The invention belongs to the field of
natural product chemistry, and relates to extraction, separation and purification of natural products, in particular to a technical method for extracting high-purity total alkaloids from dyers woad leaf. The method for preparing
indigo and
indirubin from dyers woad leaf is mainly characterized by comprising the following steps of:
drying, pulverizing and sieving dyers woad leaves; heating and extracting by
reflux by an
ethanol solution containing
sodium hydroxide; recovering
ethanol from filtrate; concentrating the filtrate, regulating the pH to be neutral by a
hydrochloric acid solution, centrifuging; dissolving the precipitate by the
hydrochloric acid solution, and centrifuging to obtain supernatant for later use; performing
microfiltration on the supernatant in membrane separation equipment; loading the
stock solution after
microfiltration on a resin column for absorption, then eluting with water to remove
water soluble impurities, discarding the water eluent; eluting with
aqueous ethanol, collecting the eluent; and recovering
ethanol from the eluent, concentrating and
drying to obtain a dark red product. The method has the advantages of low production cost of the products, simple process
route, smaller
toxicity of the extraction
solvent and short extraction cycle, and is suitable for application in industrial production. Based on the advantages, the method can further promote industrialized development of the dyers woad leaf extract as a multifunctional product such as a
medicine, a health product and the like.