【作者】 田秀芳；

【导师】 郭锡坤；

【作者基本信息】 汕头大学 ， 工业催化， 2006， 硕士

【摘要】 将κ-卡拉胶（KC）在酸性条件下降解得到数均分子量为10060的低分子量卡拉胶（LMW-KC）并制成四丁基铵盐，然后溶于N，N-二甲基甲酰胺（DMF）中，以4-二甲基氨基吡啶（DMAP）和三丁基胺作为催化剂，于60℃和80℃分别与琥珀酸酐进行酰化，制备了LMW-KC的O-琥珀酰基化衍生物。同时借助IR、GPC、¹³C NMR、¹H NMR、¹H／¹H COSY、¹³C／¹H HMQC、HMBC、TGA和元素分析等方法对合成过程、产物的结构和性质进行分析表征，并对低分子量κ-卡拉胶及其各衍生物的体外抗氧化活性和抑菌活性进行了初步研究。实验结果表明： 在0.1M的盐酸中对κ-卡拉胶降解1h，得到重均分子量为15350、数均分子量为10060的低分子量κ-卡拉胶，与降解前的κ-卡拉胶相比，其结构单元未被破坏，也没有产生脱硫现象。 在60℃和80℃下反应6 h合成了取代度分别为2.60和2.92的LMW-KC O-琥珀酰基化衍生物。分析发现：低分子量κ-卡拉胶与琥珀酸酐形成单酯化合物，且其二糖重复单元结构没有被破坏。κ-卡拉胶的-（1→3）-β-D-半乳糖-4-SO₄-单元（简写为βGalp4）C2位上的羟基被完全取代，βGalp4 C6位和-（1→4）-α-D-3，6-内醚半乳糖-单元（简写为αAnhy）C2位上的羟基被部分取代。LMW-KC酰化后热稳定性明显增强。 低分子量κ-卡拉胶O-琥珀酰基化衍生物对羟自由基（·OH）和超氧阴离子（O₂^-）及H₂O₂诱导红细胞溶血的清除作用较酰化之前明显增强，尤其是在60℃下反应6h获得的产物，其对·OH和H₂O₂诱导红细胞溶血的清除率可分别高达92.35％和97.14％：且其对O₂^-的清除作用也较其他酰基化产物强，可达到26.2％，几乎是同浓度LMW-KC清除率的2倍。更多还原

【Abstract】 Low-molecular-weight κ-carrageenan （LMW-KC） with the number-average molecular weight of 10060 was achieved by degrading κ-carrageenan （KC） with hydrochloric acid, and then was turned into tetrabutylammonium salts. The salts were dissolved in N, N-dimethylformamide （DMF） and acylated by succinic anhydride at the temperature of 60℃ and 80℃ respectively in the presence of dimethylaminopyridine （DMAP） and tributylamine as catalysts, resulted in O-succinyl derivatives of LMW-KC. Characterization of the title compounds were performed by IR, GPC, 13C NMR, 1H NMR, 1H/1H COSY, 13C/1H HMQC, HMBC and TGA. The antioxidant activities and the antibacterial activities of LMW-KC and its derivatives were studied. The results were showed as follows:Low-molecular-weight κ-carrageenan （LMW-KC） with the number-average molecular weight of 10060 and weight-average molecular weight of 15350 was achieved by degrading κ-carrageenan （KC） with 0.1 mol/L hydrochloric acid for 1h. Compared with κ-carrageenan, the disaccharide repeating units of LMW-KC were not destroyed, and the content of S was not changed.O-succinyl derivatives of low-molecular-weight κ-carrageenan were synthesized at 60 ℃ and 80 ℃ for 6 h, succinoylate substitution of which were 2.60 and 2.92, respectively. Mono-ester derivativies with succinyl group were formed, and the structure of disaccharide repeating units were not destroyed after acylation. Hydroxyl groups at C2 of βGalp4 residues of κ-carrageenan were completely substituted, while those at C6 of βGalp4 residues and C2 of αAnhy residues were partly substituted. The thermal stability of the derivatives was increased apparently.The activities of acylated derivatives for scavenging hydroxyl radical, H₂O₂ and superoxide radial anion were obviously increased. The performance of O-succinyl derivatives at 60℃ for 6h were superior to other derivatives; O-succinyl derivatives scavenging rate for hydroxyl radical and H₂O₂ was as high as 92.35% and 97.14% at 60℃ for 6h, respectively, while activities for superoxide radial anion were nearly two times as high as LMW-KC at the same concentration.更多还原