Rhodiola crenulata Root and Rhizome Powder

Rhodiola crenulata Root and Rhizome Powder

Proposed For Development Version 0.1

Rhodiola crenulata Root and Rhizome Powder




The article consists of the dried roots and rhizomes of Rhodiola crenulata (Hook. f. et Thomson) H. Ohba (Family Crassulaceae), collected after the scape wither in autumn, reduced to a fine or very fine powder. It contains NLT 1.0% of total phenylethanoids, calculated as the sum of salidroside (C14H20O7) and tyrosol (C8H10O2) on the dried basis; and NLT 0.6% of salidroside on the dried basis.



Rhodiola calliantha (H. Ohba) H. Ohba

Rhodiola cretinii (Hamet) H. Ohba

Rhodiola dumulosa (Franch.) S. H. Fu

Rhodiola heterodonta (HK. f. et Thoms.) A. Bor.

Rhodiola kirilowii (Regel) Maxim.

Rhodiola linearifolia A. Bor.

Rhodiola quadrifida (Pall.) Fisch. et Mey.

Rhodiola robusta (Praeg.) S. H. Fu

Rhodiola rosea L.

Rhodiola sachalinensis A. Bor.

Rhodiola serrata H. Ohba



Phenylethanoids: Salidroside and tyrosol

Benzoic acid: Gallic acid



• A. Botanical Characteristics

Macroscopic: Pinkish-brown or light reddish brown powder

Microscopic: Cork cell fragments subrectangular or polygonal, containing yellowish-brown pigments, 10–150 μm in diameter. Whorled vessels 6–58 μm in diameter. Fibers mostly in bundles, long fusiform with oblique or blunt-round ends, and oblique or criss-cross striations, 10–60 μm in diameter. Parenchymatous cells square or irregular, 2–20 μm in diameter, containing the calcium oxalate crystal. Abundant simple starch grains rounded with indistinct umbilical and lamina, 2–10 μm in diameter.

• B. HPTLC (See High-Performance Thin-Layer Chromatography Procedure for Identification of Articles of Botanical Origin <203>.)

Standard solution: 2.0 mg/mL of USP Salidroside RS, and 1.8 mg/mL of USP Tyrosol RS in methanol

Sample solution: Sonicate 1.0 g of Rhodiola crenulata Root and Rhizome Powder in 10 mL of 60% methanol for 30 min, centrifuge, and use the supernatant.

Chromatographic system

Adsorbent: Chromatographic silica gel F254 with an average particle size of 5 µm

Application volume: 5 µL, as 8-mm bands

Relative humidity: Condition the plate to a relative humidity of about 33% using a suitable device.

Developing solvent system: The lower layer solution of a mixture of dichloromethane, methanol, water, and formic acid (12: 4: 1: 0.5).

Developing distance: 6 cm


Samples: Standard solution and Sample solution

Apply the Samples as bands to a suitable HPTLC plate and dry in air. Develop in a saturated chamber, remove the plate from the chamber, and dry in air. Examine under UV light at 254 nm.

System suitability: Under UV light at 254 nm, the Standard solution exhibits a quenching band due to salidroside in the lower-third section, and a quenching band due to tyrosol in the middle-third section.

Acceptance criteria: Under UV light at 254 nm, the Sample solution exhibits two quenching bands corresponding in RF to the bands for salidroside and tyrosol in the Standard solution. The Sample solution exhibits additional quenching bands including one intense band above salidroside due to gallic acid, two clearly separated bands below salidroside, and a couple of faint bands close to the starting position.


Analysis: Proceed as directed in the Assay for Content of Phenylethanoids.

Acceptance criteria: The chromatogram of the Sample solution exhibits a peak with a retention time corresponding to the peak due to salidroside in the Standard solution, a peak due to tyrosol with lower intensity than the peak of salidroside, and a peak due to gallic acid. The peak area ratio of salidroside to tyrosol is not lower than 2.



