Pygeum consists of the bark of Prunus africana (Hook f.) Kalkman (Pygeum africanum Hook f.) (Fam. Rosaceae). It contains NLT 9.0% of extractable matter.
•  A. Thin-Layer Chromatographic Identification Test
Standard solution A:  10 mg/mL of USP Pygeum Extract RS in chloroform
Standard solution B:  1 mg/mL of USP -Sitosterol RS in chloroform
Sample solution:  Transfer 10 g of the powdered plant material to a soxhlet apparatus. Extract with 150 mL of methylene chloride for 4 h. Evaporate the extract under vacuum to dryness. Dissolve the residue with 10 mL of methylene chloride.
Chromatographic system 
Adsorbent:  0.25-mm layer of chromatographic silica gel
Application volume:  10 µL
Developing solvent system:  Methylene chloride in a saturated chamber
Spray reagent:  Sulfuric acid and water (1:1)
Samples:  Standard solution A, Standard solution B, and Sample solution
Develop the chromatograms to a length of NLT 15 cm, and dry the plate in a current of air. Spray the plate with Spray reagent, and heat the plate at 100 for 10 min. Examine the plate under white light.
Acceptance criteria:  The chromatogram obtained with the Sample solution shows one red-violet zone turning to grayish-brown near the origin that corresponds in color and RF value to that in the chromatogram of Standard solution A; one red-violet zone turning to grayish-brown at an RF about 0.08, corresponding in color and RF value to that in the chromatogram of Standard solution B; above these spots a grayish-brown zone may be present, corresponding in color and RF value to that in the chromatogram of Standard solution A. Other colored zones of varying intensities may be observed in the chromatogram of the Sample solution.
•  Extractable Matter
Analysis:  Extract 2.00 g of the powdered material in a soxhlet apparatus with 150 mL of alcohol for 6 h. Evaporate the solution to dryness under vacuum, and dry the residue at 105 for 24 h.
Acceptance criteria:  NLT 9.0% of extractable matter
•  Heavy Metals 231: NMT 20 µg/g
•  Botanic Characteristics
Macroscopic:  Bark pieces consist of long fragments of variable dimensions, from only a few cm to 1 m long with a thickness varying from a few mm to 1–2 cm. The color is brown, more or less dark on the external surface; light brown to red-brown on the internal surface. The external part of the bark presents a very dark and fissured rhytidome that in the samples of old trees is fragmented in more or less square plaques of about 1–5 cm. The thickness varies from 1 mm in young plants or branches to 5–8 mm in old plants. The outer surface may also be covered with whitish lichens or thin filamentous moss. The internal bark, under the rhytidome, is clearer and has a more reddish coloration, with a long fibrous break, from reddish to light brown and dark brown in color, often presenting concentric stratification cracks. The internal surface is clearer and presents small wrinkles.
Microscopic:  The transverse section of the bark presents a suberized bed having a thickness depending on the age of the plant, consisting of multiple layers of small, square cells with the walls of moderate thickness. It presents a cortical parenchyma of more or less round cells, with a few apparent formations of very thin-walled sclereids, definitely sharp. Often, in the parenchyma, there are groups of cells containing oxalate druses; a few bigger cells with highly thickened walls can also be observed. It shows a liber with phloem zones and presenting medullary rays. The phloemical portions contain groups of fibrous cells with highly thickened walls as well as phloemical and parenchymal elements, sometimes containing druses of oxalate. The medullary rays are of conical shape, larger on the external surface and thinner on the internal side; they can also contain druses of oxalate.
•  Loss on Drying 731: Dry at 60 for 15 h: it loses NMT 10.0% of its weight.
•  Packaging and Storage: Preserve in well-closed containers, and store at room temperature.
•  Labeling: The label states the Latin binomial and, following the official name, the parts of the plant contained in the article.
•  USP Reference Standards 11
USP Pygeum Extract RS
USP -Sitosterol RS Click to View Structure
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