Curcuminoids is a partially purified natural complex of diaryl heptanoid derivatives isolated from Turmeric, Curcuma longa L. It contains NLT 95.0% of curcuminoids, calculated on the dried basis, as the sum of curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin. It contains NLT 70.0% and NMT 80.0% of curcumin, NLT 15.0% and NMT 25.0% of desmethoxycurcumin, and NLT 2.5% and NMT 6.5% of bisdesmethoxycurcumin.
• A. Thin-Layer Chromatographic Identification Test
Standard solution: 0.2 mg/mL of USP Curcuminoids RS in acetone
Sample solution: 2 mg/mL of Curcuminoids in acetone
Adsorbent: 0.25-mm layer of chromatographic silica gel mixture, typically 20 cm long (TLC plates)
Application volume: 10 µL, as bands
Developing solvent system: Chloroform, methanol, and formic acid (96:4:1)
Samples: Standard solution and Sample solution
Apply the samples as bands to a suitable thin-layer chromatographic plate (see Chromatography 621, Thin-Layer Chromatography). Use saturated chamber. Develop the chromatograms until the solvent front has moved up about three-fourths of the length of the plate. Remove the plate from the chamber, dry, and examine under UV light at 365 nm.
Acceptance criteria: The Sample solution chromatogram shows yellowish-brown bands due to bisdesmethoxycurcumin, desmethoxycurcumin, and curcumin at RF values of about 0.4, 0.6, and 0.7, respectively, corresponding in position and color to those obtained from the Standard solution.
• B. The retention times of the peaks for curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin of the Sample solution chromatogram correspond to those of the Standard solution for the appropriate USP Reference Standard, as obtained in the test for Content of Curcuminoids.
• Content of Curcuminoids
Mobile phase: Tetrahydrofuran and 1 mg/mL of citric acid in water (4:6)
[NoteSonication may be necessary to dissolve the RS in each Standard solution; all solutions should be passed through a filter with 0.45-µm pore size before injection. USP Curcumin RS, USP Desmethoxycurcumin, and USP Bisdesmethoxycurcumin RS can also be prepared in one standard solution containing the final concentration specified below for each. ]
Standard solution A: 40 µg/mL of USP Curcuminoids RS in Mobile phase
Standard solution B: 40 µg/mL of USP Curcumin RS in Mobile phase
Standard solution C: 10 µg/mL of USP Desmethoxycurcumin RS in Mobile phase
Standard solution D: 2 µg/mL of USP Bisdesmethoxycurcumin RS in Mobile phase
Sample solution: Transfer about 20 mg of Curcuminoids to a 50-mL volumetric flask, add about 30 mL of acetone, and sonicate for 30 min. Dilute with acetone to volume and centrifuge. Transfer 5 mL to a 50-mL volumetric flask, dilute with Mobile phase to volume, and mix.
Detector: UV 420 nm
Column: 4.6-mm × 20-cm; 5-µm packing L1
Flow rate: 1 mL/min
Injection size: 20 µL
Sample: Standard solution A
[NoteThe relative retention times for the curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin peaks are 1.0, 1.2, and 1.4, respectively. ]
Chromatogram similarity: The chromatogram of Standard solution A is similar to the Reference Chromatogram provided with USP Curcuminoids RS.
Resolution: NLT 2.0, between curcumin and desmethoxycurcumin peaks and the desmethoxycurcumin and bisdesmethoxycurcumin peaks
Tailing factor: NMT 1.5 for bisdesmethoxycurcumin, desmethoxycurcumin, and curcumin peaks
Relative standard deviation: NMT 2.0% for desmethoxycurcumin peak, in repeated injections
Samples: Standard solution A, Standard solution B, Standard solution C, Standard solution D, and Sample solution
Calculate the percentage of curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin in the portion of Curcuminoids taken:
Result = (rU/rS) × (CS/CU) × 100
Acceptance criteria: Curcuminoids contains NLT 95.0% of curcuminoids, calculated on the dried basis, as the sum of curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin. It contains NLT 70.0% and NMT 80.0% of curcumin, NLT 15.0% and NMT 25.0% of desmethoxycurcumin, and NLT 2.5% and NMT 6.5% of bisdesmethoxycurcumin.
• Heavy Metals, Method III 231: NMT 20 ppm
• Articles of Botanical Origin, Pesticide Residues 561: Meets the requirements
• Articles of Botanical Origin, Test for Aflatoxins 561: Meets the requirements
• 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 Procedure for Absence of Specified Microorganisms 2022: Meets the requirements of the tests for the absence of Salmonella species and Escherichia coli
• Melting Range or Temperature, Class I 741: 172178
• Loss on Drying 731: Dry 1.0 g at 105 for 2 h: it loses NMT 2.0% of its weight.
• Articles of Botanical Origin, Total Ash 561: NMT 1.0%
• Packaging and Storage: Preserve in well-closed containers; protect from light and moisture, and store at room temperature.
• Labeling: The label states the content of curcuminoids and the content of the individual curcuminoids, on the dried basis; and the Latin binomial and the part of the plant used to prepare the article.
• USP Reference Standards 11
USP Bisdesmethoxycurcumin RS
USP Curcumin RS
USP Curcuminoids RS
USP Desmethoxycurcumin RS
Auxiliary Information Please check for your question in the FAQs before contacting USP.
USP35NF30 Page 1260Pharmacopeial Forum: Volume No. 33(6) Page 1215