In this study, 2-urea-chitosan oligosaccharide derivatives (2-urea-COS derivatives) and 2,6-diurea-chitosan oligosaccharide derivatives (2,6-diurea-COS derivatives) were successfully designed and synthesized via intermediate 2-methoxyformylated chitosan oligosaccharide. All samples were characterized and compared based on FT-IR, 1H NMR spectroscopy, and elemental analysis. The antifungal effects of COS derivatives were tested against Fusarium oxysporum f. sp. niveum, Phomopsis asparagus, and Botrytis cinereal. Their antioxidant properties, including superoxide radicals' scavenging activity, hydroxyl radicals' scavenging activity, and DPPH radicals' scavenging activity were also explored within different concentrations. COS derivatives bearing urea groups showed improved bioactivity compared with pristine COS and 2,6-diurea-COS derivatives had a higher biological activity than 2-urea-COS derivatives in tested concentrations. Additionally, L929 cells were used to carry out cytotoxicity test of COS and COS derivatives by CCK-8 assay. The results indicated that some of samples showed low cytotoxicity. These findings offered a suggestion that COS derivatives bearing urea groups are promising biological materials.

中文翻译：

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制备2,6-二脲-壳聚糖寡糖衍生物，以有效地提高抗真菌和抗氧化活性。

在本研究中，通过中间体2-甲氧基甲酰化壳聚糖成功地设计并合成了2-脲-壳聚糖低聚糖衍生物（2-脲-COS衍生物）和2,6-二脲-壳聚糖低聚糖衍生物（2,6-二脲-COS衍生物）。寡糖。根据FT-IR，1H NMR光谱和元素分析对所有样品进行表征和比较。测试了COS衍生物对尖孢镰刀菌f的抗真菌作用。sp。Niveum，Phomopsis asparagus和Botrytis cinereal。还研究了它们在不同浓度下的抗氧化性能，包括超氧化物自由基的清除活性，羟基自由基的清除活性和DPPH自由基的清除活性。与原始COS和2相比，带有脲基的COS衍生物具有更高的生物活性，在测试浓度下，6-二脲-COS衍生物具有比2-脲-COS更高的生物活性。另外，通过CCK-8试验，使用L929细胞进行COS和COS衍生物的细胞毒性试验。结果表明一些样品显示出低细胞毒性。这些发现提示带有脲基的COS衍生物是有前途的生物材料。