Glycolipids from the red alga Chondria armata (Kutz.) Okamura
Glycolipids from the red alga Chondria armata (Kutz.) Okamura
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DOI：
10.1093/glycob/cwl018
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发表时间：
2006-10-01
期刊：
影响因子：
4.3
通讯作者：
D'Souza, Lisette
中科院分区：
文献类型：
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作者：
Al-Fadhli, Ammar;Wahidulla, Solimabi;D'Souza, Lisette
从红藻粗甲醇提取物的氯仿可溶性组分中分离出3个不同的极性糖脂（PF1-3）。Sephadex LH20凝胶层析的Okamura。采用H-1、H-1相关谱（COSY）、H-1、H-1总谱（TOCSY）、H-1、C-13异核多重量子相干（HMQC）、H-1、C-13异核多重键相关（HMBC）等多维核磁共振（NMR）技术，结合正离子模式下的电喷雾电离质谱（ESI-MS）技术，对它们的结构进行了分析。H-1核磁共振谱的偶联常数和旋转符号表明糖分子在甘油脂中的排他性构型。鉴定出的主要糖脂为(2R)-2- o -（5,8,11,14-二十碳四甲酰基）-3- o - α -d-半乳糖酰基-sn-甘油（GL(2)）、其五乙酸酯（GL(1)）和(2R)-1- o -（棕榈酰基）-2- o -（5,8,11,14,17 -二十碳四甲酰基）-3- o - β -d-半乳糖酰基-sn-甘油（GL(3)）。每一个都被甲醇化得到相同的半乳糖甘油，这在ESI-MS上提供了一个假分子离子，在m/z 309上代表脱酰糖脂和钠化糖部分。此外，在ESI-MS的基础上还鉴定了6种次要糖脂。这些包括1,2-二-o -酰基-3- o -（酰基-6 '-半乳糖酰基）-甘油（GL(1a)），磺酰基糖脂2- o -棕榈酰基-3- o -（6 '-磺基喹啉酰基）-甘油（GL(2a)）及其乙醚衍生物（GL(2b)）， 1-油基-2-棕榈酰基-3- o -半乳糖酰甘油（GL(3a)）和1,2-二酰基磷脂酰甘油（GL(3b)）。GL(1)、GL（1a）和GL（2b）在文献中是新的。其余已鉴定化合物的新颖之处在于其脂肪酸组成的多样性。评价了这些糖脂对病原菌的抗菌性能。白色念珠菌和克雷伯氏菌对PF3的敏感性与标准制霉菌素和链霉素相当。与对照相比，同样的代谢物对新型隐球菌表现出相当大的活性。对屈贺氏志贺氏菌、霍乱弧菌和烟曲霉也有较弱的抑制作用。部分PF2对部分菌株有弱活性，而对其乙酰基衍生物PF1均有抗性。本文首次报道了糖脂类的抗菌活性。
Three distinct fractions containing polar glycolipids (PF1-3) were isolated from the chloroform soluble fraction of crude methanolic extract of red alga Chondria armata (Kutz.) Okamura on gel chromatography over Sephadex LH20. Their structure was elucidated by multidimensional nuclear magnetic resonance (NMR) techniques like H-1, H-1 correlation spectroscopy (COSY), H-1, H-1 total COSY (TOCSY), H-1, C-13 heteronuclear multiple quantum coherence (HMQC), and H-1, C-13 heteronuclear multiple bond correlation (HMBC) complemented by electrospray ionization mass spectrometry (ESI-MS) in the positive ion mode. The coupling constant of the anomeric proton in H-1 NMR spectrum and sign of rotation indicated an exclusive configuration of the sugar molecules in the glycerolipids. Major glycolipids were identified as (2R)-2-O-(5,8,11,14-eicosatetranoyl)-3-O-alpha-d-galactopyranosyl-sn-glycerol (GL(2)), its pentacetate (GL(1)), and (2R)-1-O-(palmitoyl)-2-O-(5,8,11, 14,17-eicosapentanoyl)-3-O-beta-d-galactopyranosyl-sn-glycerol (GL(3)). Each was methanolysed to give the same galactosylglycerol which on ESI-MS provided a pseudomolecular ion at m/z 309 representing deacylated glycolipid with the sodiated sugar moiety. Additionally, six minor glycolipids were also identified on the basis of ESI-MS. These include a 1,2-di-O-acyl-3-O-(acyl-6 '-galactosyl)-glycerol (GL(1a)), sulfonoglycolipids 2-O-palmitoyl-3-O-(6 '-sulfoquinovopyranosyl)-glycerol (GL(2a)) and its ethyl ether derivative (GL(2b)), 1-oleoyl-2-palmitoyl-3-O-galactosyl glycerol (GL(3a)), and 1,2-diacyl phosphatidyl glycerol (GL(3b)). GL(1), GL(1a), and GL(2b) are new to the literature. The novelty of the remaining identified compounds lies in the diversity of their fatty acid composition. Antimicrobial properties of these glycolipids against pathogens were evaluated. The yeast Candida albicans and the bacteria Klebsiella sp. were as sensitive as the standard Nystatin and antibiotic Streptomycin against PF3. Considerable activity was expressed by the same metabolite against the fungus Cryptococcus neoformans as compared to the control. Weak activity against the bacteria Shigella flexineri and Vibrio cholerae and the fungus Aspergillus fumigatus was also observed. Fraction PF2 was weakly active against some strains whereas all of them were resistant to its acetyl derivative PF1. Antimicrobial activity of glycolipids is being reported here for the first time.