜂巢脾效果优于中蜂巢脾效果;生物学活性呈现浓度依赖效应。本研究为巢脾在中医药领域的应用提供了一定的解释,并证明了巢脾是一种潜在的天然生物资源。     

Properties,Microstructure and Heat Seal Ability of Bilayer Films Based on Fish Gelatin and Emulsified Gelatin Films

Bilayer films prepared by the lamination of fish gelatin film (GF) and its corresponding emulsified film (EF) with different thickness ratios (7:3, 5:5 and 3:7) were characterized. Bilayer films had the similar tensile strength (TS) to EF (p > 0.05) but showed lower elongation at break (EAB) (p < 0.05). All bilayer films showed the lower water vapor permeability (WVP) but higher oxygen permeability (OP) than GF. Bilayer films had varying ΔE* (total color different), where the highest value was observed in that laminated with higher thickness ratio of EF (p < 0.05). Lower light transmission and higher transparency value were obtained for bilayer films, compared to GF (p < 0.05). Based on scanning electron microscopic (SEM) cross-section micrographs, all bilayer films consisted of two layers. Differential scanning calorimetric (DSC) analysis revealed that the bilayer films had the higher glass transition temperature (T _g) than GF but lower than EF. All bilayer films were heat sealable, however their seal strength and seal efficiency were lower than those of GF (p < 0.05). Therefore, the thickness ratios of GF and EF had a marked effect on the mechanical and barrier properties as well as heat sealing ability of resulting bilayer films.     

Properties and uses of protein hydrolysates (Review)

Properties of protein hydrolysates and possible uses of these substances in research and various branches of industry are considered. The main problem discussed in this paper is the relationship between the degree of protein conversion and characteristics (structural-functional and physicochemical) of hydrolysates.     

Antimicrobial Activity,Stability and Wound Healing Performances of Chitosan Nanoparticles Loaded Recombinant LL37 Antimicrobial Peptide

International Journal of Peptide Research and Therapeutics - Antimicrobial peptides have illustrated potent abilities in the elimination of several pathogens resistant to conventional antimicrobial...     

壳聚糖及其衍生物抗菌性质的研究进展

壳聚糖对多种细菌、真菌具有广谱抗菌的功能,因此它被广泛地应用于广泛地用于口腔疾病、皮肤炎症、伤口感染、胃肠道疾病等各种疾病的治疗。本文综述了壳聚糖及其衍生物对常见的口腔致病菌、皮肤癣菌、伤口感染菌以及胃肠道疾病的致病菌的抗菌作用和壳聚糖及其衍生物的抗菌机理。     

硫脲壳聚糖金属配合物的抗氧化活性研究

通过测定对羟自由基、超氧负离子自由基的清除率和还原能力,研究了壳聚糖、硫脲壳聚糖及5种硫脲壳聚糖金属配合物的抗氧化活性。结果表明:在实验设置的浓度范围内,对羟自由基的清除能力依次为硫脲壳聚糖Cu(Ⅱ)>硫脲壳聚糖Fe(Ⅱ)>硫脲壳聚糖Co(Ⅱ)>硫脲壳聚糖Ni(Ⅱ)>硫脲壳聚糖Zn(Ⅱ),且清除能力随着浓度的增加而增强;对超氧负离子自由基清除能力依次为硫脲壳聚糖Ni(Ⅱ)>硫脲壳聚糖Zn(Ⅱ)>硫脲壳聚糖Co(Ⅱ)>硫脲壳聚糖Cu(Ⅱ)>硫脲壳聚糖Fe(Ⅱ),且清除能力随着浓度的增加而增强;还原能力依次为硫脲壳聚糖Co(Ⅱ)>硫脲壳聚糖Cu(Ⅱ)>硫脲壳聚糖Fe(Ⅱ)>硫脲壳聚糖Ni(Ⅱ)>硫脲壳聚糖Zn(Ⅱ)。     

Regioselective Sequential Modification of Chitosan via Azide-Alkyne Click Reaction: Synthesis,Characterization, and Antimicrobial Activity of Chitosan Derivatives and Nanoparticles

