A: Thin Layer Chromatographic Identification Test 201—

B: The chromatogram of the Test solution exhibits peaks for speciophylline, uncarine F, mitraphylline, isomitraphylline, pteropodine, and isopteropodine at retention times that correspond to those in the chromatogram of Standard solution 1, 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.

Solution A, Solution B, Solution C, Mobile phase, Standard solution 1, Standard solution 2, and Chromatographic system— Proceed as directed in the test for Content of pentacyclic oxindole alkaloids and limit of tetracyclic oxindoles under Cat's Claw.

Test 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 minutes. Centrifuge, and transfer the supernatant to a 10-mL volumetric flask. Repeat the above 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 minute. Pass through a nylon filter having a 0.45-µm or finer porosity, discarding the first part of the filtrate.

Procedure— Proceed as directed in the test for Content of pentacyclic oxindole alkaloids and limit of tetracyclic oxindole alkaloids under Cat's Claw. Separately calculate the percentage of each relevant alkaloid in the portion of Powdered Extract taken by the formula: in which W is the weight, in g, of Powdered Extract taken to prepare the Test solution; and the other terms are as defined therein. Calculate the percentage of pentacyclic oxindole alkaloids in the Powdered Extract taken by adding the individual percentages of speciophylline, uncarine F, mitraphylline, isomitraphylline, pteropodine, and isopteropodine. Calculate the percentage of tetracyclic oxindole alkaloids in the Powdered Extract taken by adding the individual percentages of rhynchophylline and isorhynchophylline: not more than 25% of the labeled amount of pentacyclic oxindole alkaloids is found.