Powdered Rhodiola rosea
DEFINITION
Powdered Rhodiola rosea is Rhodiola rosea L. reduced to a powder or fine powder. It contains NLT 0.3% of phenylpropanoid glycosides, calculated as the sum of rosarin, rosavin, and rosin, and NLT 0.08% of salidroside, both calculated on the dried basis.
IDENTIFICATION
•  A. Powdered Rhodiola rosea meets the requirements under Specific Tests, Botanic Characteristics.
•  B. Thin-Layer Chromatography
Standard solution A:  1.0 mg/mL of USP Rosavin RS in methanol
Standard solution B:  50 mg/mL of USP Rhodiola rosea Root and Rhizome Dry Extract RS in methanol. Sonicate for 10 min, centrifuge, and use the supernatant.
Sample solution:  Sonicate for 10 min about 0.5 g of Powdered Rhodiola rosea in 5 mL of methanol, centrifuge, and use the supernatant.
Chromatographic system 
Adsorbent:  Chromatographic silica gel with an average particle size of 5 µm (HPTLC plates)
Application volume:  3 µL of Standard solution A and 5 µL each of Standard solution B and Sample solution; as 8-mm bands
Relative humidity:  Condition the plate to a relative humidity of about 33% using a suitable device.
Developing solvent system:  A mixture of ethyl acetate, methanol, water, and formic acid (77:13:10:2)
Developing distance:  6 cm
Derivatization reagent:  Dissolve 1 g of diphenylamine in 40 mL of acetone, add 1 mL of aniline, and mix. Carefully add 7.5 mL of phosphoric acid, and mix.
Analysis 
Samples:  Standard solution A, Standard solution B, and Sample solution
Apply the samples as bands to a suitable high performance thin-layer chromatographic plate, and dry in air. Develop the chromatograms in a saturated chamber, remove the plate from the chamber, and dry in air. Derivatize the plate with Derivatization reagent, heat at 120 for 5 min, and examine under visible light.
System suitability:  The chromatogram of Standard solution B exhibits, in the lower half, three gray bands and two brownish bands, one above and the other below the gray bands; the most intense band in the chromatogram is the brownish band with an RF below the gray bands; the most intense gray band is the lower band at an RF corresponding to the band due to rosavin in the chromatogram of Standard solution A; the upper gray band due to rosarin is less intense.
Acceptance criteria:  The chromatogram of the Sample solution exhibits a gray band corresponding to the band due to rosavin in the chromatogram of Standard solution A, and the following bands corresponding to similar bands in the chromatogram of Standard solution B: two additional gray bands and two brownish bands, one above and the other below the gray bands; the most intense band in the chromatogram is the brownish band with an RF below the gray bands; the most intense gray band is the lower band due to rosavin.
•  C. HPLC
Analysis:  Proceed as directed in the test for Content of Phenylpropenoid Glycosides and Salidroside.
Acceptance criteria:  The chromatogram of the Sample solution exhibits peaks at the retention times corresponding to the peaks due to salidroside, tyrosol, rosarin, rosavin, rosin, and rosiridin in the chromatogram of Standard solution C. The ratio of the content of the phenylpropenoid glycosides, rosarin, rosavin, and rosin, to the content of salidroside is about 3:1.
COMPOSITION
•  Content of Phenylpropenoid Glycosides and Salidroside
Solution A:  Water
Solution B:  Acetonitrile
Mobile phase:  See Table 1.
Table 1
Time
(min)
Solution A
(%)
Solution B
(%)
0 94 6
6 83 17
7 80.3 19.7
9 80.3 19.7
10 0 100
12 94 6
17 94 6
Solvent:  75% methanol in water
Standard solution A:  1.0 mg/mL of USP Rosavin RS in methanol
Standard solution B:  0.3 mg/mL of USP Salidroside RS in methanol
Standard solution C:  4.0 mg/mL of USP Rhodiola rosea Root and Rhizome Dry Extract RS in methanol. Sonicate to dissolve, if necessary. Before injection, pass through a membrane filter of 0.45-µm or finer pore size.
Sample solution:  Transfer about 5.0 g of Powdered Rhodiola rosea, accurately weighed, to a 25-mL flask. Add 7 mL of Solvent, sonicate for 15 min, and filter into a 10-mL volumetric flask. Wash the residue on the filter paper twice using 1 mL of Solvent each, add the washings to the volumetric flask, dilute with Solvent to volume, and mix. Before injection, pass through a membrane filter of 0.45-µm or finer pore size, discarding the first few mL of filtrate.
Chromatographic system 
(See Chromatography 621, System Suitability.)
