Turmeric is the dried rhizome of Curcuma longa L., also known as C. domestica Val., (Fam. Zingiberaceae). It is commonly known as Curcuma, Curcum, Haridra, and Indian Saffron. It contains NLT 3.0% of curcuminoids, calculated on the dried basis.
•  A. Thin-Layer Chromatographic Identification Test
Standard solution:  0.2 mg/mL of USP Curcuminoids RS in acetone
Sample solution:  Pulverize about 5 g of Turmeric. Transfer about 0.2 g of the pulverized sample 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:  Pulverize about 5.0 g of Turmeric. Transfer about 0.5 g of the pulverized sample 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 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 the 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 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 Turmeric used to prepare the Sample stock solution (mg)
D== dilution factor to obtain the Sample solution from the Sample stock solution
Acceptance criteria:  NLT 3% as the sum of curcumin, desmethoxycurcumin, and bisdesmethoxycurcumin on the dried basis
•  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
Macroscopic:  Turmeric occurs as ovate, oblong, or pear-shaped primary rhizomes, also known as bulb or round turmeric, about 3 cm in diameter and 4–5 cm long, and showing transverse annular leaf scars, and as cylindrical, sometimes short-branched secondary rhizomes, also known as finger or long turmeric, about 1 cm in diameter and 2–7 cm long, and showing scars of lateral branches. The cured and dried turmeric of commerce is bright yellow to dull yellow in appearance, with a rough or polished surface, and a characteristic aromatic odor. The texture is hard and uneasily broken, and the fracture is smooth and finely granular. Internally it is orange-yellow to orange, showing a cortex separated from a central cylinder by a distinct endodermis.
Transverse section of rhizome:  It shows a row of thin-walled, flattened epidermal cells; a few layers of thin-walled, brick-shaped parenchyma cells of the cork; a broad cortex consisting of multiple layers of thin-walled parenchyma cells showing scattered vascular bundles; a thin layer of oblong cells of the endodermis; pericycle consisting of one to two rows of parenchyma cells; and a pith consisting of parenchyma cells showing scattered vascular bundles, most of them forming discontinuous rings near the endodermis and fewer inward. The vascular bundles are of the collateral type; the vessels have mainly spiral thickening, and a few have reticulate and annular thickening. Scattered throughout the parenchyma of the pith and cortex are oleoresin cells containing oil and scattered particles of an orange-yellow pigment, and prisms of calcium oxalate, which are usually obscured due to the bright yellow color of the pigment content. The parenchyma cells are full of starch granules, 15–30 mm in size, and flat or disk shaped. Bast fibers are absent.
•  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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