Recently, the attention of researchers has been drawn toward the synthesis of chitosan derivatives and their nanoparticles with enhanced antimicrobial activities. In this study, chitosan derivatives with different azides and alkyne groups were synthesized using click chemistry, and these were further transformed into nanoparticles by using the ionotropic gelation method. A series of chitosan derivatives was successfully synthesized by regioselective modification of chitosan via an azide-alkyne click reaction. The amino moieties of chitosan were protected during derivatization by pthaloylation and subsequently unblocked at the end to restore their functionality. Nanoparticles of synthesized derivatives were fabricated by ionic gelation to form complexes of polyanionic penta-sodium tripolyphosphate (TPP) and cationic chitosan derivatives. Particle size analysis showed that nanoparticle size ranged from 181.03 ± 12.73 nm to 236.50 ± 14.32 nm and had narrow polydispersity index and positive surface charge. The derivatives and corresponding nanoparticles were evaluated in vitro for antibacterial and antifungal activities against three gram-positive and gram-negative bacteria and three fungal strains, respectively. The minimum inhibitory concentration (MIC) of all derivatives ranged from 31.3 to 250 µg/mL for bacteria and 188 to1500 µg/mL for fungi and was lower than that of native chitosan. The nanoparticles with MIC ranging from 1.56 to 25 µg/mLfor bacteria and 94 to 750 µg/mL for fungi exhibited higher activity than the chitosan derivatives. Chitosan O-(1-methylbenzene) triazolyl carbamate and chitosan O-(1-methyl phenyl sulfide) triazolyl carbamate were the most active against the tested bacterial and fungal strains. The hemolytic assay on erythrocytes and cell viability test on two different cell lines (Chinese hamster lung fibroblast cells V79 and Human hepatic cell line WRL68) demonstrated the safety; suggesting that these derivatives could be used in future medical applications. Chitosan derivatives with triazole functionality, synthesized by Huisgen 1,3-dipolar cycloaddition, and their nanoparticles showed significant enhancement in antibacterial and antifungal activities in comparison to those associated with native, non-altered chitosan.     

低聚壳聚糖衍生物的制备及其抗氧化性能

低聚壳聚糖(COS)经化学改性得到N-苯亚甲基壳聚糖(NBCOS)和O-2'-羟丙基三甲基氯化铵壳聚糖(OHCOS),对其结构进行表征.考察了COS及其衍生物对超氧阴离子O2¨、羟基自由基·OH、DPPH自由基的清除活性以及还原能力.结果表明:当浓度为10 mg/mL时,COS和OHCOS对O2¨的清除率分别为89.6%和85.5%,而同样浓度时NBCOS的清除率仅有6.9%;它们清除·OH和DPPH的活性大小顺序为COS>OHCOS>NBCOS,而还原能力大小顺序为COS>NBCOS>OHCOS.     

Antimicrobial,Antioxidant, and Anti-Inflammatory Activities of Essential Oils from Five Selected Herbs

Eucalyptus bridgesiana, Cymbopogon martinii, Thymus vulgaris, Lindernia anagallis, and Pelargonium fragrans are five species of herbs used in Asia. Their essential oils were analyzed by GC-MS, and a total of 36 components were detected. The results of our study indicated that, except for the essential oil of P. fragrans, all of the essential oils demonstrated obvious antimicrobial activity against a broad range of microorganisms. The C. martinii essential oil, which is rich in geraniol, was the most effective antimicrobial additive. All of the essential oils demonstrated antioxidant activities on 2,2-diphenyl-1-picrylhydrazyl radical scavenging assay, β-carotene/linoleic acid assay, and nitric oxide radical scavenging assay. Furthermore, the T. vulgaris essential oil, which possesses plentiful thymol, exhibited the highest antioxidant activity. For P. acnes-induced secretion of pro-inflammatory cytokines, the essential oils of P. aeruginosa, C. martinii, and T. vulgaris reduced the TNF-α, IL-1β, and IL-8 secretion levels of THP-1 cells.     

不同取代度N,0-羧甲基壳聚糖的抗氧化性能

低聚壳聚糖经醚化得到三种取代度不同的 N,O-羧甲基壳聚糖(NOA、NOB和NOC),本文对其结构进行表征,考察了其对超氧阴离子自由基O2、DPPH 自由基和过氧化氢(H2O2)的清除活性和还原能力.结果表明NOA、NOB 和 NOC 对O2和 DPPH 的清除活性随-OH 位置取代度的降低而升高;对H2O2的清除率随一NH2位置取代度的降低而升高;还原能力大小随其总取代度的升高而增强.