• Content of Phenylethanoids

Solution A: 0.02% Phosphoric acid in water

Solution B: Methanol and acetonitrile (9:1)

Mobile phase: See Table 1.


Table 1


Solution A

Solution B


























Solvent: Methanol and water (6:4)

Standard solution: 0.3 mg/mL of USP Salidroside RS in methanol

Sample solution: Accurately transfer about 500 mg of Rhodiola crenulata Root and Rhizome Powder to a 50-mL conical flask and accurately add 15 mL of Solvent. Weigh the filled flask with a precision of ± 0.1 mg and then sonicate for 30 min. After cooling to room temperature, adjust to the initial weight by adding Solvent if needed. Before injection, pass through a membrane filter of 0.45-μm or finer pore size, and discard the first part of the filtrate.

Chromatographic system

(See Chromatography <621>, System Suitability.)

Mode: LC

Detector: UV 275 nm

Column: 4.6-mm × 25-cm; 5-μm packing L1 (similar to Merck Purospher STAR RP-18)

Column temperature: 25°

Flow rate: 1.0 mL/min

Injection volume: 10 µL

System suitability

Samples: Standard solution and Sample solution

Suitability requirements

Resolution: NLT 1.5 between salidroside and tyrosol peaks, Sample solution

Tailing factor: NMT 1.5 for the salidroside peak, Standard solution

Relative standard deviation: NMT 2.0% for salidroside, Standard solution


Samples: Standard solution and Sample solution

Using the chromatogram of the Standard solution and the relative retention times, identify the retention times of the peaks corresponding to gallic acid, salidroside, and tyrosol in the Sample solution. [Note—The approximate relative retention times for the peaks of gallic acid, salidroside, and tyrosol are 0.48, 1.00, and 1.05, respectively.]

Separately calculate the percentages of salidroside and tyrosol in the portion of Rhodiola crenulata Root and Rhizome Powder taken:


Result = (rU/rS) × CS × (V/W) × F × 100


rU   = peak area of the relevant analyte from the Sample solution

rS   = peak area of salidroside from the Standard solution

C = concentration of USP Salidroside RS in the Standard solution (mg/mL)

V    = volume of the Sample solution (mL)

W   = weight of Rhodiola crenulata Root and Rhizome Powder taken to prepare the Sample solution (mg)

F    = conversion factor for the analyte (1.00 for salidroside, 0.43 for tyrosol)


Calculate the content of total phenylethanoids as the sum of the percentages of salidroside and tyrosol.

Acceptance criteria

Salidroside: NLT 0.6% on the dried basis

Total phenylethanoids: NLT 1.0% on the dried basis



Articles of Botanical Origin <561>, Limits of Elemental Impurities: Meets the requirements

• Articles of Botanical Origin <561>, General Method for Pesticide Residues Analysis: Meets the requirements

• Microbial Enumeration Tests <61>: 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 does not exceed 103 cfu/g.

• Tests for Specified Microorganisms <62>: Meets the requirements of the tests for the absence of Salmonella species and Escherichia coli

• Articles of Botanical Origin <561>, Test for Aflatoxins: Meets the requirements



• Articles of Botanical Origin <561>, Alcohol-Soluble Extractives, Method 1: NLT 22.0%

• Loss on Drying <731>

Sample: 1.0 g of Rhodiola crenulata Root and Rhizome Powder

Analysis: Dry the Sample at 105° for 2 h.

Acceptance criteria: NMT 12.0%

• Articles of Botanical Origin <561>, Total Ash

Sample: 2.0 g of Rhodiola crenulata Root and Rhizome Powder

Acceptance criteria: NMT 6.0%

• Articles of Botanical Origin <561>, Acid-Insoluble Ash: NMT 2.0%



• Packaging and Storage: Preserve in well-closed containers, protected from light and moisture, and store at controlled room temperature.

• Labeling: The label states the Latin binomial and the part(s) of the plant contained in the article.

• USP Reference Standards <11>

USP Salidroside RS

USP Tyrosol RS


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Proposed For Comment Version 0.2