B:Thin-Layer Chromatographic Identification Test á201ñ
Test solution
Dissolve a quantity of Extract in methanol to obtain a solution having a concentration of about 25mg per mL.
Standard solution 2
Prepare a solution of ferulic acid in methanol having a concentration of about 1mg per mL.
Application volume:
5µL.
Developing solvent system:
a mixture of methylene chloride,methanol,glacial acetic acid,and water (80:15:2:2).
Spray reagent
Prepare a 5%ferric chloride solution in methanol.
Procedure
Proceed as directed in the chapter,except to dry the plate at 110

and to examine the plate under short-wavelength and long-wavelength UVlight.The chromatogram of
Standard solution 1exhibits bands in the middle third and upper third that correspond to protocatechuic acid and ferulic acid,respectively.Spray the plate with the
Spray reagent,and dry at 110

for 10minutes.The bands due to ferulic acid and protocatechuic acid turn grayish green and orange,respectively.Grayish-green bands become visible in the chromatogram of
Standard solution 1above and below protocatechuic acid indicating the presence of caffeic acid and catechin,respectively.The chromatogram of the
Test solutionexhibits bands due to caffeic acid,protocatechuic acid,and ferulic acid that correspond in color and
RFvalue to those in the chromatogram of
Standard solution 1.
C:Thin-Layer Chromatographic Identification Test á201ñ
Test solution
Use theTest solutionprepared as directed forIdentificationtestB.
Standard solution
Use the Standard solution 1prepared as directed forIdentificationtestB.
Application volume:
5µL.
Developing solvent system:
a mixture of ethyl acetate,formic acid,and water (100:10:6).
Spray reagent:
a mixture of phosphoric acid and alcohol (1:1),containing 1%of vanillin.
Procedure
Proceed as directed in the chapter,except to spray the plate with the
Spray reagent and heat at 110

for 10minutes.Three red bands appear in the middle third of the chromatogram of the
Standard solutioncorresponding to two dimeric procyanidins and catechin.The chromatogram of the
Standard solutionalso exhibits a blue band between the upper band due to upper dimeric procyanidins and the band due to catechin.The chromatogram of the
Test solutioncontains bands that correspond to those found in the chromatogram of the
Standard solution.
D:
Proceed as directed in the following liquid-chromatographic procedure.
Solution A
Use filtered and degassed methanol.
Solution B
Carefully weigh 1g of phosphoric acid,and dilute with water.Transfer to a 1000-mLvolumetric flask,dilute with water to volume,and mix.
Mobile phase
Use variable mixtures of
Solution Aand
Solution Bas directed for
Chromatographic system.Make adjustments if necessary (
see System Suitabilityunder
Chromatography á621ñ).
Standard solution
Dissolve an accurately weighed quantity of
USP Maritime Pine Extract RSin
Solution Ato obtain a solution having a known concentration of about 2mg per mL.Pass through a membrane having a 0.45-µm or finer porosity.
Test solution
Weigh about 20mg of Extract.Add 10mLof Solution A,and sonicate for 10minutes.Pass through a membrane having a 0.45-µm or finer porosity,discarding the first 4mLof the filtrate.
Chromatographic system(see Chromatography á621ñ)
The liquid chromatograph is equipped with a 280-nm detector and a 4.6-mm ×15-cm column that contains base-deactivated packing L7,having less than 5-µm particle size.The column temperature is maintained at 40

.The flow rate is about 1.0mLper minute.The chromatograph is programmed as follows.
Time (minutes) |
Solution A
(%) |
Solution B
(%) |
Elution |
| 0 |
8 |
92 |
equilibration |
| 040 |
8®34 |
92®66 |
linear gradient |
| 4045 |
34®2 |
66®98 |
linear gradient |
| 4550 |
2 |
98 |
isocratic |
| 5052 |
2®8 |
98®92 |
linear gradient |
| 5257 |
8 |
92 |
isocratic |
Chromatograph the
Standard solution,and record the peak responses as directed for
Procedure:the chromatogram obtained is similar to the Reference Chromatogram provided with the
USP Maritime Pine Extract RS;the resolution,
R,between taxifolin and ferulic acid is not less than 3.0;and the tailing factor for taxifolin is not more than 2.0.
Procedure
Separately inject equal volumes (about 10µL)of the Standard solutionand the Test solutioninto the chromatograph,record the chromatograms,and measure the peak areas for catechin,caffeic acid,taxifolin,and ferulic acid,identifying the peaks by comparison of the chromatogram of theStandard solution with the Reference Chromatogram:the chromatogram of theTest solutionexhibits peaks for catechin,caffeic acid,taxifolin,and ferulic acid at the retention times corresponding to those in the chromatogram of theStandard solution.