Laboratory of Biotechnology of Natural Polymers (BIOPOL), Department of Biochemistry, Federal University of Rio Grande do Norte (UFRN), Avenue Salgado Filho S/N, Natal-RN 59078-970, Brazil; E-Mails:
Int J Mol Sci. 2012;13(1):409-26. doi: 10.3390/ijms13010409. Epub 2011 Dec 29.
Xylan is one of most abundant polymer after cellulose. However, its potential has yet to be completely recognized. Corn cobs contain a considerable reservoir of xylan. The aim of this work was to study some of the biological activities of xylan obtained from corn cobs after alkaline extraction enhanced by ultrasonication. Physical chemistry and infrared analyses showed 130 kDa heteroxylan containing mainly xylose:arabinose: galactose:glucose (5.0:1.5:2.0:1.2). Xylan obtained exhibited total antioxidant activity corresponding to 48.5 mg of ascorbic acid equivalent/g of xylan. Furthermore, xylan displayed high ferric chelating activity (70%) at 2 mg/mL. Xylan also showed anticoagulant activity in aPTT test. In antimicrobial assay, the polysaccharide significantly inhibited bacterial growth of Klebsiella pneumoniae. In a test with normal and tumor human cells, after 72 h, only HeLa tumor cell proliferation was inhibited (p < 0.05) in a dose-dependent manner by xylan, reaching saturation at around 2 mg/mL, whereas 3T3 normal cell proliferation was not affected. The results suggest that it has potential clinical applications as antioxidant, anticoagulant, antimicrobial and antiproliferative compounds.
木聚糖是继纤维素之后最丰富的聚合物之一。然而，其潜力尚未得到充分认识。玉米芯中含有相当数量的木聚糖。本工作旨在研究经超声增强碱提取得到的玉米芯木聚糖的一些生物学活性。物理化学和红外分析表明，该木聚糖含有主要为木糖：阿拉伯糖：半乳糖：葡萄糖（5.0:1.5:2.0:1.2）的 130 kDa 杂木聚糖。所得到的木聚糖表现出总抗氧化活性，相当于每克木聚糖 48.5 毫克抗坏血酸当量。此外，木聚糖在 2mg/mL 时表现出高的铁螯合活性（70%）。木聚糖在 aPTT 试验中也显示出抗凝活性。在抗菌试验中，该多糖显著抑制肺炎克雷伯菌的细菌生长。在正常和肿瘤人细胞的试验中，经过 72 小时，木聚糖以剂量依赖的方式抑制了人宫颈癌细胞（HeLa）的增殖（p < 0.05），在约 2mg/mL 时达到饱和，而 3T3 正常细胞的增殖则不受影响。结果表明，它具有作为抗氧化剂、抗凝剂、抗菌剂和抗增殖剂的潜在临床应用。
