The invention discloses a method for extracting
juglone from walnut green
husk residue by
microwave reflux, which ueses
chloroform solvent for extraction by a
microwave reflux extraction method, preferably adopting walnut epicarpe (green
husk) residue with higher
juglone content and can be obtained easily as raw materials for extraction. The method is carried out under the optimal extraction condition that the
solid-to-
liquid ratio of walnut green
husk with average grain size of 50 mesh to the
chloroform solvent is between 1:5 and 1:8, and comprises the steps of: subjecting walnut green husk residue to extraction and pumping
filtration at soft fire in
microwave power level and washing the filter residue with
solvent to obtain
juglone extraction liquid, collecting all solutions, and preparing the juglone by decompression, rotary
evaporation and concentration. After all index measurements, the
extraction ratio of the juglone is 92%, the purity of product is 81.5%, and the product yield is 0.20%. The method is rapid and convenient, and has high
extraction ratio, and devices in the method are easy to operate, have low
energy consumption, consume less solvents which are easy to be recovered, and are suitable for the expanded production in factories. Meanwhile, the problem that juglone is heated and decomposed in a traditional method can be effectively avoided, which guarantees the effectiveness of extractives. The method satisfies the
environmental protection and industrialization demands. The extracted juglone can be widely applied, and active ingredients in the juglone have the effects of antibacterial, anticancer and
sedation of
central nervous system, and have wide application prospects in such fields as
medicine,
pesticide, dye,
pH indicator and the like.