Studies On Extraction, Separation And Purification Of Aloe-sin

Aloe, a widely utilized plant with high economical and medicial values, increasingly influences people's life nowadays. However, the efficient utilization of the active ingredients in aloe, the mechanism theory research and the application in industrial scale are further to be strengthened. Aloesin, an active natural substance extracted from Aloe, with the structure of C-glucoside-5-methlchromone, is of large potential use. Its research and development has great significance in promoting the aloe industry.In this paper, ethanol is used as the extracting agent. Based on single-factor experiment as well as the HPLC method, the aloesin extraction process is optimized by orthogonal test, which optimzes four factors including alcohol density, solid-liquid ratio, extraction temperature and extraction time. Optimum extraction conditions are as following:after being washed, disinfected, thorn removed, aloe akin and vascular bundle deprvied, Aloe is weighed and shattered into fine particles at 10 mesh. At 60℃, according to the solid-liquid ratio of 1:3.5, aloesin is extracted by adding 95% ethanol. After two times'soaking with 70 minutes each, the supernatant are collected, in which ethanol are recovered by rotation evaporation. Then the solution is treated with liquid-liquid extraction with petroleum ether, ethyl acetate. Crude products are finally in the water phase. The purity of aloesin in crude products rised from 0.3 %o to 9.58%, yield is about 87.2%.And then, the purification process based on HZ-830 resin chromatography was studied. The optimum conditions are as follows:at 25℃, the volume, concentration and flow rate of loading sample were 10 bed volumes (BV),0.5-0.8mg/mL, and 2 BV/h, respectively. Desorption was performed with water at 6BV followed by 5%ethanol at 4BV. The aloesin content is increased from 9.6% to 56.01% with a recovery rate of 75.9%.After that, the second run gets a purity of 80.8% with a recovery rate of 66.5%. After crystallization, a high purity of aloesin product is obtained (about 95% purity). Finally, the research in mechanism of HZ-830 macroporous resin absorption promotes the industrail application of this purification process.