The invention discloses a process for extracting
rutin from
sophora japonica, which comprises the following steps of: (1) preparing and crushing
sophora japonica, putting the crashed
sophora japonica into an extraction tank, washing and moistening the crashed
sophora japonica with boiling water, and then, introducing an extraction
solvent for carrying out reverse
percolation extraction, wherein the extraction
solvent is a mixture of saturated
lime water,
borax and
sodium sulfite, the proportioning by weight of the saturated
lime water to the
borax to the
sodium sulfite is 1000:4-6:0.5-1.5, and the pressure of the reverse
percolation extraction is 0.2-0.3MPa; and (2) carrying out
cascade filtration on the reverse
percolation extraction solution, adding
hydrochloric acid after cooling to regulate the pH value to 3-4, crystallizing, taking out crystals, washing the crystals with water to the neutrality, and
drying the crystals to obtain finished products. Compared with the prior art, in the invention, by using reverse percolation extraction to replace percolation extraction and combining the extraction
solvent with special proportioning, the
rutin in the
sophora japonica can be extracted more completely, thus the extraction rate is high, and residues in the percolation solution are few and can be filtered more easily; and the invention has the advantages of simple and convenient operation and short
production cycle, and the product purity can reach more than 97.5%.