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Powdered Stinging Nettle Extract
» Powdered Stinging Nettle Extract is prepared from comminuted Stinging Nettle with 60 percent alcohol or other suitable solvents. It contains not less than 5.0 percent of total amino acids, not less than 0.1 percent of -sitosterol (C29H50O), and not less than 30 µg per g of scopoletin (C10H8O4). The ratio of the starting crude plant material to Powdered Extract is 10:1.
Packaging and storage— Preserve in tight containers, protected from light. Store at controlled room temperature.
Labeling— The label states the official name of the article, the Latin binomial, and, following the official name, the part of the plant from which the article was prepared. Label it to indicate the content of total amino acids, -sitosterol, scopoletin, the extracting solvent used for preparation, and the ratio of the starting crude plant material to Powdered Extract.
Identification—
A: Thin-Layer Chromatographic Identification Test 201—
Adsorbent, Standard solution, Application volume, Developing solvent system, and Procedure— Proceed as directed for the test for Identification under Stinging Nettle.
Test solution— Dissolve 0.6 g of Powdered Extract, accurately weighed, in a mixture of toluene, ethyl acetate, and methanol (7:2:1), filter, and dry under reduced pressure at a temperature below 40. Dissolve the residue in 2.0 mL of the toluene, ethyl acetate, and methanol mixture.
B: The retention time of -sitosterol in the chromatogram of the Test solution corresponds to that in the chromatogram of the Standard solution, as obtained in the test for Content of -sitosterol.
C: The retention time of scopoletin in the chromatogram of the Test solution corresponds to that in the chromatogram of the Standard solution, as obtained in the test for Content of scopoletin.
Microbial enumeration 2021— The total aerobic microbial count does not exceed 103 cfu per g, and the total combined molds and yeasts count does not exceed 102 cfu per g. It meets the requirements of the tests for absence of Salmonella species and Escherichia coli.
Loss on drying 731— Dry about 1.0 g of Powdered Extract, accurately weighed, at 105 for 2 hours: it loses not more than 8.0% of its weight.
Total ash 561: not more than 20.0%.
Pesticide residues 561: meets the requirements.
Alcohol content, Method II 611 (if present): not more than 1.0%.
Content of total amino acids—
pH 5.5 Acetate buffer, Reagent solution, and Standard solution— Proceed as directed for Content of total amino acids under Stinging Nettle.
Test solution— Dissolve 50 mg of Powdered Extract, accurately weighed, in 80 mL of water, shake for 10 minutes, dilute with water to 100 mL, and filter.
Procedure— Proceed as directed for Content of total amino acids under Stinging Nettle, except to calculate the percentage of total amino acids taken by the formula:
2000(AU / AS)(WS / WU),
in which WU is the weight, in mg, of the Powdered Extract in the Test solution; and the other terms are as defined therein: not less than 5.0% of total amino acids is found.
Content of -sitosterol—
Derivatizing reagent, Internal standard solution, Standard solution, and Chromatographic system— Proceed as directed for Content of -sitosterol under Stinging Nettle.
Test solution— Transfer 20.0 g of Powdered Extract, accurately weighed, to a Soxhlet apparatus, treat with chloroform, and extract for 6 hours. The volume of chloroform used is at least twice the volume of the thimble with an appropriate-size flask. Dry the solvent under reduced pressure, add 1.0 mL of Internal standard solution, and dilute with chloroform to 10 mL. Transfer 0.5 mL of this solution to a 10-mL round-bottomed flask, dry the solvent under reduced pressure, and add 0.5 mL of Derivatizing reagent.
Procedure— Proceed as directed for Content of -sitosterol under Stinging Nettle, except to calculate the percentage of -sitosterol in the portion of Powdered Extract taken by the formula:
100(RU / RS)(CS / CU),
in which CU is the concentration, in mg per mL, of Powdered Extract in the Test solution; and the other terms are as defined therein: not less than 0.1% of -sitosterol is found.
Content of scopoletin—
Solution A, Solution B, Mobile phase, Standard solution, and Chromatographic system— Proceed as directed for Content of scopoletin under Stinging Nettle.
Test solution— Dissolve 200 mg of Powdered Extract, accurately weighed, in 25 mL of methanol, place in an ultrasonic bath for 25 minutes, and centrifuge. Transfer 0.5 mL of this solution to a 10-mL volumetric flask, and dilute with methanol to volume.
Procedure— Proceed as directed for Content of scopoletin under Stinging Nettle, except to calculate the content of scopoletin (C10H8O4) in the portion of Powdered Extract taken by the formula:
10,000(rU / rS)(CS / CU),
in which CU is the concentration, in mg per mL of Powdered Extract in the Test solution; and the other terms are as defined therein: not less than 30 µg per g of scopoletin is found.
Residual solvents 467: meets the requirements.
(Official January 1, 2007)
Auxiliary Information— Staff Liaison : Maged H. Sharaf, Ph.D., Senior Scientist
Expert Committee : (DSB05) Dietary Supplements - Botanicals
USP29–NF24 Page 2369
Pharmacopeial Forum : Volume No. 29(4) Page 1289
Phone Number : 1-301-816-8318