Powdered Black Cohosh
DEFINITION
Powdered Black Cohosh is Black Cohosh reduced to a powder or a very fine powder. It contains NLT 0.4% of triterpene glycosides, calculated as 23-epi-26-deoxyactein (C37H56O10) on the dried basis.
IDENTIFICATION
•  A. Thin-Layer Chromatographic Identification Test
Standard solution A:  100 mg/mL of USP Powdered Black Cohosh Extract RS in methanol
Standard solution B:  1 mg/mL each of USP Actein RS, USP 23-epi-26-Deoxyactein RS, and isoferulic acid in methanol
Sample solution:  Transfer 5 g of Powdered Black Cohosh to a screw-capped centrifuge tube, add 10 mL of a mixture of alcohol and water (7:3), and heat on a steam bath for 10 min. Centrifuge, and use the clear supernatant.
Adsorbent:  Chromatographic silica gel mixture with an average particle size of 10–15 µm (TLC plates)
Application volume:  10 µL
Developing solvent system:  Use the upper phase of a mixture of butyl alcohol, glacial acetic acid, and water (5:1:4).
Spray reagent:  Methanol, glacial acetic acid, sulfuric acid, and p-anisaldehyde (85:10:5:0.5). [Note—Store in a refrigerator. The reagent is colorless; discard if color appears. ]
Analysis 
Samples:  Standard solution A, Standard solution B, and Sample solution
Develop the chromatograms until the solvent front has moved about 15 cm, and dry the plate with the aid of a current of air.
Acceptance criteria:  Examine the plate under UV light at 365 nm. The chromatogram of the Sample solution exhibits main zones similar in position and color to the main zones of Standard solution A. In the upper third of the plate, the Sample solution exhibits a blue fluorescent zone at the level of the zone due to isoferulic acid of Standard solution B. Spray the plate with Spray reagent, heat at 100 for 5 min, and examine in daylight. The Sample solution exhibits main zones similar in position and color to the main zones of Standard solution A. Standard solution B exhibits red-violet zones due to actein and 23-epi-26-deoxyactein. The Sample solution exhibits several greenish-brown spots in the lower third of the plate and several violet zones above; two of these violet zones occur at RF values similar to those due to actein and 23-epi-26-deoxyactein of Standard solution B.
•  B. Thin-Layer Chromatographic Identification Test
Standard solution A:  0.5 mL of Standard solution A prepared in Identification test A, diluted with methanol to 2 mL
Standard solution B:  1.0 mL of Standard solution B prepared in Identification test A, diluted with methanol to 5 mL
Sample solution:  Transfer 0.5 g of Powdered Black Cohosh to a screw-capped tube, add 5 mL of methanol, sonicate for 10 min, and filter into a 10-mL volumetric flask. Wash the residue on the filter paper four times, using 1 mL of methanol for each washing; add the washings to the volumetric flask; and dilute with methanol to volume.
Adsorbent:  Chromatographic silica gel mixture with an average particle size of 5 µm (HPTLC plates)
Application volume:  2 µL as an 8-mm band
Developing solvent system:  Toluene, ethyl formate, and formic acid (5:3:2)
Spray reagent:  Proceed as directed for Identification test A.
Analysis 
Samples:  Standard solution A, Standard solution B, and Sample solution
Develop the chromatograms until the solvent front has moved about two-thirds of the length of the plate, and dry the plate with the aid of a current of air. Spray the plate with Spray reagent, heat at 100 for 5 min, and examine in daylight.
Acceptance criteria:  The Sample solution exhibits main zones similar in position and color to the main zones of Standard solution A. Standard solution B exhibits red-violet zones due to actein and 23-epi-26-deoxyactein at RF values of about 0.5 and 0.4, respectively. The Sample solution exhibits zones similar in color and RF values to those due to actein and 23-epi-26-deoxyactein of Standard solution B.
•  C. The Sample solution exhibits peaks for cimiracemoside A, 26-deoxycimicifugoside, (26S)-actein, 23-epi-26-deoxyactein, cimigenol–arabinoside, and cimigenol–xyloside at retention times corresponding to those compounds in the Standard solution, as obtained in the test for Content of Triterpene Glycosides. The ratio of the peak areas of cimigenol–arabinoside to cimigenol–xyloside is NLT 0.4 (distinction from Cimicifuga foetida).
COMPOSITION
•  Content of Triterpene Glycosides
Standard solution:  Dissolve a quantity of USP Powdered Black Cohosh Extract RS in methanol with shaking for 1 min, and dilute with methanol to obtain a solution having a known concentration of 30 mg/mL. Pass through a membrane filter of 0.45-µm or finer pore size.
23-epi-26-Deoxyactein standard solutions:  Dissolve USP 23-epi-26-Deoxyactein RS in methanol with shaking for 1 min. Dilute quantitatively, and stepwise if necessary, to obtain solutions having known concentrations of 500, 100, 50, 25, and 12.5 µg/mL. Pass through a membrane filter of 0.45-µm or finer pore size.
System suitability solution:  0.1 mg/mL each of USP Actein RS and USP 23-epi-26-Deoxyactein RS in methanol
Sample solution:  Accurately weigh about 750 mg of Powdered Black Cohosh, and place in a 20-mL polytef-capped centrifuge tube. Pipet 15 mL of methanol, sonicate for 30 min, centrifuge, and transfer the supernatant to an evaporation flask. Repeat the extraction twice. Evaporate the combined extracts under vacuum at 45–50. Dissolve the residue in methanol, and quantitatively transfer to a 10-mL volumetric flask. Dilute with methanol to volume, and pass through a membrane filter of 0.45-µm or finer pore size.
