Lagerstroemia speciosa Leaf Dry Extract

Lagerstroemia speciosa Leaf Dry Extract

Final Authorized Version 1.0

Lagerstroemia speciosa Leaf Dry Extract


 

DEFINITION

The extract is prepared from the dried leaves of Lagerstroemia speciosa (L.) Pers. (Family Lythraceae) by extraction with hydroalcoholic mixtures. It contains NLT 90.0% and NMT 110.0% of the labeled amount of corosolic acid, on the dried basis.

 

POTENTIAL CONFOUNDING MATERIALS

Terminalia cuneata Roth

 

CONSTITUENTS OF INTEREST

Pentacyclic triterpene acids: Corosolic acid, virgatic acid, ursolic acid, and oleanolic acid

 

IDENTIFICATION

• A. Thin-Layer Chromatography

Standard solution A: 0.2 mg/mL of USP Corosolic Acid RS in methanol

Standard solution B: 10 mg/mL of USP Lagerstroemia speciosa Leaf Dry Extract RS in methanol. Sonicate for 10 min, centrifuge, and use the supernatant.

Sample solution: Lagerstroemia speciosa Leaf Dry Extract in methanol at a concentration equivalent to 0.2 mg/mL of corosolic acid according to the label claim. Sonicate if necessary.

Chromatographic system

(See Chromatography <621>, Thin-Layer Chromatography.)

Adsorbent: Chromatographic silica gel mixture with an average particle size of 5 µm (HPTLC plates)

Application volume: 6 µL, as 8-mm bands

Relative humidity: Condition the plate to a relative humidity of about 33% using a suitable device.

Temperature: 25°

Developing solvent system: Toluene, ethyl acetate, and glacial acetic acid (55: 45: 0.5)

Developing distance: 6 cm

Derivatization reagent: Anisaldehyde reagent—85 mL of ice-cooled methanol mixed with 10 mL of glacial acetic acid, 5 mL of sulfuric acid, and 0.5 mL of p-anisaldehyde

Analysis

Samples: Standard solution A, Standard solution B, and Sample solution

Apply the Samples as bands to a suitable HPTLC plate and dry in air. Develop the chromatograms in an un-saturated chamber, remove the plate from the chamber, and dry. Treat with Derivatization reagent, and heat for 3 min at 100°. Examine under visible light.

System suitability: Under visible light, the chromatogram of Standard solution B exhibits the most intense band, a violet or blue band, with similar RF and color as the corosolic acid band in the chromatogram of Standard solution A; a blue band close to the start (about RF 0.1), consistent with asiatic acid; two minor blue bands in between corosolic and asiatic; above the band due to corosolic acid a minor blue band due to virgatic acid; and just below the latter, a minor brown band. Standard solution B also exhibits at about three-fourths of the chromatogram two minor violet bands, separated, the band with the lower RF corresponds to oleanolic acid.

Acceptance criteria: Under visible light, the chromatogram of the Sample solution exhibits the most intense band as a violet band corresponding in color and RF to the band due to corosolic acid in the chromatogram of Standard Solution A, and the following bands corresponding to similar bands in Standard solution B: a blue band close to the start (about RF 0.1); two minor purple bands below the corosolic acid; two minor blue bands above the corsolic acid; and two minor violet bands, that are separated, at about three-fourths of the chromatogram.

• B. HPLC

Analysis: Proceed as directed in the test for Content of Corosolic Acid.

Acceptance criteria: The chromatogram of the Sample solution exhibits a group of three peaks, the one in the center is the most intense of the group and occurs at a retention time corresponding to that of corosolic acid in the chromatogram of Standard solution A, the peak that elutes before corosolic acid has about one-half to one-third of the intensity of that of corosolic acid, and the peak eluting after corosolic acid has the lesser intensity of the three and is consistent with virgatic acid. A minor peak due to oleanolic acid elutes later in the chromatogram.

 

ASSAY

• Content of Corosolic Acid

Solution A: 0.1% Phosphoric acid in water

Solution B: Acetonitrile

Mobile phase: A mixture of Solution A and Solution B (4:6)

Standard solution A: 0.1 mg/mL of USP Corosolic Acid RS in methanol

Standard solution B: 5.0 mg/mL of USP Lagerstroemia speciosa Leaf Dry Extract RS in methanol; sonicate if necessary. Before injection, pass through a membrane filter of 0.45-µm or finer pore size. Discard the first few mL of the filtrate.

