- Description: Brownish- yellow powder.
- Solubility: Soluble in water.
- Identification:
- Thin-layer chromatographic
Test for flavonoids
Standard solution: A solution of 0.6 mg/mL of USP Rutin RS, 0.2 mg/mL of USP Chlorogenic Acid RS, and 0.2 mg/mL of USP Quercetin RS in methanol
Sample solution: Transfer 1.0 g of finely powdered Ginkgo to a 50-mL round-bottom flask fitted with a reflux condenser. Add 10 mL of methanol, reflux in a water bath for 10 min, allow to cool to room temperature, and filter. [NOTE—Reserve some of the Sample solution for use in the Test for terpene lactones.]
Adsorbent: Chromatographic silica gel mixture with an average particle size of 5 µm (HPTLC plates
Application volume: 5µL
Developing solvent system: Ethyl acetate, water, anhydrous formic acid, and glacial acetic acid (100:26:11:11)
Spray reagent 1: 5 mg/mL of 2-aminoethyl diphenylborinate in methanol
Spray reagent 2: 50 mg/mL of polyethylene glycol 400 in alcohol
Analysis
Samples: Standard solution and Sample solution Before development of the chromatograms, saturate the chamber for 20 min with Developing solvent system. Record temperature and humidity in the laboratory. If the relative humidity exceeds 50%, condition the plate to about 35% relative humidity using a suitable device. Apply the samples separately as bands to a suitable thin-layer chromatographic plate , and allow the bands to dry. Develop the plate oven at 1050 for 5 minute. Immediately spray the hot plate with spray reagent 1, then with spray reagent 2, dry, amd examine under long-wave length UV light.
Acceptance criteria: The Standard solution shows in its lower part with increasing RF values
a yellowish-brown fluorescent zone due to rutin (RF 0.28), a light blue fluorescent zone due
to chlorogenic acid (RF 0.36) and a yellow fluorescent zone due to quercetin (RF 0.92).
The Sample solution shows a yellowish -brown fluorescent zone, a light blue fluorescent zone
, and a yellowish brown fluorescent zone at RF similar to those of rutin, chlorogenic acid,
and quercetin, respectively, in the Standard solution. Additional yellowish to yellowish
green zones due to flavonoids detected in the Sample solution chromatogram include
one zone below the rutin and chlorogenic acid zones, Other zones may be seen in the
Sample solution chromatogram.
Heavy Metals : NMT 20µg/g
- Microbial Enumeration Tests
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.
Absence of Specified Micro Organisms
Meets the requirements of the tests for absence of Salmonella species and Escherichia coli.
- Loss On Drying
Sample : 1.0 g of finely powdered Ginkgo.
Analysis : Dry the Sample at 1050 for 2 h.
Acceptance criteria: NMT 11.0%
- Total Ash
Sample : 1.0 g of finely powdered Ginkgo.
Acceptance criteria: NMT 11.0%