目的 建立柱前衍生反相高效液相色谱(RP-HPLC)法测定榅桲多糖中单糖的组成及摩尔比，检测榅桲多糖的蛋白酪氨酸磷酸酯酶1B(PTP1B)抑制活性。方法 采用水提醇沉法提取榅桲多糖，并用PTP1B体外模型进行抑制活性测定。榅桲多糖样品经三氟醋酸(TFA)(2 mo1·L-1)和硫酸(2 mo1·L-1)的混合溶液降解为单糖后，经1-苯基-3-甲基-5-吡唑啉酮(PMP)柱前衍生化，利用RP-HPLC法，检测单糖的PMP衍生物。结果 榅桲多糖中含有甘露糖、鼠李糖、葡萄糖、半乳糖、阿拉伯糖等单糖，摩尔比为0.10 ∶ 0.72 ∶ 1.12 ∶ 4.23 ∶ 4.73。榅桲多糖具有良好的PTP1B抑制活性，其IC50为 2.068 μg·mL-1，初步推测榅桲多糖具有抗Ⅱ型糖尿病的潜力。结论 该方法具有简便、快速、重现性好的特点，可用于榅桲多糖的单糖组成分析及质量控制。

Objective To establish a precolumn derivation RP-HPLC method for the determination of the monosaccharide compositions in Cydonia oblonga Mill. polysaccharides，and to test their inhibitory activities of Cydonia oblonga Mill. polysaccharides on protein tyrosine phosphatase 1B(PTP1B). Methods The polysaccharides were extracted by hot distilled water，and precipitated by alcohol. An in vitro screening model was applied to test the PTP1B inhibitory activities. The polysaccharides were derived with 1-phenyl-3-methyl-5-pyrazolone(PMP) after hydrolyzed with 2 mol·L-1 H2SO4 and trifluoroacetic acid(TFA)，and then the PMP derivates of monosaccharides were separated by RP-HPLC. Results Cydonia oblonga Mill. polysaccharides had the monosaccharide compositions of mannose，rhamnose，glucose，galactose，and arabinose with the molar ratio of 0.10，0.72，1.12，4.23，and 4.73，respectively. Moreover，Cydonia oblonga Mill. polysaccharides showed certain PTP1B inhibitory activity with IC50 value of 2.068 μg·mL-1. Conclusion The method is simple，sensitive，accurate and reliable.It can be applied for the analysis of monosaccharide compositions and the quality control of Cydonia oblonga Mill. polysaccharides.

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