Casanthranol
»Casanthranol is obtained from Cascara Sagrada.It contains in each 100g not less than 20.0g of total hydroxyanthracene derivatives calculated on the dried basis,calculated as cascaroside A.Not less than 80percent of the total hydroxyanthracene derivatives consists of cascarosides,calculated as cascaroside A.
Packaging and storage— Preserve in tight,light-resistant containers,at a temperature not exceeding 30.
Loss on drying á731ñ— Dry it in vacuum at 80for 16hours:it loses not more than 10.0%of its weight.
Residue on ignition á281ñ: not more than 4.0%.
Assay for total hydroxyanthracene derivatives— [NOTE1—Perform all extractions by shaking vigorously,and allow all phases to separate completely before transferring.Entrainment of aglycones into the aqueous phase,as indicated by a value of less than 2.6for the ratio of the absorbance of the final solution at 515nm to that at 440nm,may lead to false results.NOTE2—Throughout this assay,use 1Nsodium hydroxide that is prepared without added barium ions as directed for Volumetric Solutionsin the section Reagents,Indicators,and Solutions.]
Ferric chloride solution— Dissolve 100g of ferric chloride in water to make 100mL.
Assay solution— Mix a portion of Casanthranol,and transfer an accurately weighed quantity of about 500mg to a 100-mLvolumetric flask.Add about 30mLof 70percent alcohol,swirl to dissolve,dilute with 70percent alcohol to volume,and mix.Quickly filter through soft,rapid-flow filter paper,taking precautions to minimize loss by evaporation.
Assay preparation— Pipet 10mLof Assay solutioninto a separatory funnel containing 5mLof water and 2drops of 1Nhydrochloric acid.Extract with 40mLof methylene chloride,and transfer the lower layer to a second separatory funnel.Add 10mLof water to the second separatory funnel,and shake.Allow to separate,discard the lower layer,and transfer the water layer to the first separatory funnel.Extract the combined water layers with 40mLof methylene chloride,and transfer the lower layer to the second separatory funnel.Add 10mLof water to the second separatory funnel,and shake.Allow to separate,and discard the lower layer.Transfer the combined water layers,with the aid of water,to a 50-mLvolumetric flask,filtering through a small pledget of cotton,water-wet,dilute with water to volume,and mix.
Procedure— Pipet 10mLof Assay preparationinto a flask containing 2mLof Ferric chloride solutionand 12mLof hydrochloric acid.Attach a condenser arranged for refluxing,and heat for 3hours by keeping the flask immersed in boiling water or continuously exposed to steam heat.Cool,wash down the condenser,and transfer to a separatory funnel with the aid of 4mLof 1Nsodium hydroxide and five 6-mLportions of water.Extract with 20mLof methylene chloride,and transfer the lower layer to another separatory funnel.Repeat the extraction with three additional 20-mLportions of methylene chloride,wash the combined methylene chloride extracts with two 10-mLportions of water,shaking each time for 2minutes,and discard the water washings.Transfer the washed methylene chloride extract to a 100-mLvolumetric flask,dilute with methylene chloride to volume,and mix.Evaporate a 20.0-mLportion carefully on a water bath to dryness,and dissolve the residue in 10.0mLof a 1in 200solution of magnesium acetate in methanol.Determine the absorbance against methanol as a reference,in 1-cm cells at the wavelength of maximum absorbance at about 515nm.Calculate the quantity,in mg,of total hydroxyanthracene derivatives in the portion of Casanthranol taken by the formula:
155AU,
in which AUis the absorbance of the solution from the Assay preparation.
Assay for cascarosides— [NOTE1—Perform all extractions by shaking vigorously,and allow all phases to separate completely before transferring.Entrainment of aglycones into the aqueous phase,as indicated by a value of less than 2.7for the ratio of the absorbance of the final solution at 515nm to that at 440nm,may lead to false results.NOTE2—Throughout this assay,use 1Nsodium hydroxide that is prepared without added barium ions as directed for Volumetric Solutionsin the section Reagents,Indicators,and Solutions.]
Ferric chloride solutionand Assay solution— Prepare as directed in the Assay for total hydroxyanthracene derivatives.
Assay preparation— Pipet 10mLof Assay solutioninto a separatory funnel containing 5mLof water and 2drops of 1Nhydrochloric acid.Extract with 40mLof methylene chloride,and transfer the lower layer to a second separatory funnel.Add 10mLof water to the second separatory funnel,and shake.Allow to separate,discard the lower layer,and transfer the water layer to the first separatory funnel.Extract the combined water layers with 40mLof methylene chloride,and transfer the lower layer to the second separatory funnel.Add 10mLof water to the second separatory funnel,and shake.Allow to separate,discard the lower layer,and transfer the water layer to the first separatory funnel.Extract the combined aqueous phase with 30mLof clear,freshly prepared water-saturated ethyl acetate,and transfer the water layer to another separatory funnel.Repeat the extraction with two additional 30-mLportions of the freshly prepared water-saturated ethyl acetate.Add 5mLof water to the combined ethyl acetate extracts,shake,allow the phases to separate,discard the ethyl acetate extracts,and add 30mLof the freshly prepared water-saturated ethyl acetate to the water wash.Shake,allow the phases to separate,and discard the ethyl acetate phase.Transfer the combined aqueous phases,with the aid of water,to a 50-mLvolumetric flask,filtering through a small pledget of cotton,water-wet,dilute with water to volume,and mix.
Procedure— Pipet 15mLof Assay preparationinto a flask containing 2mLof Ferric chloride solutionand 12mLof hydrochloric acid.Attach a condenser arranged for refluxing,and heat for 3hours by keeping the flask immersed in boiling water or continuously exposed to steam heat.Cool,wash down the condenser,and transfer to a separatory funnel with the aid of 4mLof 1Nsodium hydroxide and five 6-mLportions of water.Extract with 20mLof methylene chloride,and transfer the lower layer to another separatory funnel.Repeat the extraction with three additional 20-mLportions of methylene chloride,wash the combined methylene chloride extracts with two 10-mLportions of water,shaking each time for 2minutes,and discard the water washings.Transfer the washed methylene chloride extract to a 100-mLvolumetric flask,dilute with methylene chloride to volume,and mix.Evaporate a 20.0-mLportion carefully on a water bath to dryness,and dissolve the residue in 10.0mLof a 1in 200solution of magnesium acetate in methanol.Determine the absorbance,against methanol as a reference,in 1-cm cells at the wavelength of maximum absorbance at about 515nm.Calculate the quantity,in mg,of cascarosides in the portion of Casanthranol taken by the formula:
103.5AU,
in which AUis the absorbance of the solution from the Assay preparation.
Auxiliary Information— Staff Liaison:Gabriel I.Giancaspro,Ph.D.,Senior Scientist and Latin American Specialist
Expert Committee:(DSB)Dietary Supplements:Botanicals
USP28–NF23Page 364
Phone Number:1-301-816-8343