Ban Zhi Lian

SCUTELLARIAE BARBATAE HERBA (半枝莲, Banzhilian) Barbated Skullcap Herb The drug is collected in summer and autumn when the aerial parts are growing luxuriantly, washed clean, and dried in the sun. Description Herb 15–35 cm long, glabrous or sparsely pubescent on the floral axis. Roots slender. Stems fascicled, relatively slender, quadrangular, externally dark purple or brownish-green. Leaves opposite, shortly petiolate; lamina mostly crumpled; when entire, triangular-ovate or lanceolate, 1.5–3 cm long and 0.5–1 cm wide; apex obtuse; base broadly cuneate; margins entire or indistinctly crenate. Upper surface dark green; lower surface greyish-green. Flowers solitary in the leaf axils of the upper branches. Calyx lobes obtuse or slightly rounded. Corolla bilabiate, brownish-yellow or pale bluish-purple, about 1.2 cm long, pubescent. Fruits oblate, pale brown. Odour slight; taste slightly bitter. Identification (1) Transverse section of stem Stem subsquare. Epidermis consists of one layer of subrectangular cells covered with a cuticle. Stomata and glandular scales visible. At the four ridges, 2–4 layers of lignified fibres occur beneath the epidermis. Cortex composed of subrounded parenchymatous cells. Endodermis one cell layer. Pericyclic fibres occur singly or in groups of 2–12, arranged in an interrupted ring and especially dense at the four corners. Vascular bundles collateral and well developed beneath the four ridges. Phloem narrow. Cambium forms a continuous ring. Xylem composed of vessels, fibres, and parenchyma. Pith broad, consisting of subrounded parenchymatous cells of varying size; pits visible; the centre often hollow. Powder of leaf Greyish-green. Epidermal cells irregular, with sinuous anticlinal walls. Stomata diacytic or anomocytic. Glandular scales with 4–8-celled heads, 24.5–38.5 μm in diameter and about 25 μm high; stalk unicellular. Non-glandular hairs 1–3 (occasionally 5)-celled, apex curved, 60–319 μm long, walls warty, base showing radial striations. Glandular hairs infrequent, with 1–4-celled heads and 1–4-celled stalks, approximately 80 μm long. (2) To 1 g of the powder add 30 mL of methanol. Ultrasonicate for 40 minutes and filter. Evaporate the filtrate to dryness. Dissolve the residue in 1 mL of methanol as the test solution. Prepare a solution of 1 g of Scutellariae Barbatae Herba Reference Drug in the same manner as the reference drug solution. Dissolve Luteolin CRS and Apigenin CRS separately in methanol to prepare solutions containing 1 mg/mL. Carry out the method for Thin-Layer Chromatography (0502) using silica gel G as the coating substance and a mixture of toluene, ethyl formate, and formic acid (3:3:1) as the mobile phase. Apply separately 1 μL of each of the four solutions to the plate. After development, remove the plate and dry in air. Spray with 1% aluminium chloride in ethanol. Heat at 105°C for several minutes. Examine under ultraviolet light (365 nm). The fluorescent spots in the chromatogram obtained with the test solution correspond in position and colour to those obtained with the reference drug solution and the reference solutions. Foreign Matter Not more than 2.0% (2301). Water Not more than 12.0% (0832, Method 2). Total Ash Not more than 10.0% (2302). Acid-insoluble Ash Not more than 3.0% (2302). Extractives Carry out the method for determination of water-soluble extractives (2201, Hot Extraction Method). Not less than 18.0%. Assay Total Flavones Reference solution Accurately weigh Scutellarin CRS. Dissolve in methanol to prepare a solution containing 0.2 mg/mL. Standard calibration Transfer accurately 0.4, 0.8, 1.2, 1.6, and 2.0 mL of the reference solution into separate 25 mL volumetric flasks. Dilute to volume with methanol. Carry out the method for Ultraviolet–Visible Spectrophotometry (0401). Using methanol as the blank, measure the absorbance at 335 nm. Plot the calibration curve using absorbance as the ordinate and concentration as the abscissa. Procedure Accurately transfer 1 mL of the methanol solution obtained under Assay—Scutellarin, extracted with a Soxhlet extractor and diluted to 100 mL, into a 50 mL volumetric flask. Dilute to volume with methanol. Measure the absorbance as described above. Calculate the total flavone content from the calibration curve. The drug contains not less than 1.50% of total flavones, calculated as Scutellarin (C₂₁H₁₈O₁₂), with reference to the dried drug. Scutellarin Carry out the method for High-Performance Liquid Chromatography (0512). Chromatographic system and system suitability Use octadecylsilane-bonded silica gel as the stationary phase. Mobile phase: Methanol : Water : Acetic Acid = 35 : 61 : 4 Detection wavelength: 335 nm The number of theoretical plates shall be not less than 1500, calculated with reference to the scutellarin peak. Reference solution Accurately weigh Scutellarin CRS. Dissolve in the mobile phase to prepare a solution containing 80 μg/mL. Test solution Accurately weigh about 1 g of the powder (through No. 3 sieve). Defat with petroleum ether (60–90°C) in a Soxhlet extractor until the extract becomes colourless. Discard the petroleum ether extract. Evaporate residual petroleum ether. Extract with methanol under reflux until colourless. Transfer the methanol extract to a 100 mL volumetric flask. Dilute to volume with methanol. Transfer accurately 25 mL of this solution. Evaporate to dryness. Dissolve the residue in 20% methanol. Transfer to a 25 mL volumetric flask. Dilute to volume. Filter. 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 0.20% of Scutellarin (C₂₁H₁₈O₁₂), calculated with reference to the dried drug. Prepared Slices Processing Remove foreign matter. Wash clean. Cut into sections. Dry. Description Irregular sections. Stems quadrangular and hollow. Outer surface dark purple or brownish-green. Leaves opposite, mostly broken. Upper surface dark green; lower surface greyish-green. Calyx lobes obtuse or slightly rounded. Corolla bilabiate, brownish-yellow or pale bluish-purple. Fruits oblate, pale brown. Odour slight. Taste slightly bitter. Identification As required for the crude drug, except for the transverse section of the stem. Water, Total Ash, Acid-insoluble Ash, and Extractives As required for the crude drug. Assay As required for the crude drug. Property and Flavor Cold; pungent and bitter. Meridian Tropism Lung, Liver, and Kidney meridians. Actions To clear heat, remove toxins, resolve blood stasis, and promote urination. Indications Carbuncles, boils, sores, swelling and toxic conditions, sore throat, traumatic pain, edema, jaundice, and bites from insects, worms, or snakes. Administration and Dosage 15–30 g. Storage Preserve in a dry place.