Solution A:  0.05% trifluoroacetic acid in water
Solution B:  Acetonitrile
Mobile phase:  See Table 1 below.
Table 1
Time
(min)
Water
(%)
Solution A
(%)
Solution B
(%)
0 0 80 20
8 0 80 20
15 68 0 32
55 36 0 64
65 5 0 95
70 5 0 95
85 0 80 20
Chromatographic system  
Mode:  LC
Detector:  Evaporative light-scattering
[Note—The detector is set up according to the manufacturer's instruction in order to achieve a signal-to-noise ratio of NLT 10 for the 12.5-µg/mL 23-epi-26-Deoxyactein standard solution. ]
Column:  4.6-mm × 25-cm; 5-µm packing L1
Column temperature:  35
Flow rate:  1.6 mL/min
Injection size:  20 µL
System suitability 
Samples:  System suitability solution, Standard solution, and the 100-µg/mL 23-epi-26-Deoxyactein standard solution
Suitability requirements 
Chromatogram similarity:  The chromatogram of the Standard solution is similar to the Reference Chromatogram provided with the lot of USP Powdered Black Cohosh Extract RS being used.
Resolution:  NLT 1.0 between the (26S)-actein and the 23-epi-26-deoxyactein peaks, System suitability solution
Tailing factor:  NMT 2.0 for the 23-epi-26-deoxyactein peak, 100-µg/mL 23-epi-26-Deoxyactein standard solution
Relative standard deviation:  NMT 2.0% of the logarithm of the area responses for replicate injections, 100-µg/mL 23-epi-26-Deoxyactein standard solution
Analysis 
Samples:  System suitability solution, Standard solution, 23-epi-26-Deoxyactein standard solutions, and Sample solution
Using the chromatogram of the Standard solution and the Reference Chromatogram provided with the lot of USP Powdered Black Cohosh Extract RS, identify the retention times of the peaks corresponding to the triterpene glycosides. The approximate relative retention times of the triterpene glycosides are provided in Table 2.
Table 2
Name Relative
Retention
Time
Cimicifugoside H-1 0.61
Cimiracemoside A 0.78
(26R)-Actein 0.94
26-Deoxycimicifugoside 0.96
(26S)-Actein 0.98
23-epi-26-Deoxyactein 1.00
Acetyl-shengmanol–xyloside 1.03
Cimigenol–arabinoside 1.08
Cimigenol–xyloside (cimicifugoside) 1.13
26-Deoxyactein 1.22
25-Acetyl-cimigenol–arabinoside 1.60
(24S)-25-Acetyl-cimigenol–xyloside 1.64
25-O-Methyl-cimigenol–arabinoside 1.90
25-O-Methyl-cimigenol–xyloside 1.93
Plot the logarithms of the peak area responses versus the logarithms of the concentrations, in µg/mL, of the 23-epi-26-Deoxyactein standard solution, and determine the regression line using a least-squares analysis. The correlation coefficient for the regression line is NLT 0.995. From the graphs so obtained, determine the concentration, C, in µg/mL, of the relevant analyte in the Sample solution. Separately calculate the percentages of cimicifugoside H-1, cimiracemoside A, (26R)-actein, 26-deoxycimicifugoside, (26S)-actein, 23-epi-26-deoxyactein, acetyl-shengmanol–xyloside, cimigenol–arabinoside, cimigenol–xyloside (cimicifugoside), 26-deoxyactein, 25-acetyl-cimigenol–arabinoside, (24S)-25-acetyl-cimigenol–xyloside, 25-O-methyl-cimigenol–arabinoside, and 25-O-methyl-cimigenol–xyloside as 23-epi-26-deoxyactein (C37H56O10) in the portion of Powdered Black Cohosh taken:
Result = (V × C)/(F × W) × 100
V== volume of the Sample solution (mL)
C== concentration of the relevant analyte in the Sample solution (µg/mL)
F== factor to convert mg to µg, 1000 µg/mg
W== weight of Powdered Black Cohosh taken to prepare the Sample solution (mg)
Calculate the percentage of the labeled amount of triterpene glycosides in the portion of Powdered Black Cohosh taken by adding all of the percentages calculated for the individual analytes.
Acceptance criteria:  NLT 0.4% on the dried basis
CONTAMINANTS
•  Heavy Metals 231: NMT 10 ppm
•  Microbial Enumeration Tests 2021: It meets the requirements of the tests for absence of Salmonella species and Escherichia coli. The total aerobic microbial 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.
SPECIFIC TESTS
•  Botanic Characteristics: The material is a light to dark brown powder, is odorless or has a slight odor, and has an acrid and bitter taste. It shows numerous starch granules with concentric striations, simple or compound. The individual granules are spherical or more or less polygonal and are between 3 and 15 µm in diameter, each with a somewhat central slit-shaped hilum. Vessels with bordered pits occur, as do lignified fibers. Reddish to brown fragments of suberized epidermis with more or less tabular cells occur.
•  Articles of Botanical Origin, Alcohol-Soluble Extractives, Method 2 561: NLT 8.0%, using a mixture of alcohol and water (1:1) instead of alcohol
•  Loss on Drying 731: Dry a sample at 105 for 2 h: it loses NMT 12.0% of its weight.
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in well-closed, light-resistant containers, and protect from moisture.
•  Labeling: The label states the Latin binomial and, following the official name, the parts of the plant from which the article was derived. Dosage forms prepared with this article should bear the following statement: Discontinue use and consult a healthcare practitioner if you have a liver disorder or develop symptoms of liver trouble, such as abdominal pain, dark urine, or jaundice.
•  USP Reference Standards 11
USP Actein RS Click to View Structure
USP Powdered Black Cohosh Extract RS
USP 23-epi-26-Deoxyactein RS
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