Powdered Cat's Claw Extract
Powdered Cat's Claw Extract is prepared from Cat's Claw by extraction with hydroalcoholic mixtures or other suitable solvents. The ratio of plant material to extract is between 4:1 to 6:1. It contains NLT 90.0% and NMT 110.0% of the labeled amount of pentacyclic oxindole alkaloids as isopteropodine, calculated on the dried basis, as the sum of speciophylline, uncarine F, mitraphylline, isomitraphylline, pteropodine, and isopteropodine. It may contain suitable added substances.
• A. Thin-Layer Chromatographic Identification Test
Standard solution: 100 mg of USP Powdered Cat's Claw Extract RS in 2 mL of methanol. Sonicate for 5 min, shaking occasionally, heat in a water bath at 60 for 15 min, cool, and centrifuge.
Sample solution: Shake a quantity of Powdered Extract, equivalent to about 25 mg of the labeled amount of pentacyclic oxindole alkaloids, in 20 mL of methanol. Allow to stand for 15 min before use.
Adsorbent: Chromatographic silica gel mixture with an average particle size of 1015 µm (TLC plates)
Application volume: 20 µL, as bands that are 1 cm in length
Developing solvent system: Ethyl acetate and hexane (95:5)
Spray reagent A: Dissolve 0.85 g of basic bismuth nitrate in 10 mL of glacial acetic acid and 40 mL of water by heating. Filter if necessary (Solution A). Dissolve 8 g of potassium iodide in 30 mL of water (Solution B). Mix Solution A and Solution B (1:1) to obtain a stock solution. Dilute 1 mL of the stock solution with 2 mL of glacial acetic acid and 10 mL of water. [NoteUse freshly mixed Solution A and Solution B. ]
Spray reagent B: Use a 10% solution of sodium nitrite in water.
Samples: Standard solution and Sample solution
Develop the chromatogram to a length of NLT 12 cm, and dry the plate in a current of air.
Acceptance criteria: Examine the plate under short UV light. The Sample solution chromatogram shows multiple zones that correspond in RF values to those observed from the Standard solution chromatogram. Other zones of varying intensities may be observed in the Sample solution. Spray the plate with Spray reagent A followed by Spray reagent B, and examine the plate under daylight. The Sample solution chromatogram shows multiple orange-brown zones that correspond in color and RF values to those observed in the Standard solution chromatogram. Other colored zones of varying intensities may be observed in the Sample solution.
• B. The chromatogram of the Sample solution exhibits peaks for speciophylline, uncarine F, mitraphylline, isomitraphylline, pteropodine, and isopteropodine at retention times that correspond to those of Standard solution A, as obtained in the test for Content of Pentacyclic Oxindole Alkaloids and Limit of Tetracyclic Oxindole Alkaloids. The sum of the peak areas for the tetracyclic oxindole alkaloids rhynchophylline and isorhynchophylline is less than 25% of the total peak areas detected for pentacyclic oxindole alkaloids.
• Content of Pentacyclic Oxindole Alkaloids and Limit of Tetracyclic Oxindoles
Standard solution A: Dissolve an accurately weighed quantity of USP Powdered Cat's Claw Extract RS in methanol, shaking for 1 min. Dilute with methanol to obtain a solution having a known concentration of about 0.5 mg of the labeled amount of total oxindole alkaloids per mL. Pass through a filter of 0.45-µm or finer pore size.
Standard solution B: 0.1 mg/mL of USP Isopteropodine RS in methanol. Pass through a nylon filter of 0.45-µm or finer pore size.
Sample solution: Transfer an accurately weighed quantity of Powdered Extract, equivalent to about 5 mg of the labeled content of pentacyclic oxindole alkaloids, to a 10-mL centrifuge tube. Add 2.5 mL of methanol, and sonicate for 10 min. Centrifuge, and transfer the supernatant to a 10-mL volumetric flask. Repeat the extraction three additional times combining the extracts in the 10-mL volumetric flask, and dilute with methanol to volume. Transfer about 3 mL of the solution to a test tube containing 300 mg of polyamide powder, and shake for 1 min. Pass through a nylon filter of 0.45-µm or finer pore size, discarding the first part of the filtrate.
Solution A: Prepare a filtered and degassed 10 mM pH 7.0 phosphate buffer by mixing 6 mL of 1 N sodium hydroxide, 10 mL of 1 M monobasic potassium phosphate, and sufficient water to make 1000 mL. Adjust to a pH of 7.0 ± 0.1 by adding more of either solution.
Solution B: Acetonitrile
Solution C: Methanol and glacial acetic acid (99:1)
Mobile phase: See Table 1.
Detector: UV 245 nm
Column: 4.6-mm × 10-cm; end-capped 3-µm packing L1
Flow rate: 0.75 mL/min
Injection size: 10 µL
Samples: Standard solution A and Standard solution B
Chromatogram similarity: The chromatogram obtained using Standard solution A is similar to the Reference Chromatogram provided with the USP Powdered Cat's Claw Extract RS being used.
Tailing factor: NMT 2.0 for the isopteropodine peak, Standard solution B
Relative standard deviation: NMT 2.0% for the isopteropodine peak in repeated injections, Standard solution B
Samples: Standard solution A, Standard solution B, and Sample solution
Measure the areas of the analyte peaks. Identify the retention times of the peaks corresponding to speciophylline, uncarine F, mitraphylline, isomitraphylline, rhynchophylline, isorhynchophylline, pteropodine, and isopteropodine by comparison of the chromatogram of Standard solution A with the Reference Chromatogram provided with the lot of the USP Powdered Cat's Claw Extract RS used.
Separately calculate the percentages of speciophylline, uncarine F, mitraphylline, isomitraphylline, rhynchophylline, isorhynchophylline, pteropodine, and isopteropodine, as isopteropodine, in the portion of Powdered Extract taken:
Result = (rU/rS) × (CS/CU) × 100
Calculate the percentage of the labeled amount of pentacyclic oxindole alkaloids in the Powdered Extract:
Result = (SPA/L) × 100
Calculate the content of tetracyclic oxindole alkaloids by adding the individual percentages of rhynchophylline and isorhynchophylline.
Pentacyclic oxindole alkaloids: 90.0%110.0% of the labeled amount on the dried basis
Tetracyclic oxindole alkaloids: NMT 25% of the labeled amount of pentacyclic oxindole alkaloids on the dried basis
• Heavy Metals, Method II 231: NMT 10 ppm
• Microbial Enumeration Tests 2021: Meets the requirements of the tests for absence of Salmonella species and Escherichia coli. The total aerobic microbial count does not exceed 104/g, and the total combined molds and yeasts count does not exceed 103/g.
• Other Requirements: It meets the requirements for Botanical Extracts 565, Residual Solvents and Pesticide Residues.
• Loss on Drying 731: Dry 1 g at 105 for 2 h: it loses NMT 10.0% of its weight.
• Packaging and Storage: Preserve in tight, light-resistant containers, and store at room temperature.
• 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 pentacyclic oxindole alkaloids, the extracting solvent or solvent mixture used for preparation, and the ratio of the starting crude plant material to Powdered Extract. It meets the requirements for Botanical Extracts 565, Labeling.
• USP Reference Standards 11
USP Isopteropodine RS
USP Powdered Cat's Claw Extract RS
Auxiliary Information Please check for your question in the FAQs before contacting USP.
USP35NF30 Page 1228Pharmacopeial Forum: Volume No. 32(4) Page 1124