桉叶月见草素B的单体制备及其体内外稳定性研究

采用乙醇提取、大孔树脂吸附、中压柱层析和制备液相等方法从桉叶中分离得到月见草素B(OEB)单体,并对其结构进行了鉴定,分析了OEB在不同极性溶剂中的溶解度,同时考察了热处理条件、p H值及酶的作用对OEB损失率的影响,然后追踪了其在小鼠体内代谢过程,以综合评价OEB的体内外稳定性。结果表明:桉叶醇提所得粗提物经大孔树脂吸附、柱层析及制备液相纯化后可获得OEB单体化合物,纯度94.85%,得率(以桉叶干质量计)2.50%;OEB在水中的溶解度大于其他有机溶剂,热处理温度、p H值、酶的种类及浓度均对OEB的稳定性有影响,高温(80℃)、碱性条件(p H值7)和胰蛋白酶、脂肪酶对OEB的损失率影响更大,损失率最大可达98.85%;OEB在离体血浆作用后出现新组分且损失明显;OEB在小鼠体内的代谢过程表明其在体内胃肠道中均不稳定、易分解,不能直接进入血液,也不能以原型化合物的形式抵达粪便及尿液中。由此可见,OEB在体内外均不稳定,这将为阐明OEB的体内代谢途径及进一步提高其稳定性提供理论依据。

Preparation and in vitro and in vivo Stability of Oenothein B from Eucalyptus Leaves

Oenothein B( OEB) has strong anti-oxidative and antineoplastic activities. It can be developed into functional health food,food antioxidant and other products. Few researches are done on its application because of a scarcity of nature resources and its low bioavailability. In this article,a method of large scale preparation of OEB from eucalyptus leaves was studied by extracting with ethanol,adsorbing through the macroporous resin,medium pressure column chromatography and preparative liquid phase. The structure of OEB was further identified. In addition,the solubility of OEB was analyzed in different polar solvents. Meanwhile,the loss ratio of OEB was measured by dealing with heating temperature,pH values and enzymes. Finally,the metabolic process of OEB was traced in mice to estimate the stability of OEB in vivo and in vitro comprehensively. The results showed that OEB could be purified by column chromatography and pre-HPLC with the purity of 94. 85% and the yield of 2. 50% in weight of dried eucalyptus. OEB was easily decomposed with maximum 98. 85% by solvents,heating temperature,pH and enzymes with different types and concentration. OEB was disappeared clearly and new components appeared after affecting with plasma in vitro. It was also indicated that OEB was unstable in mice and easy to decompose. It could not be absorbed directly into the blood,and also could not arrive in the feces and urine in the form of prototype compounds. Therefore,OEB is unstable in vivo and in vitro. This result provides theoretical basis for elucidating the metabolic pathway in vivo and in vitro as well as for further study on the improvement of OEB stability.