College of Sciences, Inner Mongolia Agricultural University, Hohhot, 010018, China.
College of Sciences, Inner Mongolia Agricultural University, Hohhot, 010018, China; Inner Mongolia Key Laboratory of Soil Quality and Nutrient Resource, Hohhot, 010018, China; Key Laboratory of Agricultural Ecological Security and Green Development at Universities of Inner Mongolia Autonomous Region, Hohhot, 010018, China.
Carbohydr Res. 2022 Nov;521:108667. doi: 10.1016/j.carres.2022.108667. Epub 2022 Sep 7.
Chitooligosaccharides (COS) with two different molecular weights are acylated with four nonpolar amino acids: glycine (Gly), alanine (Ala), valine (Val) and leucine (Leu) to obtain 2-aminoacetyl-chitooligosaccharide (2-GlyCOS), 2-aminopropionyl-chitooligosaccharide (2-AlaCOS), 2-amino-3-methylbutyryl-chitooligosaccharide (2-ValCOS), and 2-amino-4-methylpentanoyl-chitooligosaccharide (2-LeuCOS). The structure of the derivatives was characterized by FT-IR spectroscopy, C NMR spectroscopy, and elemental analysis. The antioxidant activities of the derivatives, such as hydroxyl radical (·OH) scavenging ability, superoxide anion (O·) scavenging ability, reducing ability, and DPPH radical scavenging ability, were investigated using various established systems. Compared with chitooligosaccharide and nonpolar amino acids, all derivatives have strong scavenging ability toward hydroxyl radicals and superoxide anions, and the clearance rate was 19.05% and 67.70% separately. The reducing ability and DPPH free radical scavenging ability of the derivatives are only 0.021Abs and 32.97%. Among them, only 2-AlaLCOS has significant reducing ability, and the value can reach 0.143Abs. The above results showed that the antioxidant activity of some derivatives was higher than that of chitooligosaccharide. The water solubility of the new derivatives was also greatly improved compared to that of nonpolar amino acids. Therefore, the application of 2-aminoacyl-chitooligosaccharides (2-AACOS) in antioxidants has laid a foundation and has certain potential application value in the fields of medicine, agriculture, and animal husbandry.
壳寡糖（COS）具有两种不同的分子量，用四种非极性氨基酸：甘氨酸（Gly）、丙氨酸（Ala）、缬氨酸（Val）和亮氨酸（Leu）进行酰化，得到 2-乙酰氨基壳寡糖（2-GlyCOS）、2-丙酰氨基壳寡糖（2-AlaCOS）、2-氨基-3-甲基丁酰氨基壳寡糖（2-ValCOS）和 2-氨基-4-甲基戊酰氨基壳寡糖（2-LeuCOS）。通过傅里叶变换红外光谱（FT-IR）、碳核磁共振光谱（C NMR）和元素分析对衍生物的结构进行了表征。采用各种建立的系统研究了衍生物的抗氧化活性，如羟基自由基（·OH）清除能力、超氧阴离子（O·）清除能力、还原能力和 DPPH 自由基清除能力。与壳寡糖和非极性氨基酸相比，所有衍生物对羟基自由基和超氧阴离子均具有很强的清除能力，清除率分别为 19.05%和 67.70%。衍生物的还原能力和 DPPH 自由基清除能力仅为 0.021Abs 和 32.97%。其中，只有 2-AlaLCOS 具有显著的还原能力，其值可达 0.143Abs。上述结果表明，一些衍生物的抗氧化活性高于壳寡糖。与非极性氨基酸相比，新衍生物的水溶性也大大提高。因此，2-氨酰壳寡糖（2-AACOS）在抗氧化剂中的应用为其在医药、农业和畜牧业等领域的应用奠定了基础，具有一定的潜在应用价值。
