竹叶内酯的提取及纯化工艺研究

The Study of Extraction and Purification of Lactones from Bamboo Leaves

摘要: 本文探索了竹叶内酯的提取及纯化工艺。首先，以预处理后的竹叶为原料，采用乙醇为提取剂，提取竹叶内酯。以提取率为评价指标，采用单因素试验，确定了乙醇浓度、料液比、提取温度和时间对内酯提取的影响。在此基础上，采用L₉(3⁴)正交试验，优化了竹叶内酯的提取工艺条件，其结果为：乙醇浓度40%，液料比15:1，提取温度90℃，提取时间3 h。然后，将浸提液离心，将上清液浓缩后，分别用聚酰胺、DM301、D101、HP-20和AB-8五种树脂进行纯化。以静态吸附率和解吸率为评价指标，考察树脂种类对内酯纯化的影响。结果表明：用聚酰胺纯化时，其对竹叶内酯有较好的吸附率和解吸率，且有利于内酯与黄酮的分离。所以，选择聚酰胺为最佳吸附树脂。然后，将浓缩后的提取液上柱，用20%乙醇洗脱，得到的流出液依次浓缩及冷冻干燥后，获得竹叶提取物，其内酯的得率(按原始竹叶算)和纯度分别为9.44‰和46.2%。

Abstract: In this article, the extraction and purification of the lactones from the bamboo leaves were studied. First, after pretreatment of bamboo leaves, the lactones were extracted with ethanol in terms of the extraction rate of lactones. Then, the optimal parameters, such as concentration of enthanol, solid-liquid ratio, temperature and time of extraction were determined in single factor experiments. Finally, the best extraction condition was optimized in an orthogonal experiment with four factors and three levels (L₉(3⁴)). The results indicated that the optimal conditions were 40% of ethanol concentration, liquid-solid ratio 15:1, extraction temperature at 90˚C and extraction duration of 3 h. After centrifugation of the extract, the supernatant was concentrated and then subjected to purification by polyamide resins, DM301, D101, HP-20 and AB-8, respectively. Taken the static adsorption and desorption rate as evaluation indexes, the result showed that polyamide had better adsorption and desorption rate for bamboo lactone than the others, which was also favorable for the separation of lactones and flavonoids from bamboo leaves. Therefore, polyamide was chosen as the best resin. Subsequently, after concentration, the extract was subjected to the column separation, followed by elution with 20% ethanol before the effluent was collected. Finally, after lyophilization and concentration in turn, the extract was collected, in which the yield (according to the original bamboo leaves) and purity of lactones in the extract were 9.44‰ and 46.2%, respectively.