Powdered Stinging Nettle Extract
»Powdered Stinging Nettle Extract is prepared from comminuted Stinging Nettle with 60percent alcohol or other suitable solvents.It contains not less than 5.0percent of total amino acids,not less than 0.1percent of b-sitosterol (C29H50O),and not less than 30µg 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,b-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 á201ñ—
Adsorbent,Standard solution,Application volume,Developing solvent system,and Procedure— Proceed as directed for the test for Identificationunder Stinging Nettle.
Test solution— Dissolve 0.6g 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 2.0mLof the toluene,ethyl acetate,and methanol mixture.
B: The retention time of b-sitosterol in the chromatogram of the Test solutioncorresponds to that in the chromatogram of the Standard solution,as obtained in the test for Content of b-sitosterol.
C: The retention time of scopoletin in the chromatogram of the Test solutioncorresponds to that in the chromatogram of the Standard solution,as obtained in the test for Content of scopoletin.
Microbial enumeration á2021ñ— The total aerobic microbial count does not exceed 103cfu per g,and the total combined molds and yeasts count does not exceed 102cfu per g.It meets the requirements of the tests for absence of Salmonellaspecies and Escherichia coli.
Loss on drying á731ñ— Dry about 1.0g of Powdered Extract,accurately weighed,at 105for 2hours:it loses not more than 8.0%of its weight.
Total ash á561ñ: not more than 20.0%.
Pesticide residues á561ñ: meets the requirements.
Alcohol content,Method IIá611ñ(if present): not more than 1.0%.
Content of total amino acids—
pH5.5Acetate buffer,Reagent solution,and Standard solution— Proceed as directed for Content of total amino acidsunder Stinging Nettle.
Test solution— Dissolve 50mg of Powdered Extract,accurately weighed,in 80mLof water,shake for 10minutes,dilute with water to 100mL,and filter.
Procedure— Proceed as directed for Content of total amino acidsunder Stinging Nettle,except to calculate the percentage of total amino acids taken by the formula:
2000(AU/AS)(WS/WU),
in which WUis 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 b-sitosterol—
Derivatizing reagent,Internal standard solution,Standard solution,and Chromatographic system— Proceed as directed for Content of b-sitosterolunder Stinging Nettle.
Test solution— Transfer 20.0g of Powdered Extract,accurately weighed,to a Soxhlet apparatus,treat with chloroform,and extract for 6hours.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 1.0mLof Internal standard solution,and dilute with chloroform to 10mL.Transfer 0.5mLof this solution to a 10-mLround-bottomed flask,dry the solvent under reduced pressure,and add 0.5mLof Derivatizing reagent.
Procedure— Proceed as directed for Content of b-sitosterolunder Stinging Nettle,except to calculate the percentage of b-sitosterol in the portion of Powdered Extract taken by the formula:
100(RU/RS)(CS/CU),
in which CUis 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 b-sitosterol is found.
Content of scopoletin—
Solution A,Solution B,Mobile phase,Standard solution,and Chromatographic system— Proceed as directed for Content of scopoletinunder Stinging Nettle.
Test solution— Dissolve 200mg of Powdered Extract,accurately weighed,in 25mLof methanol,place in an ultrasonic bath for 25minutes,and centrifuge.Transfer 0.5mLof this solution to a 10-mLvolumetric flask,and dilute with methanol to volume.
Procedure— Proceed as directed for Content of scopoletinunder 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 CUis the concentration,in mg per mLof Powdered Extract in the Test solution;and the other terms are as defined therein:not less than 30µg per g of scopoletin is found.
Auxiliary Information— Staff Liaison:Gabriel I.Giancaspro,Ph.D.,Senior Scientist and Latin American Specialist
Expert Committee:(DSB)Dietary Supplements:Botanicals
USP28–NF23Page 2123
Pharmacopeial Forum:Volume No.29(4)Page 1289
Phone Number:1-301-816-8343