超声波辅助杂多酸提取竹叶多糖工艺优化及其生物活性研究

以竹叶为原料,采用磷钨酸耦合超声波提取竹叶多糖,通过单因素实验结合响应面试验优化竹叶多糖的提取工艺。利用傅里叶红外光谱(FT-IR)、电子扫描显微镜(SEM)和高效阴离子色谱(HPAE),对竹叶多糖结构、单糖组成进行了初步的表征和检测,并研究了竹叶多糖的体外相关生物活性。结果表明,提取竹叶多糖最优条件为超声温度80℃、提取时间2 h、料液比1:20 g/mL、磷钨酸质量分数4.50%、超声功率300 W,该条件下竹叶多糖的得率为9.89%。竹叶多糖是一种具有α-型吡喃糖苷键结构的杂多糖,由L-岩藻糖、L-鼠李糖、L-阿拉伯糖、D-葡萄糖、D-半乳糖和D-木糖组成。竹叶多糖对还原力、2,2-联氮-二(3-乙基-苯并噻唑-6-磺酸)二铵盐自由基(ABTS)和1,1-二苯基-2-三硝基苯肼自由基(DPPH)均具有一定的抑制作用,且体外抗氧化活性的能力与竹叶多糖的质量浓度呈现正相关。在0.25~4.00 mg/mL范围内,随着竹叶多糖质量浓度的增加,其对癌细胞HepG-2的增殖抑制率逐渐增大。当竹叶多糖质量浓度为4.0 mg/mL时,对肿瘤细胞HepG-2增殖的抑制率达到半抑制浓度,说明竹叶多糖具有一定的抗肿瘤活性。

Optimization of Preparation and Its Biological Evaluations of Bamboo Leaves Polysaccharides Extracted by Ultrasonic Extraction Assisted by Heteropoly Acid

Bamboo leaf polysaccharide was extracted by phosphotungstic acid coupled with ultrasonic. The extraction process was optimized by single factor experiment combined with response surface experiment. The structural characterization and monosaccharide composition of polysaccharides from bamboo leaves were analyzed by Fourier transform infrared chromatography(FT-IR),scanning electron microscope(SEM)and high performance anion chromatography(HPAEC). And the related biological activities were evaluated. The results showed that the optimum extraction conditions for crude polysaccharides from bamboo leaves were as follows:Ultrasonic temperature 80℃,extraction time 2 h,liquid-solid ratio 1:20 g/mL,phosphotungstic acid mass fraction 4.50%,ultrasonic power 300 W. Under these conditions,the yield of polysaccharide was 9.89%. The bamboo leaves polysaccharides possessed the structure of α-pyranosides and consisted of L-fucose,L-rhamnose,L-arabinose,D-glucose,D-galactose and D-xylose. The polysaccharides from bamboo leaves exhibited antioxidant activities in reducing power,scavenging of DPPH and ABTS free radicals. Moreover,the abilities of antioxidant activity were positively correlated with the concentration of polysaccharides. The inhibitory effect of polysaccharides on the proliferation of cancer cells increased gradually with the concentration increasing of 0.25~4.00 mg/mL. When the concentration was 4.0 mg/mL,the inhibition of tumor cell HepG-2 proliferation was nearly 50%,indicating that polysaccharides from bamboo leaves had potential anti-tumor activity.