Li Shijie, Xiong Qingping, Lai Xiaoping, Li Xia, Wan Mianjie, Zhang Jingnian, Yan Yajuan, Cao Man, Lu Lun, Guan Jiemin, Zhang Danyan, Lin Ying
School of Chinese Materia Medica, Guangzhou Univ. of Chinese Medicine, Guangzhou, 510006, Guangdong, PR China.
Affiliated Huaian Hospital, Xuzhou Medical College, Huaian, 223002, Jiangsu, PR China.
Compr Rev Food Sci Food Saf. 2016 Mar;15(2):237-250. doi: 10.1111/1541-4337.12161. Epub 2015 Sep 16.
Polysaccharides are ideal natural resources for supplements and pharmaceuticals that have received more and more attention over the years. Natural polysaccharides have been shown to have fewer side effects, but because of their inherently physicochemical properties, their bioactivities were difficult to compare with those of synthetic drugs. Thus, researchers have modified the structures and properties of natural polysaccharides based on structure-activity relationships and have obtained better functionally improved polysaccharides. This review focuses on the major modification methods of polysaccharides, and discusses the effect of molecular modification on their physicochemical properties and bioactivities. Molecular modification methods mainly include chemical, physical, and biological changes. Chemical modification is the most widely used method; it can significantly increase the water solubility and bioactivities of polysaccharides by grafting onto other groups. Physical and biological modifications only change the molecular weight of a polysaccharide, and thereby change its physicochemical properties and bioactivities. Most of the molecular modifications bring about an increase in the antioxidant activity of polysaccharides, and among these, sulfated and acetylated modifications are very common. Furthermore, phosphorylation modification is the most common application to increase antitumor activity, and modified polysaccharides have been shown to have anti-HIV activity as the result of sulfated modification.
多糖是用于补充剂和药物的理想天然资源，多年来受到越来越多的关注。天然多糖已被证明副作用较少，但由于其固有的物理化学性质，其生物活性难以与合成药物相比较。因此，研究人员基于构效关系对天然多糖的结构和性质进行了修饰，并获得了功能得到更好改善的多糖。本文综述了多糖的主要修饰方法，并讨论了分子修饰对其物理化学性质和生物活性的影响。分子修饰方法主要包括化学、物理和生物学变化。化学修饰是应用最广泛的方法；通过接枝到其他基团上，它可以显著提高多糖的水溶性和生物活性。物理和生物学修饰仅改变多糖的分子量，从而改变其物理化学性质和生物活性。大多数分子修饰会使多糖的抗氧化活性增加，其中硫酸化和乙酰化修饰非常常见。此外，磷酸化修饰是增加抗肿瘤活性最常见的应用，硫酸化修饰的结果表明修饰后的多糖具有抗HIV活性。
