Synthesis of Trinorditerpenoid Derivatives and Evaluation of Antimicrobial and Cytotoxic Activity

The synthesis of optically active trinorditerpenes was carried out, and their antimicrobial and antitumor activity was tested. The synthetic derivative 12-hydroxypodocarpa-8,11,13-triene (7) showed GI₅₀ at 6.6 µM against breast cancer MDA-MB-435 (LC₅₀ = 50.9 µM and log10 GI₅₀ = −5.18). The 12-acetyloxypodocarpa-8,11,13-triene (8) showed GI₅₀ at 12.1 µM against leukemia RPMI-8226 (LC₅₀ = 76.1 µM and log₁₀GI₅₀ = −4.92).__________Published in Khimiya Prirodnykh Soedinenii, No. 3, pp. 255–259, May–June, 2005.     

Review: Preparation and Application of Magnetic Chitosan Derivatives in Separation Processes

Chitosan is one of the most abundant natural polysaccharide in nature. Due to its unique properties, chitosan has fascinated the scientific community since its discovery. When modified with other materials and combined with magnetic particles, the resulting composite material, a magnetic chitosan derivative, is provided with three significant characteristics. First, chitosan has excellent properties for preconcentration/extraction, such as adsorption and chelating effects, low cost, and nontoxicity. Second, new functional groups have enhanced the properties of chitosan that include water solubility, stability, recyclability, and enhanced adsorption capacity. Finally, due to the efficient and fast adsorption processes, as well as simple and convenient magnetic separation, the magnetic adsorbents greatly reduce the time of sample handling. In this article, recent synthesis and modification methods of magnetic chitosan derivatives are reviewed along with some applications in analytical separations.     

硫脲壳聚糖微量银配合物的制备及抑菌活性

由硫脲壳聚糖和微量的AgNO3反应得到硫脲壳聚糖Ag+配合物。 通过红外光谱对其结构进行了表征。 研究了壳聚糖、硫脲壳聚糖、硫脲壳聚糖-Ag+配合物及AgNO3对大肠杆菌和金黄葡萄球菌的抑菌活性,并测定了其最低抑菌浓度(MIC)和最低杀菌浓度(MBC)。 结果表明,硫脲壳聚糖-Ag+配合物的抑菌活性强于壳聚糖和硫脲壳聚糖,且其MIC和MBC均为100 mg/L（游离Ag+含量为0.032 mg/L）,低于AgNO3的MIC和MBC（均为120 mg/L）。     

Antimicrobial Properties of Chitosan and Chitosan Derivatives in the Treatment of Enteric Infections

Antibiotics played an important role in controlling the development of enteric infection. However, the emergence of antibiotic resistance and gut dysbiosis led to a growing interest in the use of natural antimicrobial agents as alternatives for therapy and disinfection. Chitosan is a nontoxic natural antimicrobial polymer and is approved by GRAS (Generally Recognized as Safe by the United States Food and Drug Administration). Chitosan and chitosan derivatives can kill microbes by neutralizing negative charges on the microbial surface. Besides, chemical modifications give chitosan derivatives better water solubility and antimicrobial property. This review gives an overview of the preparation of chitosan, its derivatives, and the conjugates with other polymers and nanoparticles with better antimicrobial properties, explains the direct and indirect mechanisms of action of chitosan, and summarizes current treatment for enteric infections as well as the role of chitosan and chitosan derivatives in the antimicrobial agents in enteric infections. Finally, we suggested future directions for further research to improve the treatment of enteric infections and to develop more useful chitosan derivatives and conjugates.     

