Powdered American Ginseng
DEFINITION
Powdered American Ginseng is American Ginseng reduced to a fine or a very fine powder. It contains NLT 4.0% of total ginsenosides, calculated on the dried basis.
IDENTIFICATION
•  A. Thin-Layer Chromatographic Identification Test
Standard solution A:  20 mg/mL of USP Powdered American Ginseng Extract RS in methanol
Standard solution B:  20 mg/mL of USP Powdered Asian Ginseng Extract RS in methanol
Sample solution:  Transfer about 1.0 g of Powdered American Ginseng to a 25-mL flask fitted with a reflux condenser. Add 10.0 mL of a mixture of methanol and water (7:13), and heat under reflux for 15 min. Cool, filter, and dilute the filtrate with methanol to 10.0 mL.
Adsorbent:  0.25-mm layer of chromatographic silica gel, typically 20 cm long (TLC plates)
Application volume:  20 µL
Developing solvent system A:  Chloroform, methanol, and water (13:7:2). Use the lower phase.
Developing solvent system B:  Butyl alcohol, ethyl acetate, and water (4:1:5). Use the upper phase.
Spray reagent:  Dissolve 0.5 mL of anisaldehyde in 10 mL of glacial acetic acid, add 85 mL of methanol, mix, and carefully add 5 mL of sulfuric acid.
Analysis 
Samples:  Standard solution A, Standard solution B, and Sample solution
Develop in a chamber containing Developing solvent system A until the solvent front has moved 10.5 cm from the origin. Remove the plates, and allow to dry. Turn the plates 90, and develop in a chamber containing Developing solvent system B until the solvent front has moved 10.5 cm from the origin. Remove the plates, and allow to dry. Spray with Spray reagent. Heat the plates at 105–110 for 10 min, and examine.
Suitability requirements:  The order, from top to bottom, of ginsenosides on the chromatographic plates is: Rg2 (on left) and Rg1 (on right), Rf, Re, Rd, Rc, Rb2 (on left) and Rb1 (on right), and Ro. Ginsenosides Rg2, Rg1, Rf, Re, and Rd are found on the upper half of the plates; the remaining ginsenosides are found on the lower half after chromatographing with Developing solvent system B. Standard solution A does not exhibit a spot for ginsenoside Rf. Standard solution B exhibits a spot for ginsenoside Rf.
Acceptance criteria:  The spots from the Sample solution correspond to those from Standard solution A.
•  B. The retention times of the peaks for ginsenosides Rg1, Re, Rb1, Rb2, Rc2, and Rd of the Sample solution correspond to those of Standard solution A, as obtained in the test for Content of Ginsenosides. The ratio of the peak responses for ginsenosides Rb2 to Rb1 is less than 0.4, and the ratio of the peak responses for ginsenosides Rg1 to Rb1 is less than 0.3. The chromatogram shows no significant peak at the retention time corresponding to that for ginsenoside Rf of Standard solution B, as obtained in the test for Content of Ginsenosides.
COMPOSITION
•  Content of Ginsenosides
Solution A:  Water
Solution B:  Acetonitrile and water (4:1)
Mobile phase:  See Table 1.
Table 1
Time
(min)
Solution A
(%)
Solution B
(%)
0 76 24
12 76 24
28 65 35
51.5 56.5 43.5
52.5 0 100
64.5 76 24
77 76 24
Diluent:  Alcohol and water (4:6)
Standard solution A:  Transfer a quantity of USP Powdered American Ginseng Extract RS, equivalent to about 2 mg of ginsenoside Rb1, to a suitable container, and dissolve in 10.0 mL of Diluent.
Standard solution B:  Transfer a quantity of USP Powdered Asian Ginseng Extract RS, equivalent to about 2 mg of ginsenoside Rg1, to a suitable container, and dissolve in 10.0 mL of Diluent.
Sample solution:  Transfer about 1.0 g of Powdered American Ginseng, accurately weighed, to a 100-mL, round-bottom flask fitted with a reflux condenser. Add 50 mL of Diluent and a few grains of pumice, boil on a water bath under reflux for 1 h, cool, and filter. Wash the flask and the residue with 20 mL of Diluent, and pass through the same filter. Combine the filtrates, and evaporate in a rotary evaporator at 50 to dryness. Dissolve the residue in 10.0 mL of Diluent.
Chromatographic system 
Mode:  LC
Detector:  UV 203 nm
Analytical column:  4.6-mm × 15-cm; 3-µm packing L1
Guard column:  4.6-mm × 2.0-cm; packing L1
Column temperature:  25
Flow rate:  1.5 mL/min
Injection size:  10 µL
System suitability 
Sample:  Standard solution B
Suitability requirements 
Chromatogram similarity:  The chromatogram is similar to the Reference Chromatogram provided with the lot of USP Powdered Asian Ginseng Extract RS being used.
Relative standard deviation:  NMT 2.0%, determined for the sum of the peak areas for the 6 major ginsenosides, in replicate injections
Analysis 
Samples:  Standard solution A, Standard solution B, and Sample solution
Identify ginsenosides Rg1, Re, Rb1, Rc, Rb2, and Rd in the Standard solutions and the Sample solution by comparing the chromatograms with the Reference Chromatogram provided with USP Powdered American Ginseng Extract RS, and measure the peak responses.
Calculate the percentages of individual ginsenosides in the portion of Powdered American Ginseng taken:
Result = (rU/rS) × CS × (V/W) × 100
rU== peak response of ginsenoside Rg1, Re, Rb1, Rc, Rb2, or Rd from the Sample solution
rS== peak response of ginsenoside Rg1, Re, Rb1, Rc, Rb2, or Rd from the appropriate Standard solution
CS== concentration of ginsenoside Rg1, Re, Rb1, Rc, Rb2, or Rd in the appropriate Standard solution (mg/mL)
V== volume of the Sample solution (mL)
W== weight of Powdered American Ginseng taken to prepare the Sample solution (mg)
Calculate the percentage of total ginsenosides in the portion of Powdered American Ginseng taken by adding the individual percentages.
Acceptance criteria:  NLT 4.0% of total ginsenosides on the dried basis
CONTAMINANTS
•  Heavy Metals, Method III 231: NMT 20 ppm
SPECIFIC TESTS
•  Botanic Characteristics: Pale yellowish-brown powder with a slightly aromatic odor. Oval parenchymatous cells packed with starch granules and occasional druse crystals of calcium oxalate. Yellowish-brown secretory vessels with yellowish-brown contents.
•  Loss on Drying 731: Dry 1 g of it, finely powdered, at 105 for 2 h: it loses NMT 10.0% of its weight.
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Store in tight containers, protected from light, moisture, and heat.
•  Labeling: The label states the Latin binomial and, following the official name, the parts of the plant contained in the article.
•  USP Reference Standards 11
USP Powdered American Ginseng Extract RS
USP Powdered Asian Ginseng Extract RS
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Maged H. Sharaf, Ph.D.
Principal Scientific Liaison
1-301-816-8318
(DS2010) Monographs - Dietary Supplements
Reference Standards RS Technical Services
1-301-816-8129
rstech@usp.org
USP35–NF30 Page 1176
Pharmacopeial Forum: Volume No. 30(2) Page 564