The present disclosure provides a preparation method of dihydroquercetin, belonging to the field of synthesis of drugs. The method includes steps of: adjusting reaction solvent water to be alkaline with an alkalizing reagent, to obtain an alkaline aqueous solution; dissolving quercetin dihydrate in the alkaline aqueous solution, and adding a sulfite binary combined reducing agent to carry out reduction reaction, to obtain an endpoint reduction reaction solution; diluting the endpoint reduction reaction solution with water, and then acidizing, aging, and filtering the resultant to obtain a filtrate and a filter cake; subjecting the filtrate to extraction, washing, drying, and vacuum concentration to obtain a concentrated crude product; and repeatedly crystallizing the concentrated crude product to obtain dihydroquercetin. The preparation method of the present disclosure has readily available raw materials, a simple process, and low production costs, and is particularly suitable for industrial production.

Provided is a method for decomposing a flavonoid glycoside, wherein a flavonoid glycoside is decomposed into a flavonoid by heat-treating a flavonoid glycoside-containing raw material in the presence of an alcohol in a sealed container at a temperature exceeding the boiling point of the alcohol under atmospheric pressure.

Provided is a method for decomposing a flavonoid glycoside, wherein a flavonoid glycoside is decomposed into a flavonoid by heat-treating a flavonoid glycoside-containing raw material in the presence of an alcohol in a sealed container at a temperature exceeding the boiling point of the alcohol under atmospheric pressure.

Provided is a method for decomposing a flavonoid glycoside, wherein a flavonoid glycoside-containing raw material is hydrothermally treated to decompose a flavonoid glycoside into a flavonoid.

Provided is a method for decomposing a flavonoid glycoside, wherein a flavonoid glycoside-containing raw material is hydrothermally treated to decompose a flavonoid glycoside into a flavonoid.

The present disclosure provides a semi-synthetic method of dihydroquercetin, belonging to the field of synthesis of organic drugs. The semi-synthetic method includes the following steps: adding quercetin dihydrate to solvent water adjusted to be alkaline with an alkalizing reagent, heating and stirring to dissolve the mixture, and then adding thiourea dioxide under the protection of an inert gas to perform a reduction reaction, to obtain an endpoint reduction reaction solution; diluting the endpoint reduction reaction solution with water and cooling the resultant, and then acidizing, aging, and filtering the resultant to obtain a filtrate and a filter cake; extracting, washing, drying, concentrating, and repeatedly crystallizing the filtrate to obtain dihydroquercetin; and recycling the filter cake after being washed.

The present disclosure provides a semi-synthetic method of dihydroquercetin, belonging to the field of synthesis of organic drugs. The semi-synthetic method includes the following steps: adding quercetin dihydrate to solvent water adjusted to be alkaline with an alkalizing reagent, heating and stirring to dissolve the mixture, and then adding thiourea dioxide under the protection of an inert gas to perform a reduction reaction, to obtain an endpoint reduction reaction solution; diluting the endpoint reduction reaction solution with water and cooling the resultant, and then acidizing, aging, and filtering the resultant to obtain a filtrate and a filter cake; extracting, washing, drying, concentrating, and repeatedly crystallizing the filtrate to obtain dihydroquercetin; and recycling the filter cake after being washed.

The present invention relates to a method for isolating flavonoids such as cochlioquinone or chrysoeriol from a rice plant inoculated with a whitebacked planthopper. The method of the present invention, for example, facilitates not only the fast production of flavonoids such as cochlioquinone or chrysoeriol but also the mass-production of flavonoids such as cochlioquinone or chrysoeriol with high efficiency in addition to the advantage of saving costs. Therefore the method of the present invention can be effectively used for the production of flavonoids such as cochlioquinone or chrysoeriol and also be used in various fields using the same.

The present invention relates to a method for isolating flavonoids such as cochlioquinone or chrysoeriol from a rice plant inoculated with a whitebacked planthopper. The method of the present invention, for example, facilitates not only the fast production of flavonoids such as cochlioquinone or chrysoeriol but also the mass-production of flavonoids such as cochlioquinone or chrysoeriol with high efficiency in addition to the advantage of saving costs. Therefore the method of the present invention can be effectively used for the production of flavonoids such as cochlioquinone or chrysoeriol and also be used in various fields using the same.

Provided is a method for decomposing a flavonoid glycoside, wherein a flavonoid glycoside-containing raw material is hydrothermally treated to decompose a flavonoid glycoside into a flavonoid.