壳聚糖及其衍生物对重金属离子的吸附

壳聚糖的结构中含有大量的—NH₂和—OH,因此其对重金属离子有优良的吸附作用。但是作为天然高分子物质,壳聚糖的吸附性能又受到其自身物理形态、原料来源、脱乙酰度及体系pH值的影响,因此,对其进行物理和化学改性是提高壳聚糖吸附性能、扩大应用范围的必要手段。本文综述了壳聚糖的改性方法及其衍生物对重金属离子吸附作用的研究进展,并对其在重金属污染废水处理方面的前景作了展望。     

Biomaterials Based on Chitosan and Its Derivatives and Their Potential in Tissue Engineering and Other Biomedical Applications—A Review

In the times of dynamically developing regenerative medicine, more and more attention is focused on the use of natural polymers. This is due to their high biocompatibility and biodegradability without the production of toxic compounds, which means that they do not hurt humans and the natural environment. Chitosan and its derivatives are polymers made most often from the shells of crustaceans and are biodegradable and biocompatible. Some of them have antibacterial or metal-chelating properties. This review article presents the development of biomaterials based on chitosan and its derivatives used in regenerative medicine, such as a dressing or graft of soft tissues or bones. Various examples of preparations based on chitosan and its derivatives in the form of gels, films, and 3D structures and crosslinking products with another polymer are discussed herein. This article summarizes the latest advances in medicine with the use of biomaterials based on chitosan and its derivatives and provides perspectives on future research activities.     

萘甲基苯并咪唑衍生物的合成、表征及其杀菌活性

萘甲基苯并咪唑衍生物的合成、表征及其杀菌活性;萘甲基苯并咪唑衍生物; 合成; 晶体结构; 杀菌活性     

新型异噻唑啉酮化合物的合成和抑菌活性研究

合成了10个2-取代异噻唑啉酮化合物, 其中7个未见文献报道. 所有目标物的结构都经元素分析, ¹H NMR, MS及IR证实, 并将其中8个化合物对五种细菌进行了抑菌活性测试. 与市售农药20%三环唑、70%威尔达甲托以及三氯新的抑菌活性进行对比, 发现它们对五种有害菌种均有极强的杀菌活性.     

Deformylated Gramicidin A and Its Derivatives Showing High Antimicrobial Activity and Low Hemolytic Toxicity

Gramicidin A is a natural peptide, which shows high antimicrobial activity to Gram‐positive bacteria. However, the hemolytic toxicity prevents its therapeutic usage. We demonstrated that by simply removing the formyl group at the N terminus, the hemolytic toxicity of the peptide could be obviously decreased. The deformylated gramicidin A ( 1 ) could efficiently insert into the lipid bilayer to form transmembrane channels. The peptide can also selectively insert into the membrane of Gram‐positive bacteria but not that of erythrocytes, leading to its high antimicrobial activity and very low hemolytic toxicity. The derivation of 1 could be achieved by decoration at the terminal NH₂ group, which also produced peptides showing high activity and low hemolytic toxicity. This derivation method provided us with an efficient strategy to build a library for future activity and cytotoxicity screening in vitro and in vivo.     

Contribution of Aldehydes and Their Derivatives to Antimicrobial and Immunomodulatory Activities

Essential oils (EOs) are intricate combinations of evaporative compounds produced by aromatic plants and extracted by distillation or expression. EOs are natural secondary metabolites derived from plants and have been found to be useful in food and nutraceutical manufacturing, perfumery and cosmetics; they have also been found to alleviate the phenomenon of antimicrobial resistance (AMR) in addition to functioning as antibacterial and antifungal agents, balancing menstrual cycles and being efficacious as an immune system booster. Several main aldehyde constituents can be found in different types of EOs, and thus, aldehydes and their derivatives will be the main focus of this study with regard to their antimicrobial, antioxidative, anti-inflammatory and immunomodulatory effects. This brief study also explores the activity of aldehydes and their derivatives against pathogenic bacteria for future use in the clinical setting.     

