Garcinia indica
DEFINITION
Garcinia indica consists of the dried pericarp of the fruits of Garcinia indica (Thouars) Choisy (Fam. Clusiaceae). It contains NLT 12% of the sum of (–)-hydroxycitric acid and (–)-hydroxycitric acid lactone, on the dried basis.
IDENTIFICATION
•  A. Garcinia indica meets the requirements under Specific Tests, Botanic Characteristics.
•  B. Thin-Layer Chromatographic Identification Test
Standard solution:  0.5 mg/mL of garcinol in alcohol
Sample solution:  Transfer about 2.0 g of Garcinia indica, finely powdered, to a Soxhlet apparatus, add 100 mL of alcohol, and extract for 6 h. Filter and concentrate under vacuum to about 10 mL. [Note—Use a thimble of suitable size such that the volume of alcohol used in the Soxhlet extraction is at least twice the volume of the thimble. ]
Adsorbent:  Chromatographic silica gel mixture with an average particle size of 5 µm (HPTLC plates)
Application volume:  5 µL, as 8-mm bands
Developing solvent system:  Toluene, ethyl acetate, and formic acid (4:1:0.5)
Spray reagent:  A mixture of 1% vanillin in alcohol and 10% sulfuric acid in alcohol (1:1)
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 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, spray with Spray reagent, heat for 5–10 min at about 105, and examine under visible light.
Acceptance criteria:  The Sample solution chromatogram exhibits a main greenish-grey band due to garcinol at an RF value of approximately 0.6, which corresponds in position and color to the main band in the chromatogram of the Standard solution. The Sample solution exhibits the following additional bands: two purple bands, two greenish-grey bands, two blue bands and a purple band at RF values of approximately 0.31, 0.34, 0.37, 0.47, 0.54, 0.83, and 0.93, respectively. Other bands may be observed for the Sample solution.
•  C. HPLC Identification Test: The Sample solution chromatogram exhibits a peak for hydroxycitric acid at a retention time corresponding to that of Standard solution A, as obtained in the test for Content of (–)-Hydroxycitric Acid and (–)-Hydroxycitric Acid Lactone. The Sample solution also exhibits a peak for hydroxycitric acid lactone. The hydroxycitric acid and the hydroxycitric acid lactone peaks are the main peaks in the Sample solution chromatogram.
COMPOSITION
•  Content of (–)-Hydroxycitric Acid and (–)-Hydroxycitric Acid Lactone
Solution A:  30% phosphoric acid in water
Mobile phase:  Dissolve 1.36 g of anhydrous potassium dihydrogen phosphate in 900 mL of water, adjust with Solution A to a pH of 2.5, complete with water to 1000 mL, mix, filter, and degas.
Solvent:  A mixture of Solution A and water (1:9)
Standard solution A:  A solution of USP Calcium (–)-Hydroxycitrate RS equivalent to about 4 mg/mL of (–)-hydroxycitric acid in Solvent. Before injection, pass through a membrane filter of 0.45-µm or finer pore size, discarding the first few mL of the filtrate.
Standard solution B:  8 mg/mL of USP Powdered Garcinia Hydroxycitrate Extract RS in Solvent. Before injection, pass through a membrane filter of 0.45-µm or finer pore size.
Sample solution:  Transfer about 5 g of Garcinia indica, finely powdered and accurately weighed, to a 250-mL round-bottom flask fitted with a reflux condenser. Add 50 mL of Solvent, reflux while stirring on a water bath for 30 min, set aside to settle, and decant the supernatant. Repeat the extraction using four 50-mL portions of water, combine all extracts, cool, filter into a 250-mL volumetric flask, and complete with water to volume. Before injection, pass through a membrane filter of 0.45-µm or finer pore size, discarding the first few mL of the filtrate.
Chromatographic system 
Mode:  LC
Detector:  UV 215 nm
Column:  4.6-mm × 25-cm; packing L1
Column temperature:  25 ± 1
Flow rate:  1.0 mL/min
Injection size:  20 µL
System suitability 
Samples:  Standard solution A, Standard solution B, and Sample solution
[Note—The relative retention times for the hydroxycitric acid lactone and hydroxycitric acid peaks are about 0.9 and 1.0, respectively. ]
Suitability requirements 
Chromatogram similarity:  The chromatogram from Standard solution B is similar to the reference chromatogram provided with the lot of USP Powdered Garcinia Hydroxycitrate Extract RS being used.