Mode:  LC
Detector:  UV 205 nm
Column:  3.0-mm × 10-cm; 2.5-µm packing L1
Column temperature:  40 ± 1
Flow rate:  1.0 mL/min
Injection volume:  1 µL
System suitability 
Samples:  Standard solution A and Standard solution C
Suitability requirements 
Chromatogram similarity:  The chromatogram obtained from Standard solution C is similar to the reference chromatogram provided with the lot of USP Rhodiola rosea Root and Rhizome Dry Extract RS being used.
Resolution:  NLT 1.5 between the rosarin and rosavin peaks, Standard solution C
Relative standard deviation:  NMT 2% determined from the rosavin peak in repeated injections, Standard solution A
Analysis 
Samples:  Standard solution A, Standard solution B, Standard solution C, and Sample solution
Using the chromatograms of Standard solution A, Standard solution B, Standard solution C, and the reference chromatogram provided with the lot of USP Rhodiola rosea Root and Rhizome Dry Extract RS being used, identify the retention time of the peaks corresponding to salidroside, tyrosol, rosarin, rosavin, rosin, and rosiridin from the Sample solution.
Separately calculate the percentages of rosarin, rosavin, and rosin as rosavin in the portion of Powdered Rhodiola rosea taken:
Result = (rU/rS) × CS × (V/W) × 100

rU== peak area of the relevant analyte from the Sample solution
rS== peak area of rosavin from Standard solution A
CS== concentration of rosavin in Standard solution A (mg/mL)
V== volume of Sample solution (mL)
W== weight of Powdered Rhodiola rosea taken to prepare the Sample solution (mg)
Calculate the percentage of phenylpropenoid glycosides as the sum of the percentages of rosarin, rosavin, and rosin.
Calculate the percentage of salidroside in the portion of Powdered Rhodiola rosea taken:
Result = (rU/rS) × CS × (V/W) × 100

rU== peak area of salidroside in the Sample solution
rS== peak area of salidroside in Standard solution B
CS== concentration of salidroside in Standard solution B (mg/mL)
V== volume of the Sample solution (mL)
W== weight of Powdered Rhodiola rosea taken to prepare the Sample solution (g)
Acceptance criteria:  NLT 0.3% of phenylpropenoid glycosides and NLT 0.08% of salidroside, both calculated on the dried basis
CONTAMINANTS
•  Elemental Impurities—Procedures 233
Acceptance criteria 
Arsenic:  NMT 2.0 µg/g
Cadmium:  NMT 1.0 µg/g
Lead:  NMT 5.0 µg/g
Mercury:  NMT 1.0 µg/g
•  Microbial Enumeration Tests 2021: The total aerobic bacterial count does not exceed 105 cfu/g, the total combined molds and yeasts count does not exceed 103 cfu/g, and the bile-tolerant Gram-negative bacteria count does not exceed 103 cfu/g.
•  Absence of Specified Microorganisms 2022: Meets the requirements of the tests for absence of Salmonella species and Escherichia coli
SPECIFIC TESTS
•  Botanic Characteristics
Macroscopic:  Pinkish-brown or light brown in color
Microscopic  It shows fragments of cork cells, subrectangular or polygonal, containing yellowish-brown pigments, 10–150 µm in diameter; parenchymatous cells of cortex, subsquare or polygonal, containing reddish-brown pigments; stone cells, subrounded, subtriangular, subrectangular or irregular shape, some elongated, mostly 14–70 µm in diameter, up to 270 µm in length; fibers mostly in bundles, long fusiform in shape, ends oblique-sharp or blunt-round, with oblique or criss-cross striations, 10–60 µm in diameter; and reticulate and pitted vessels, up to 120 µm in diameter.
•  Loss on Drying 731
Sample:  1.0 g of Powdered Rhodiola rosea
Analysis:  Dry at 105 for 2 h.
Acceptance criteria:  NMT 12%
•  Articles of Botanical Origin, Total Ash 561
Sample:  2 g of Powdered Rhodiola rosea
Acceptance criteria:  NMT 12%
•  Articles of Botanical Origin, Acid-Insoluble Ash 561
Sample:  2–4 g of Powdered Rhodiola rosea
Acceptance criteria:  NMT 3%
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in well-closed containers, protected from light and moisture, and store at room temperature.
•  Labeling: The label states the Latin binomial and, following the official name, the parts of the plant from which the article was obtained.
•  USP Reference Standards 11
USP Rhodiola rosea Root and Rhizome Dry Extract RS
USP Rosavin RS Click to View Structure
USP Salidroside RS Click to View Structure
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Pharmacopeial Forum: Volume No. 39(3)