Key Laboratory of Coastal Biology and Bioresource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, China.
University of Chinese Academy of Sciences, Beijing 100049, China.
Molecules. 2017 Aug 31;22(9):1438. doi: 10.3390/molecules22091438.
Chitosan is an abundant and renewable polysaccharide, its derivatives exhibit attractive bioactivities and the wide applications in various biomedical fields. In this paper, two novel cationic chitosan derivatives modified with quaternary phosphonium salts were successfully synthesized via trimethylation, chloride acetylation, and quaternization with tricyclohexylphosphine and triphenylphosphine. The structures and properties of synthesized products in the reactions were characterized by FTIR spectroscopy, ¹H-NMR, P-NMR, elemental and thermogravimetric analysis. The antifungal activities of chitosan derivatives against four kinds of phytopathogens, including , , , and were tested using the radial growth assay in vitro. The results revealed that the synthesized cationic chitosan derivatives showed significantly improved antifungal efficiency compared to chitosan. It was reasonably suggested that quaternary phosphonium groups enabled the obviously stronger antifungal activity of the synthesized chitosans. Especially, the triphenylphosphonium-functionalized chitosan derivative inhibited the growth of most effectively, with inhibitory indices of about 80% at 0.5 mg/mL. Moreover, the data demonstrated that the substituted groups with stronger electron-withdrawing ability relatively possessed greater antifungal activity. The results suggest the possibility that cationic chitosan derivatives bearing quaternary phosphonium salts could be effectively employed as novel antifungal biomaterials for application in the field of agriculture.
壳聚糖是一种丰富且可再生的多糖，其衍生物表现出诱人的生物活性，广泛应用于各个生物医学领域。本文通过三甲胺化、氯乙酰化和三环己基膦及三苯基膦季铵化，成功合成了两种新型的带有季磷盐的阳离子壳聚糖衍生物。采用傅里叶变换红外光谱、1H-NMR、P-NMR、元素分析和热重分析对反应中合成产物的结构和性质进行了表征。采用体外径向生长法测定了壳聚糖衍生物对、、、四种植物病原菌的抗真菌活性。结果表明，与壳聚糖相比，合成的阳离子壳聚糖衍生物表现出显著提高的抗真菌效率。合理推测，季磷基团使合成壳聚糖具有更强的抗真菌活性。特别是三苯基膦功能化壳聚糖衍生物对的抑制作用最为显著，在 0.5mg/mL 时抑制指数约为 80%。此外，数据表明，取代基吸电子能力越强，抗真菌活性越大。这些结果表明，带有季磷盐的阳离子壳聚糖衍生物有可能作为新型抗真菌生物材料，有效应用于农业领域。