Resolution:  NLT 1.0 between the hydroxycitric acid lactone and hydroxycitric acid peaks, Sample solution
Tailing factor:  NMT 2.0 for the hydroxycitric acid peak, Standard solution A
Relative standard deviation:  NMT 2.0%, determined from the hydroxycitric acid peak for replicate injections, Standard solution A
Analysis 
Samples:  Standard solution A, Standard solution B, and Sample solution. [Note—Standard solution A, Standard solution B, and the Sample solution are stable for 6 h. ]
Calculate the percentages of (–)-hydroxycitric acid and (–)-hydroxycitric acid lactone in the portion of Garcinia indica taken:
Result = (rU/rS) × CS × (V/W) × F × 100
rU== peak area of the relevant analyte from the Sample solution
rS== peak area of hydroxycitric acid from Standard solution A
CS== concentration of (–)-hydroxycitric acid in Standard solution A (mg/mL)
V== final volume of the Sample solution (mL)
W== weight of Garcinia indica used to prepare the Sample solution (mg)
F== conversion factor for each analyte: 2.17 for (–)-hydroxycitric acid lactone, and 1.00 for (–)-hydroxycitric acid
Acceptance criteria:  Add the percentages of (–)-hydroxycitric acid and (–)-hydroxycitric acid lactone: NLT 12% is found on the dried basis.
IMPURITIES
Inorganic Impurities 
•  Heavy Metals, Method III 231: NMT 20 ppm
Organic Impurities 
SPECIFIC TESTS
•  Botanic Characteristics
Macroscopic:  Fresh fruits are globular in shape, 3–4 cm in diameter, purplish to pinkish orange when ripe, with persistant calyx lobes at the base and flattened radiating sessile stigma at the apex; containing 5–8 seeds surrounded by a succulant aril. Compendial article consists of dried pieces of pericarp, bluish black, of various size and shapes, flattened, flexible; remains of pedicels, calyx, and stigma may be present; odor characteristic; taste sour.
Histology 
Transverse section of the pericarp:  A layer of epicarp, composed of isodiametric cells, with thin cuticle and stomata; hypodermis consisting of several rows of compactly arranged, tangentially elongated, thick-wall cells, containing dark brown contents, showing narrow irregular elongated cavities; outer mesocarp consisting of loosely arranged, tangentially elongated, parenchyma cells, few are full of starch grains, traversed by narrow bands of collapsed cells and oleoresin ducts; inner mesocarp consisting of collapsed and compactly arranged cells, showing rows of fibrovascular bundles; endocarp is not distinct, consisting of thin-wall collapsed cells, with dark brown content.
•  Limit of Citric Acid
Solvent and Chromatographic system:  Prepare as directed in the test for Content of (–)-Hydroxycitric Acid and (–)-Hydroxycitric Acid Lactone.
Standard solution:  0.5 mg/mL of USP Citric Acid RS in Solvent. Before injection, pass through a membrane filter of 0.45-µm or finer pore size, discarding the first few mL of the filtrate.
Analysis 
Sample:  Standard solution
Calculate the percentage of citric acid in the portion of Garcinia indica taken:
Result = (rU/rS) × CS × (V/W) × 100
rU== peak area of citric acid from the Sample solution in the test for Content of (–)-Hydroxycitric Acid and (–)-Hydroxycitric Acid Lactone
rS== peak area of citric acid from the Standard solution
CS== concentration of USP Citric Acid RS in the Standard solution (mg/mL)
V== final volume of the Sample solution (mL)
W== weight of Garcinia indica used to prepare the Sample solution in the test for Content of (–)-Hydroxycitric Acid and Limit of (–)-Hydroxycitric Acid Lactone (mg)
Acceptance criteria:  NMT 2% of citric acid on the dried basis
•  Loss on Drying 731: Dry 2.0 g of finely powdered Garcinia indica at 105 for 3 h: it loses NMT 12.0% of its weight.
•  Articles of Botanical Origin, Total Ash 561: Determined on 1.0 g of finely powdered Garcinia indica: NMT 3.0%; and NMT 8.0% if sodium chloride was added as a preservative during collection of the fruits.
•  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 do 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 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 Calcium (–)-Hydroxycitrate RS
USP Citric Acid RS Click to View Structure
USP Powdered Garcinia Hydroxycitrate Extract RS
Auxiliary Information— Please check for your question in the FAQs before contacting USP.
Topic/Question Contact Expert Committee
Monograph Maged H. Sharaf, Ph.D.
Principal Scientific Liaison
1-301-816-8318
(DS2010) Monographs - Dietary Supplements
2021 Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison
1-301-816-8339
(GCM2010) General Chapters - Microbiology
2022 Radhakrishna S Tirumalai, Ph.D.
Principal Scientific Liaison
1-301-816-8339
(GCM2010) General Chapters - Microbiology
Reference Standards RS Technical Services
1-301-816-8129
rstech@usp.org
USP35–NF30 Page 1306
Pharmacopeial Forum: Volume No. 36(3) Page 703