The invention relates to an extraction method of
tetrandrine and demethyltetrandrine. The extraction method comprises the steps of: uniformly mixing
Stephania tetrandra
powder and quick
lime powder, carrying out
alcohol extraction to obtain total
alkaloid extract, adjusting the pH value to 2-4, extracting, and standing for layering; carrying out alkalization and reduction on the extract liquid to obtain extract, dissolving the extract in
acetone, filtering, concentrating and crystallizing to obtain
tetrandrine crude product, and recrystallizing the
tetrandrine crude product to obtain a tetrandrine product; and adjusting pH value of the acidic
aqueous solution obtained after standing to 9-11, extracting to obtain extract, dissolving the extract in
acetone, filtering, concentrating and crystallizing to obtain demethyltetrandrine crude product, and recrystallizing the demethyltetrandrine crude product to obtain a demethyltetrandrine product. Compared with the prior art, the extraction method has the advantages that: the characteristics of the
solubility difference between free tetrandrine and free demethyltetrandrine and demethyltetrandrine salts generated by reaction between acid and each of tetrandrine and demethyltetrandrine is utilized, tetrandrine and demethyltetrandrine can be separately obtained by adjusting the pH value; the operation
controllability is good, the component loss is low, the extractant can be reused,
benzene is not used in extraction process, and the production cost is low; the extraction method is suitable for industrial production; tetrandrine and demethyltetrandrine products can be simultaneously obtained; and the
raw material utilization rate is effectively improved and the production cost is lowered.