Powdered Echinacea pallida Extract
Powdered Echinacea pallida Extract is prepared from Echinacea pallida roots by extraction with hydroalcoholic mixtures or other suitable solvents. The ratio of the starting crude plant material to Powdered Extract is between 2:1 and 8:1. It contains NLT 4.0% and NMT 5.0% of total phenols, calculated as the sum of caftaric acid (C13H12O9), chicoric acid (C22H18O12), chlorogenic acid (C16H18O9), and echinacoside (C35H46O20), on the dried basis.
• A. Presence of Echniacoside and Absence of Dicaffeoylquinic Acids (cynarin(e))
Standard solution A: 100 mg/mL of USP Powdered Echinacea pallida Extract RS in methanol
Standard solution B: 1 mg/mL of 1,3-dicaffeoylquinic acid in methanol
Sample solution: Dissolve 1.0 g of Powdered Extract in 10 mL of methanol. Allow to settle before use.
Adsorbent: 0.25-mm layer of chromatographic silica gel mixture, typically 20 cm long (TLC plates)
Application volume: 10 µL
Developing solvent system: Ethyl acetate, formic acid, and water (17:2:1)
Spray reagent A: 10 mg/mL of diphenylborinic acid, ethanolamine ester in methanol
Spray reagent B: 50 mg/mL of polyethylene glycol 4000 in alcohol
Samples: Standard solution A, Standard solution B, and Sample solution
Develop the chromatograms until the solvent front has moved NLT 12 cm, and dry the plate in a current of air. Spray the plate with Spray reagent A followed by Spray reagent B, and examine the plate under UV light at 365 nm.
Acceptance criteria: The chromatogram obtained from the Sample solution shows a yellowish zone at an RF value of 0.14 characteristic of echinacoside (absent or only traces present in Echinacea purpurea) that corresponds in color and RF value to that in the chromatogram of Standard solution A, and does not show a zone characteristic of 1,3-dicaffeoylquinic acid (present in Echinacea angustifolia) corresponding in color and RF value to that in the chromatogram of Standard solution B. Other colored zones of varying intensities may be observed in the chromatogram of the Sample solution.
• B. The retention time of the major peak of the Sample solution corresponds to that of the echinacoside peak of Standard solution A, as obtained in the test for Content of Total Phenols.
• Content of Total Phenols
Solution A: Phosphoric acid (0.1 in 100)
Solution B: Acetonitrile
Mobile phase: See Table 1.
Solvent: Alcohol and water (7:3)
Standard solution A: Dissolve USP Powdered Echinacea pallida Extract RS in Solvent, by shaking and heating in a water bath. Dilute with Solvent to obtain a solution having a known concentration of 1 mg/mL. Pass through a membrane filter having a 0.45-µm or finer pore size.
Standard solution B: 40 µg/mL of USP Chlorogenic Acid RS in Solvent
Sample solution: Transfer about 60 mg of Powdered Extract, accurately weighed, to an appropriate round-bottom flask equipped with a condenser. Add 25.0 mL of Solvent, and heat under reflux while shaking by mechanical means for 15 min. Centrifuge, or pass through a membrane filter having a 0.45-µm or finer pore size.
Detector: UV 330 nm
Column: 4.6-mm × 25-cm; 5-µm packing L1
Column temperature: 35
Flow rate: 1.5 mL/min
Injection size: 5 µL
Samples: Standard solution A and Standard solution B
Chromatographic similarity: The chromatogram of Standard solution A is similar to the Reference Chromatogram for total phenols provided with USP Powdered Echinacea pallida Extract RS.
Capacity factor (k¢): NLT 3.0 for the chlorogenic acid peak, Standard solution B
Tailing factor: NMT 2.0 for the chlorogenic acid peak, Standard solution B
Relative standard deviation: NMT 2.5% for the chlorogenic acid peak in repeated injections, Standard solution B
Samples: Sample solution, Standard solution A, and Standard solution B
Identify the relevant analytes in the chromatogram obtained from the Sample solution by comparison with the chromatogram obtained from Standard solution A. Measure the areas for the relevant peaks.
Separately calculate the percentage of caftaric acid (C13H12O9), chicoric acid (C22H18O12), chlorogenic acid (C16H18O9), and echinacoside (C35H46O20) in the portion of Powdered Echinacea pallida Extract taken:
Result = (rU/rS) × (CS/CU) × F × 100
Calculate the percentage of total phenols in the portion of Powdered Echinacea pallida Extract taken by adding the individual percentages calculated.
Acceptance criteria: NLT 4.0% and NMT 5.0% of total phenols on the dried basis
• Heavy Metals Method II 231: NMT 20 ppm
• Microbial Enumeration Tests 2021: The total bacterial count does not exceed 104 cfu/g and the total combined molds and yeasts count does not exceed 103 cfu/g.
• Microbiological Procedures for Absence of Specified Microorganisms 2022: Meets the requirements of the tests for absence of Salmonella species, and Escherichia coli
• Other Requirements: It meets the requirements for Botanical Extracts 565, Residual Solvents and Pesticide Residues.
• Loss on Drying 731: Dry 1 g at 105 for 2 h: it loses NMT 5.0%.
• Packaging and Storage: Preserve in tight, light-resistant containers, and store in a cool place.
• Labeling: The label states the Latin binomial and, following the official name, the parts of the plant from which the article was prepared. The label bears a statement indicating that Echinacea pallida may cause rare allergic reactions, rashes, or aggravate asthma. It meets the requirements for Botanical Extracts 565, Labeling.
• USP Reference Standards 11
USP Powdered Echinacea pallida Extract RS
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USP35NF30 Page 1274Pharmacopeial Forum: Volume No. 30(2) Page 556