Powdered Turmeric
Powdered Turmeric is Turmeric reduced to a fine or very fine powder.
•  A. Thin-Layer Chromatographic Identification Test
Standard solution:  0.2 mg/mL of USP Curcuminoids RS in acetone
Sample solution:  Transfer about 0.2 g of Powdered Turmeric to a test tube, add 3 mL of acetone, sonicate for 30 min, and centrifuge. Use the supernatant.
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 a 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 in daylight and 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)
[Note—Sonication may be necessary to dissolve the Reference Standard in each Standard solution; all solutions should be passed through a filter of 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 stock solution:  Transfer about 0.5 g of Powdered Turmeric, accurately weighed, to a 50-mL volumetric flask, add 30 mL of acetone, and sonicate for 30 min. Dilute with acetone to volume, mix, and centrifuge.
Sample solution:  Transfer 5 mL of the Sample stock solution to a 50 mL volumetric flask. Dilute with Mobile phase to volume, and mix.
Chromatographic system 
Mode:  LC
Detector:  UV-Vis 420 nm
Column:  4.6-mm × 20-cm; 5-µm packing L1
Flow rate:  1 mL/min
Injection size:  20 µL
System suitability 
Sample:  Standard solution A
[Note—The relative retention times for the curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin peaks are 1.0, 1.2, and 1.4, respectively. ]
Suitability requirements 
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 Powdered Turmeric taken:
Result = (rU/rS) × CS × (V/W) × D × 100
rU== peak response for curcumin, desmethoxycurcumin, or bisdesmethoxycurcumin from the Sample solution
rS== peak response for curcumin, desmethoxycurcumin, or bisdesmethoxycurcumin from the appropriate Standard solution
CS== concentration of the appropriate Standard solution (mg/mL)
V== volume of the Sample stock solution (mL)
W== weight of Powdered Turmeric used to prepare the Sample stock solution (mg)
D== dilution factor to prepare the Sample solution from the Sample stock solution
Acceptance criteria:  NLT 3% as the sum of curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin
•  Heavy Metals, Method III 231: NMT 20 ppm
•  Microbial Enumeration Tests 2021: 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.
•  Microbiological Procedures for Absence of Specified Microorganisms 2022: Meets the requirements of the tests for the absence of Salmonella species and Escherichia coli.
•  Botanic Characteristics: It is deep yellow in color, with a characteristic aromatic odor. Under a microscope, Powdered Turmeric reveals thin-walled parenchyma cells containing starch granules, 15–30 mm in size, flat or disk shaped, gelatinized or ungelatinized; oil cells full of oil and scattered particles of orange-yellow pigments; prisms of calcium oxalate, usually obscured due to the bright yellow color of the pigment content, detected as bright orange prisms under a polarizing microscope; fragments of spiral vessels and a few reticulate and annular vessels; fragments of epidermal and cork cells; starch granules; scattered unicellular nonglandular trichomes; and the absence of bast fibers.
•  Packaging and Storage: Preserve in well-closed containers. Protect from light and moisture, and store at room temperature.
•  Labeling: The label states the Latin binomial and, following the official name, the part of the plant contained in the article.
•  USP Reference Standards 11
USP Bisdesmethoxycurcumin RS
USP Curcumin RS
USP Curcuminoids RS
USP Desmethoxycurcumin RS
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(GCM2010) General Chapters - Microbiology
2022 Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison
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Reference Standards RS Technical Services
USP35–NF30 Page 1458
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