Bai Shao

PAEONIAE RADIX ALBA (白芍, Baishao) White Peony Root (Fam. Ranunculaceae) The drug is collected in summer or autumn, washed clean, removed from both ends and the rootlets, either peeled after boiling in water or boiled after peeling, and dried in the sun. Description Cylindrical, straight or slightly curved, both ends truncate, 5–18 cm long and 1–2.5 cm in diameter. Externally whitish or pale brownish-red, glossy or with longitudinal wrinkles, rootlet scars, and occasional remnants of brown cork. Texture compact and not easily broken. Fracture relatively even, whitish or pale brownish-red. Cambium ring distinct. Medullary rays arranged radially. Odour slight; taste slightly bitter and sour. Identification (1) Powder Yellowish-white. Masses of gelatinized starch granules abundant. Clusters of calcium oxalate 11–35 μm in diameter, enclosed in parenchymatous cells, often arranged in rows or several occurring within one cell. Bordered-pitted or reticulate vessels 20–65 μm in diameter. Fibres long fusiform, 15–40 μm in diameter, with thickened, slightly lignified walls and conspicuous round pits. (2) Shake 0.5 g of the powder with 10 mL of ethanol for 5 minutes and filter. Evaporate the filtrate to dryness. Dissolve the residue in 1 mL of ethanol as the test solution. Dissolve Paeoniflorin CRS in ethanol to prepare a solution containing 1 mg/mL as the reference solution. Carry out the method for Thin-Layer Chromatography (0502), using silica gel G as the coating substance and a mixture of chloroform, ethyl acetate, methanol, and formic acid (40:5:10:0.2) as the mobile phase. Apply separately 10 μL of each solution to the plate. After development, remove the plate, dry in air, spray with 5% vanillin in sulfuric acid solution, and heat until the spots become distinct. The bluish-purple spot in the chromatogram obtained with the test solution corresponds in position and colour to that obtained with the reference solution. Water Not more than 14.0% (0832, Method 2). Total Ash Not more than 4.0% (2302). Heavy Metals and Harmful Elements Carry out the methods for determination of lead, cadmium, arsenic, mercury, and copper (2321, Atomic Absorption Spectrophotometry or Inductively Coupled Plasma Mass Spectrometry). Limits: Lead: ≤ 5 mg/kg Cadmium: ≤ 1 mg/kg Arsenic: ≤ 2 mg/kg Mercury: ≤ 0.2 mg/kg Copper: ≤ 20 mg/kg Residue of Sulfur Dioxide Carry out the method for determination of residual sulfur dioxide (2331). Not more than 400 mg/kg. Extractives Carry out the method for determination of water-soluble extractives (2201, Hot Maceration Method). Not less than 22.0%. Assay Carry out the method for High-Performance Liquid Chromatography (0512). Chromatographic system and system suitability Use octadecylsilane-bonded silica gel as the stationary phase. Use a mixture of acetonitrile and 0.1% phosphoric acid (14:86) as the mobile phase. Detection wavelength: 230 nm. The number of theoretical plates shall be not less than 2000, calculated with reference to the paeoniflorin peak. Reference solution Accurately weigh an appropriate quantity of Paeoniflorin CRS. Dissolve in methanol to prepare a solution containing 60 μg/mL. Test solution Accurately weigh 0.1 g of the powder into a 50 mL volumetric flask. Add 35 mL of dilute ethanol. Ultrasonicate (240 W, 45 kHz) for 30 minutes. Cool and dilute to volume with dilute ethanol. Mix well, filter, and use the subsequent filtrate as the test solution. Procedure Inject accurately 10 μL of the reference solution and the test solution into the chromatograph. Determine and calculate the content. The drug contains not less than 1.6% of paeoniflorin (C₂₃H₂₈O₁₁), calculated with reference to the dried drug. Prepared Slices Processing Paeoniae Radix Alba Wash clean. Soften thoroughly. Cut into thin slices. Dry. Description Subrounded thin slices. Outer surface pale brownish-red or whitish. Cut surface whitish or slightly pale brownish-red. Cambium ring distinct. Vascular bundles slightly raised and arranged radially. Odour slight. Taste slightly bitter and sour. Identification As required for the crude drug. Water, Total Ash, Residual Sulfur Dioxide, and Extractives As required for the crude drug. Assay Contains not less than 1.2% of paeoniflorin (C₂₃H₂₈O₁₁), following the method for the crude drug.