Sample solution: Lagerstroemia speciosa Leaf Dry Extract in methanol at a concentration equivalent to 0.1 mg/mL of corosolic acid according to the label claim, sonicate if necessary. Before injection, pass through a membrane filter of 0.45-µm or finer pore size. Discard the first few mL of the filtrate.

Chromatographic system

(See Chromatography <621>, System Suitability.)

Detector: UV 205 nm

Column: 4.6-mm × 25-cm; 5-µm packing L1 (similar to Hibar® 250-4,6; Lichrospher® 100, RP-18e; or Luna C18 100A)

Flow rate: 1.6 mL/min

Injection volume: 20 µL

System suitability

Samples: Standard solution A and Standard solution B

Suitability requirements

Chromatogram similarity: The chromatogram from Standard solution B is similar to the reference chromatogram provided with the lot of USP Lagerstroemia speciosa Leaf Dry Extract RS being used.

Resolution: NLT 1.5 between the corosolic acid peak and the peak before, Standard solution B

Tailing factor: NMT 2.0 for the corosolic acid peak, Standard solution A

Relative standard deviation: NMT 2.0%, determined from the corosolic acid peak in repeated injections, Standard solution A

Analysis

Samples: Standard solution A, Standard solution B, and Sample solution

Using the chromatograms of Standard solution A, Standard solution B, and the reference chromatogram provided with the lot of USP Lagerstroemia speciosa Leaf Dry Extract RS being used, identify the retention time of the peak corresponding to corosolic acid, virgatic acid, and oleanolic acid in the Sample solution chromatogram. The approximate relative retention times of the different peaks for corosolic acid, virgatic acid, and oleanolic acid are 1.0, 1.1, and 3.2, respectively.

Calculate the percentage of corosolic acid in the portion of Lagerstroemia speciosa Leaf Dry Extract taken:

 

Result = (rU/rS) × (CS/Cu) × 100

 

rU   = peak area of corosolic acid from the Sample solution

rS   = peak area of corosolic acid from Standard solution A

CS  = concentration of corosolic acid in Standard solution A (mg/mL)

CU  = concentration of Lagerstroemia speciosa Leaf Dry Extract in the Sample solution (mg/mL)

 

Calculate the percentage of the labeled amount of corosolic acid in the Extract: 

 

Result = (P/L) x 100

 

P = content of corosolic acid as determined above (%)

L = labeled amount of corosolic acid (%)

Acceptance criteria: 90.0%–110.0% of the labeled amount of corosolic acid, on the dried basis

 

CONTAMINANTS

Elemental Impurities—Procedures <233>

Acceptance criteria

Arsenic: NMT 2.0 µg/g

Cadmium: NMT 0.5 µg/g

Lead: NMT 5.0 µg/g

Mercury: NMT 0.2 µg/g

Articles of Botanical Origin, General Method for Pesticide Residues Analysis <561>: Meets the requirements

Microbial Enumeration Tests <61>: The total aerobic bacterial count does not exceed 105 cfu/g, the total combined molds and yeasts count does not exceed 103 cfu/g, and the bile-tolerant Gram-negative bacteria does not exceed 103 cfu/g.

Tests for Specified Microorganisms <62>: Meets the requirements of the tests for the absence of Salmonella species and Escherichia coli

 

SPECIFIC TESTS

Loss on Drying <731>

Analysis: Dry 2.0 g of Lagerstroemia speciosa Leaf Dry Extract at 105° for 2 h.

Acceptance criteria: NMT 8.0%

 

ADDITIONAL REQUIREMENTS

• Packaging and Storage: Preserve in well-closed containers, protected from light and moisture, and store at controlled room temperature.

• Labeling: The label states the Latin binomial and, following the official name, the part of the plant from which the article was derived. It meets other labeling requirements under Botanical Extract <565>.

USP Reference Standards <11>

USP Corosolic Acid RS

USP Lagerstroemia speciosa Leaf Dry Extract RS

Other Versions

Proposed For Comment Version 0.2