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                        White Leadwort Root is the dried root of Plumbago zeylanica L. (Findlaya alba Bowdich, Plumbago lactea Salisb., P. scandens L., P. viscosa Blanco, Thela alba Lour.) (Family Plumbaginaceae), Herbarium Specimen Number: DMSC 5249, Crude Drug
Number: DMSc 1247.

Constituents  White Leadwort Root contains naphthoquinones (e.g., chitranone and plumbagin), alkaloids, coumarins, flavonoids, etc.

Description of the plant  (Fig. 1)  Herb or shrub up to 3 m tall; stem scandent or erect, cylindric, dark green, smooth, much branched. Leaves simple, alternate, ovate to ovate-oblong, 2.7 to 13 cm long, 1.2 to 5.8 cm wide, apex acute, acuminate, or mucronate, base obtuse or cuneate, margin entire, blade thin, glabrous, with whitish or greyish dots scattered on lower surface; petiole up to 1.5 cm long, with dilated amplexicaul base, occasionally auriculate. Inflorescences racemose, terminal, up to 30 cm long, usually branched; peduncle green, covered with sessile glandular hairs; rachis 2 to 8 cm long with glands; bract triangular to ovate, 0.3 to 1 cm long, 1.5 to 2.5 mm wide, apex acuminate, often with sessile glandular hairs outside. Flowers 3 to 70, 1 to 1.5 cm in diameter: calyx oblong, 0.9 to 1.2 cm long, tube short, about 2 mm in diameter, 5-ribbed, glandular, producing sticky exudate, lobes 5, narrowly triangular, 7.5 to 8 mm long, 0.8 to 1.2 mm wide; corolla white to bluish white, tube 1.1 to 2.3 cm long, lobes 5, obovate, 6.5 to 8 mm long, 2.7 to 3.5 mm wide; stamens 5, as long as corolla tube, filament free, about 1.2 mm long; anther oblong, about 1.3 mm long, violet; ovary superior, elliptic, 5-loculed, short-stalked, style glabrous. Fruit a capsule, horizontally dehiscent when mature, oblong, with 5 longitudinally furrows, pale yellow to brown, with remaining calyx. Seed 1, about 7 mm long, about 1.5 mm wide, apex acute, red-brown.

Description  Odour, mild and characteristic; taste, spicy.

                Macroscopical  (Fig. 1)  Roots, varied in length, 1 to 5 mm in diameter, somewhat twisted, longitudinally grooved, brown.

                Microscopical  (Figs. 2a, 2b)  Transverse section of the root shows periderm, cortex, and vascular tissue. Periderm: several layers of rectangular cork cells, some containing brown substances. Cortex: parenchyma, containing numerous starch grains, some containing brown substances. Vascular tissue: phloem and xylem; phloem comprising phloem rays, phloem fibres, and phloem parenchyma, containing numerous starch grains, some containing brown substances; xylem comprising xylem rays (some containing starch grains), xylem fibres, xylem parenchyma, some containing brown substances, and vessels.

                White Leadwort Root in powder possesses the diagnostic microscopical characters of the unground drug. The combination of ray cells containing numerous starch grains, cork, fibres, and starch grains is commonly seen.

Contra-indication  It is contra-indicated in pregnant women since it may cause miscarriage.

Packaging and storage  White Leadwort Root shall be kept in well-closed containers, protected from light, and stored in a dry place.

Identification

A. Macerate 1 g of the sample, in fine powder, with 10 mL of methanol for 30 minutes and filter. To 2 mL of the filtrate, add a few drops of ammonia TS: a pink colour is produced.

B. Carry out the test as described in the “Thin-Layer Chromatography” (Appendix 3.1), using silica gel GF254 as the coating substance and a mixture of 90 volumes of toluene and 10 volumes of ethyl acetate as the mobile phase and allowing the solvent front to ascend 8 cm above the line of application. Apply separately to the plate as bands of 5 mm, 10 μL of solution (A) and 2 μL of solution (B). Prepare solution (A) by macerating 1 g of the sample, in fine powder, with 5 mL of methanol for 30 minutes and filtering. For solution (B) dissolve 1 mg of plumbagin in 4 mL of methanol. After removal of the plate, allow it to dry in air and examine under ultraviolet light (254 nm), marking the quenching bands. The chromatogram obtained from solution (A) shows a quenching band (hRfvalue 80 to 85) corresponding to the plumbagin band from solution (B); other two quenching bands are also observed. Subsequently examine the plate under ultraviolet light (366 nm) through the cut-off filter; a band due to plumbagin is red fluorescent. One green, one blue, and one red fluorescent bands are also observed. Expose the plate to ammonia vapour; the band due to plumbagin is orange and another purple band is also observed (Fig. 3).

Loss on drying  Not more than 10.0 per cent w/w after drying at 105° to constant weight (Appendix 4.15).

Foreign matter  Not more than 2.0 per cent w/w (Appendix 7.2).

Acid-insoluble ash  Not more than 1.0 per cent w/w (Appendix 7.6).

Total ash  Not more than 7.0 per cent w/w (Appendix 7.7).

Water-soluble extractive  Not less than 4.0 per cent w/w (Appendix 7.12).

Ethanol-soluble extractive  Not less than 17.0 per cent w/w (Appendix 7.12).