Powdered St. John's Wort Extract
» Powdered St. John's Wort Extract is prepared from comminuted St. John's Wort extracted with 80 percent methanol or other suitable solvents. It contains not less than 90.0 percent and not more than 110.0 percent of the labeled combined total of hypericin (C30H16O8) and pseudohypericin (C30H16O9) and not less than 90.0 percent and not more than 110.0 percent of hyperforin (C35H52O4).
Packaging and storage— Preserve in tight containers, protected from moisture and light.
Labeling— The label states the Latin binomial and, following the official name, the part of the plant from which the article was prepared. The label also indicates the content of hypericin, pseudohypericin, and hyperforin; the extracting solvent or solvent mixture used for preparation; and the ratio of the starting crude plant material to Powdered Extract. The label bears a statement indicating that “Rare cases of allergic reactions and photosensitivity have been reported with the use of St. John's Wort. St. John's Wort interacts with numerous medications. Check with your health care provider before using.”
USP Reference standards 11—
USP Oxybenzone RS.
USP Rutin RS.
USP Powdered St. John's Wort Extract RS.
Identification—
A: Thin-Layer Chromatographic Identification Test 201 (presence of hypericin, pseudohypericin, hyperoside, and rutin)—
Test solution— Transfer about 1 g of Powdered Extract, accurately weighed, to a 50-mL flask, add 20.0 mL of methanol, shake well, and use the clear supernatant.
Standard solution— Transfer about 0.25 g of USP Powdered St. John's Wort Extract RS, accurately weighed, to a 25-mL flask, add 5.0 mL of methanol, shake well, and use the clear supernatant.
Developing solvent system— Prepare a mixture of ethyl acetate, water, glacial acetic acid, and formic acid (10:2.6:1.1:1.1), and use the upper phase of the mixture. [note—Saturate the chromatographic chamber with the Developing solvent system vapors prior to the development of the chromatogram.]
Spray reagent A— Prepare a solution of diphenylborinic acid, ethanolamine ester in methanol containing 10 mg per mL.
Spray reagent B— Prepare a solution of polyethylene glycol 400 in alcohol containing 50 mg per mL.
Procedure— Develop the chromatogram until the solvent front has moved not less than 18 cm, and dry the plate with the aid of a current of air. Spray the plate with Spray reagent A, then with Spray reagent B, and examine the plate under UV light at 365 nm: the two red zones due to hypericin and pseudohypericin at RF values of about 0.85 and 0.80, respectively, in the chromatogram of the Test solution, correspond in color and RF value to those in the chromatogram of the Standard solution; the two yellow zones due to hyperoside and rutin at RF values of about 0.50 and 0.35, respectively, in the chromatogram of the Test solution, correspond in color and RF value to those in the chromatogram of the Standard solution. Other colored zones of varying intensities may be observed in the chromatogram of the Test solution.
B: Thin-Layer Chromatographic Identification Test 201 (presence of hyperforin)—
Test solution and Standard solution— Proceed as directed for Identification test A.
Developing solvent system— Prepare a mixture of solvent hexane and ethyl acetate (8:2). [note—Saturate the chromatographic chamber with the Developing solvent system vapors prior to the development of the chromatogram.]
Spray reagent— Prepare a solution containing 0.38 g of ceric ammonium sulfate and 3.8 g of ammonium molybdate in 100-mL of 2 N sulfuric acid.
Procedure— Develop the chromatogram until the solvent front has moved not less than 18 cm, and dry the plate with the aid of a current of air. Spray the plate with Spray reagent, heat the plate at 140 for 15 minutes, and examine under UV light: the blue zone due to hyperforin at an RF value of about 0.54 in the chromatogram of the Test solution corresponds in color and RF value to that in the chromatogram of the Standard solution.
Water, Method I 921: not more than 5.0%.
Total ash 561: not more than 7.0%.
Microbial enumeration 2021— It meets the requirements of the tests for absence of Salmonella species and Escherichia coli. The total bacterial count does not exceed 104 cfu per g, and the total combined molds and yeasts does not exceed 1000 cfu per g.
Pesticide residues 561— Proceed as directed for Test for Pesticides under Articles of Botanical Origin 561: meets the requirements.
Content of hypericin and pseudohypericin—
Solution A, Solution B, Solution C, Mobile phase, Standard solution 1, Standard solution 2, and Chromatographic system— Proceed as directed for the Content of hypericin and pseudohypericin test under St. John's Wort.
Test solution— Transfer about 25 mg of Powdered Extract, accurately weighed, to a 25-mL volumetric flask, add about 10 mL of a mixture of methanol and water (9:1), and sonicate. Dilute with a mixture of methanol and water (9:1) to volume, and mix. Pass through a polytef membrane filter having a 0.45-µm or finer porosity, and use the filtrate.
Procedure— Proceed as directed for the Content of hypericin and pseudohypericin test under St. John's Wort. Calculate the percentages of hypericin (C30H16O8) and pseudohypericin (C30H16O9) in the portion of Powdered Extract taken by the formula:
2500(C/FW)(rU / rS)
in which W is the weight, in mg, of Powdered Extract taken to prepare the Test solution; and the other terms are as defined therein. Add the percentages obtained for hypericin and pseudohypericin.
Content of hyperforin— Using the chromatograms obtained in the test for Content of hypericin and pseudohypericin, calculate the percentage of hyperforin (C35H52O4) in the portion of Powdered Extract taken by the formula:
2500(C/W 0.46)(rU / rS)
in which 0.46 is the response factor of hyperforin, relative to that of oxybenzone; rU is the response of the hyperforin peak in the chromatogram of the Test solution; and the other terms are as defined therein.
Other requirements— It meets the requirements for Residue on Evaporation and Residual Solvents under Botanical Extracts 565.
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Maged H. Sharaf, Ph.D.
Senior Scientist
1-301-816-8318		 (DSB05) Dietary Supplements - Botanicals
Reference Standards Lili Wang, Technical Services Scientist
1-301-816-8129
RSTech@usp.org
2021 Radhakrishna S Tirumalai, Ph.D.
Senior Scientist
1-301-816-8339		 (MSA05) Microbiology and Sterility Assurance
USP32–NF27 Page 1068
Pharmacopeial Forum: Volume No. 30(2) Page 584
Chromatographic Column—
Chromatographic columns text is not derived from, and not part of, USP 32 or NF 27.