Chuan Wu (Zhi)

ACONITI RADIX (川乌, Chuanwu) Common Monkshood Mother Root The dried mother root of Aconitum carmichaelii Debx. (Fam. Ranunculaceae). The drug is collected from late June to early August, removed from the daughter roots, fibrous roots, and soil, and dried in the sun. Description Irregularly conical, slightly curved, 2–7.5 cm long and 1.2–2.5 cm in diameter. The apex usually bears stem remnants. The middle portion is commonly swollen on one side. Externally brown or greyish-brown, shrivelled, with tuberculate rootlets and scars of detached daughter roots. Texture compact. Fracture whitish or pale greyish-yellow. Cambium ring polygonal. Odour slight. Taste pungent and numbing. Identification (1) Transverse section Metaderm consisting of brown suberized cells. Stone cells occasionally present in the cortical parenchyma, solitary or in groups, subrectangular, square or elongated, with large lumina. Endodermis indistinct. Groups of sieve tubes scattered throughout the phloem. Phloem fibres occasionally present in the inner phloem. Cambium ring subpolygonal. One or more abnormal vascular bundles may occur inside or outside the cambium ring. Xylem vessels arranged in several radial rows or in a V-shaped pattern. Pith distinct. Parenchymatous cells filled with starch granules. Powder Greyish-yellow. Simple starch granules spherical, rounded-elliptic or reniform, 3–22 μm in diameter. Compound starch granules composed of 2–15 components. Stone cells nearly colourless or pale yellowish-green, subrectangular, subsquare, polygonal or obliquely elongated, 49–117 μm in diameter and 113–280 μm long. Cell walls 4–13 μm thick. Thick-walled stone cells distinctly striated with sparse pits. Metaderm cells brown, with unevenly thickened walls; some show wart-like projections extending into the lumen. Bordered-pitted vessels predominate, pale yellow, 29–70 μm in diameter. The vessel ends are truncate or acute. Perforations occur on the terminal or lateral walls. Some vessel elements are short, thick, tortuous, or interconnected vertically and horizontally. (2) Moisten 5 g of the powder with 2 mL of Ammonia TS. Add 30 mL of ether. Ultrasonicate for 30 minutes. Filter. Evaporate the filtrate to dryness. Dissolve the residue in 1 mL of dichloromethane as the test solution. Dissolve Aconite Diester-Alkaloids Reference Extract in a mixture of isopropanol and chloroform (1:1) to prepare a solution containing 3 mg/mL of each alkaloid as the reference extract solution. Carry out the method for Thin-Layer Chromatography (0502) using silica gel G as the coating substance and a mixture of n-hexane, ethyl acetate, and methanol (6.4:3.6:1) as the mobile phase. Apply separately 10 μL of the test solution and reference extract solution to the plate. Develop the plate in a chamber pre-equilibrated with ammonia vapour for 20 minutes. Remove the plate and dry in air. Spray with dilute potassium iodobismuthate TS. The spots obtained with the test solution correspond in position and colour to those obtained with the reference extract solution.