Extraction Technology Optimization And Content Analysis Of The Main Secondary Metabolites Of Mulberry Leaves

Mulberry is considered as food-medicine herbs, with specific nutritional and medicinalvalues. The alkaloids, flavonoids and polysaccharides existed in mulberry leaves exhibitanti-tumor, inhibition of enzymatic activity, anti-virus and other biological activities. Mostof these components are plant secondary metabolites. In this paper, the extractiontechnology of the main secondary metabolites flavonoids, polysaccharides and alkaloidswere optimized, the total content of flavonoids, polysaccharides and alkaloids of mulberryleaves from119germplasm resources were analysed.Based on single factor experiments, a three level, three variable central compositedesign was carried out to establish a quadratic regression model for the extraction efficiencyof total flavonoids as a function of extraction time, ethanol concentration andmaterial-solvent ratio. The optimum extraction conditions were obtained as follows:extraction temperature50℃, ethanol concentration80%, material-solvent ratio1:40(g/mL),and extraction time40min. Under these conditions, the predicted total fpavonoids extractionefficiency was1.6%, and the experimental value1.59%. The result indicated that theestablished model well predicted the extraction efficiency of total flavonoids from mulberryleaves.Based on single factor experiments, a three level, three variable central compositedesign was carried out to establish a quadratic regression model for the extraction efficiencyof total polysaccharides as a function of extraction time, extraction temperature andmaterial-solvent ratio. The optimum extraction conditions were obtained as follows:extraction temperature70℃, material-solvent ratio1:30(g/mL), and extraction time40min.Under these conditions, the predicted total polysaccharides extraction efficiency was3.6%,and the experimental value3.56%. The result indicated that the established model wellpredicted the extraction efficiency of total polysaccharides from mulberry leaves.Ultrasonic-assisted extraction technology of total alkaloids was optimized usingorthogonal experiment of a4-variable,3-levels design based on single factor experiments.By orthogonal intuitive analysis, Impact on extraction efficiency factors were obtained asfollows: ethanol concentration> extraction temperature> material-solvent ratio> extractiontime. The optimum extraction conditions were obtained as follows: ethanol concentration95%, extraction temperature50℃, material-solvent ratio1:30(g/mL), extraction time30 min. Under these conditions, total alkaloids extraction efficiency was2.16%.According to the optimum conditions, the total flavonoids, polysaccharides andalkaloids of119accessions of morus alba Linn. and morus atropurpurea Roxb. leaf sampleswere extracted, and the contents were analysed. A active component database wasestablished using Matlab software. And the difference of frequencies distribution of totalcontent, content differences of species, habitat and MANOVA cluster analysis wereconducted. Contents of total flavonoids, total polysaccharides and total alkaloids of morusatropurpurea Roxb. were significantly higher than that of morus alba Linn. It is obviousdifferences of germplasm from different habitat. Therefore the developed process wouldprovide the test and analysis methods, and theoretical reference for multi-functionaldevelopment of quality standards, and developing modern medicinal mulberry resources.