Boswellia serrata Extract
DEFINITION
Boswellia serrata Extract is prepared from pulverized Boswellia serrata, using suitable solvents such as isopropanol, alcohol, methanol, hexanes, or mixtures of these solvents. The ratio of starting plant material to Extract is approximately 6:1. It contains NLT 90.0% and NMT 110.0% of the labeled amount of Extract, calculated, on the dried basis, as the sum of 11-keto--boswellic acid and 3-acetyl-11-keto--boswellic acid; it may contain suitable added substances.
IDENTIFICATION
•  A. Thin-Layer Chromatographic Identification Test 201
Standard solution:  Treat a quantity of USP Boswellia serrata Extract RS with gentle heating in methanol to obtain a solution having a known concentration of 30 mg/mL, cool, centrifuge, and use the supernatant.
Sample solution:  Treat a quantity of Extract with gentle heating in methanol to obtain a solution having a known concentration of 30 mg/mL, cool, centrifuge, and use the supernatant.
Adsorbent:  0.25-mm layer of chromatographic silica gel
Developing solvent system:  A mixture of hexane and ethyl acetate (6:4)
Dipping reagent:  Prepare a solution of 10% sulfuric acid in methanol. [Note—Prepare fresh immediately before use. ]
Application volume:  10 µL
Analysis 
Samples:  Standard solution and Sample solution
Apply the Samples as bands to a suitable thin-layer chromatographic plate (see Chromatography 621). Use a saturated chamber. Develop until the solvent front has moved up about 90% of the plate. Remove, dry, and examine under UV light at 254 nm. Dip in the Dipping reagent, heat for 5–10 min at 100, and examine under visible light.
Acceptance criteria:  Under UV light at 254 nm, the Sample solution exhibits two main zones due to 11-keto--boswellic acid and 3-acetyl-11-keto--boswellic acid at RF values of about 0.30 and 0.36, respectively, corresponding to zones from the Standard solution. Under visible light, the Sample solution exhibits two additional zones due to -boswellic acid and 3-acetyl--boswellic acid at RF values of about 0.49 and 0.58, respectively, corresponding to zones from the Standard solution. Other, less intense zones are observed for the Sample solution and the Standard solution.
•  B. The 210-nm chromatogram of the Sample solution, in the test for Content of Keto-Derivatives of -Boswellic Acids, exhibits peaks for 11-keto--boswellic acid, 3-acetyl-11-keto--boswellic acid, -boswellic acid, and 3-acetyl--boswellic acid at retention times that correspond to those in the 210-nm chromatogram of Standard solution B and the 210-nm Reference Chromatogram provided with the USP Boswellia serrata Extract RS.
COMPOSITION
•  Content of Keto-Derivatives of -Boswellic Acids
Standard solution A:  Dissolve a quantity of USP 3-Acetyl-11-keto--Boswellic Acid RS in methanol to obtain a solution having a known concentration of 0.1 mg/mL.
Standard solution B:  Treat a quantity of USP Boswellia serrata Extract RS with gentle heating in methanol to obtain a solution having a known concentration of 10 mg/mL. Before injection, pass through a filter of 0.45-µm pore size.
Sample solution:  Treat a quantity of Extract with gentle heating in methanol to obtain a solution having a known concentration of 10 mg/mL. Before injection, pass through a filter of 0.45-µm pore size, and discard the first few mL of the filtrate.
Mobile phase:  Prepare a filtered and degassed mixture of acetonitrile, water, and glacial acetic acid (900:100:0.1). Make adjustments if necessary.
Chromatographic system 
Mode:  LC
Detector:  UV 254 nm
Column:  4.6-mm × 25-cm; packing L1
Flow rate:  See the gradient table below.
Time
(min)
Flow Rate
(mL/min)
0 1
5 1.5
10 2
30 2
32 1
45 1
Injection size:  20 µL
System suitability 
Samples:  Standard solution A and Standard solution B
[Note—The relative retention times for 11-keto--boswellic acid and 3-acetyl-11-keto--boswellic acid are about 1.0 and 1.4, respectively. ]
Suitability requirements:  The chromatogram of Standard solution B is similar to the 254-nm Reference Chromatogram provided with the USP Boswellia serrata Extract RS.
Tailing factor:  NMT 1.5, 11-keto--boswellic acid peak, Standard solution A
Relative standard deviation:  NMT 2.0% of the 3-acetyl-11-keto--boswellic acid peak response for replicate injections, Standard solution A
Analysis 
Samples:  Standard solution A, Standard solution B, and Sample solution
Using the chromatogram of Standard solution B and the 254-nm Reference Chromatogram provided with the lot of USP Boswellia serrata Extract RS, identify the retention times of the peaks of 11-keto--boswellic acid and 3-acetyl-11-keto--boswellic acid in the Sample solution chromatogram.
Separately calculate the percentages of 11-keto--boswellic acid and 3-acetyl-11-keto--boswellic acid in the portion of Extract taken:
Result = (rU/rS) × (CSV/W) × 100F
rU== peak area of each analyte from the Sample solution
rS== peak area of 3-acetyl-11-keto--boswellic acid from Standard solution A
CS== concentration of USP 3-Acetyl-11-keto--Boswellic Acid RS in Standard solution A (mg/mL)
V== final volume of the Sample solution (mL)
W== weight of Extract taken to prepare the Sample solution (mg)
F== conversion factor for each analyte (0.93 for 11-keto--boswellic acid and 1.0 for 3-acetyl-11-keto--boswellic acid)
Acceptance criteria:  Add the percentages of the two analytes. It contains NLT 90.0% and NMT 110.0% of the labeled amount of Extract, calculated on the dried basis, as the sum of 11-keto--boswellic acid and 3-acetyl-11-keto--boswellic acid.
IMPURITIES
Inorganic Impurities 
•  Heavy Metals, Method II 231: NMT 20 ppm
SPECIFIC TESTS
•  Loss on Drying 731: Dry 1.0 g of Extract at 105 for 2 h: it loses NMT 5.0% of its weight.
•  Microbial Enumeration Tests 2021: The total aerobic bacterial count does not exceed 104 cfu/g, and the total combined molds and yeasts count does not exceed 103 cfu/g.
•  Microbiological Procedures for Absence of Specified Microorganisms 2022: Meets the requirements of the tests for absence of Salmonella species and Escherichia coli.
ADDITIONAL REQUIREMENTS
•  Packaging and Storage: Preserve in well-closed containers, protected from light and moisture, and store in a cool place.
•  Labeling: The label states the Latin binomial and, following the official name, the part of the plant from which the article was prepared. It meets other labeling requirements under Botanical Extracts 565.
•  USP Reference Standards 11
USP 3-Acetyl-11-keto--Boswellic Acid RS Click to View Structure
USP Boswellia serrata Extract RS
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Topic/Question Contact Expert Committee
Monograph Maged H. Sharaf, Ph.D.
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2021 Radhakrishna S Tirumalai, Ph.D.
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2022 Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison
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USP35–NF30 Page 1215
Pharmacopeial Forum: Volume No. 35(4) Page 891