壳聚糖及其衍生物抗菌活性的研究进展

壳聚糖是自然界目前发现的唯一碱性多糖,具有自然来源丰富,生物相容性好,可被生物降解,安全无毒和抗菌性强等许多天然的优良特性,现其广谱抗菌性已得到广泛的认可,但较差的水溶性限制了它的进一步应用。因此,通过一定的改性方法制备壳聚糖衍生物以提高其水溶性,是目前壳聚糖研究方面的热点之一。本论文就近年来几种常见的壳聚糖亲水改性方法及其衍生物在抗菌方面的应用进展进行综述,以期对壳聚糖的深入研究提供参考。     

喹唑啉类衍生物的合成及抗菌活性研究进展

喹唑啉类化合物具有广泛的生物活性,在农药和医药领域受到了人们越来越多的关注.将不同药效团引入到喹唑啉骨架中,经结构修饰后能产生一系列具有抗菌活性的喹唑啉类化合物.本工作对近年来该类化合物的研究进行了综述,并对其发展前景进行了展望.     

壳聚糖及其衍生物应用于肥胖治疗的研究进展

肥胖是并发高血脂、脂肪肝、糖尿病和心脑血管损害等疾病的主要危险因子,减肥药物（食品）是一种有效的控制体重的手段。壳聚糖对脂肪和胆固醇具有良好的吸附性能,正在成为一种新型的减肥药物（食品）。结合本课题研究方向,综述了药用壳聚糖及其衍生物在治疗肥胖及其并发症方面应用的研究进展。通过在壳聚糖C6住-OH上改性制备了水溶性、油溶性和两亲性良好的壳聚糖衍生物,并通过动物试验研究了其减肥功效。     

芳香基苯并咪唑衍生物的合成、表征及抑菌活性研究

在微波辐射下,通过二茂铁磺酰氯和相应的苯并咪唑合成了4种芳香基苯并咪唑衍生物。经^1H NMR、MS及元素分析确证产物结构。通过X线衍射测定了化合物4a的晶体结构。用琼脂稀释法测定化合物抑菌活性,并与对照药剂50%多菌灵可湿性粉剂比较,结果表明化合物4a～4d对番茄早疫病菌、烟草赤星病菌和小麦赤霉病菌有与对照药剂近似的抑菌活性。     

壳聚糖含磷衍生物的合成、表征及其应用研究*

壳聚糖是一种可再生的天然碱性多糖,具有多种优良的特性。但是,由于壳聚糖本身的溶解性很差,只能溶解在一些稀酸中,这就在一定程度上限制了其进一步的研究与应用。因此,通过修饰改性提高其已有功能、赋予新的功能是壳聚糖重要的研究领域。其中,通过磷酸化或磷酰化改性是壳聚糖改性研究的方向之一。本文综述了在壳聚糖链上引入含磷/膦基团合成壳聚糖含磷衍生物的研究进展;介绍并讨论了壳聚糖含磷衍生物的合成及纯化方法;对壳聚糖含磷衍生物结构、性能及表面形貌的表征进行了详细的阐述;对壳聚糖含磷衍生物的应用进行了总结,并展望了壳聚糖含磷衍生物未来的应用前景。     

Synthesis and Antimicrobial Evaluation of 1,4-Naphthoquinone Derivatives as Potential Antibacterial Agents

1,4-Naphthoquinones are an important class of compounds present in a number of natural products. In this study, a new series of 1,4-naphthoquinone derivatives were synthesized. All the synthesized compounds were tested for in vitro antimicrobial activity. In this present investigation, two Gram-positive and five Gram-negative bacterial strains and one pathogenic yeast strain were used to determine the antibacterial activity. Naphthoquinones tested for its antibacterial potencies, among seven of them displayed better antimicrobial activity against Staphylococcus aureus (S. aureus; 30–70 μg/mL). Some of the tested compounds showed moderate to low antimicrobial activity against Pseudomonas aeruginosa (P. aeruginosa) and Salmonella bongori (S. bongori; 70–150 μg/mL). In addition, most active compounds against S. aureus were evaluated for toxicity to human blood cells using a hemolysis assay. For better understanding, reactive oxygen species (ROS) generation, time-kill kinetic study, and apoptosis, necrosis responses were investigated for three representative compounds.