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                        Indian Leadwort Root is the dried root of Plumbago indica L. (P. rosea L., Thela coccinea Lour.) (Family Plumbaginaceae), Herbarium Specimen Number: DMSC 5248, Crude Drug Number: DMSc 0978.

Constituents  Indian Leadwort Root contains naphthoquinones (e.g., plumbagin), flavonoids, etc.

Description of the plant  (Fig. 1)  Perennial herb, up to 2 m tall; stem erect or scandent, branching from base; young shoot reddish or reddish green; bark smooth; root woody, tan outside, whitish inside. Leaves simple, alternate or fascicled, narrowly ovate, elliptic-ovate or elliptic, 4 to 16.5 cm long, (0.8‒)2 to 7.6 cm wide, apex obtuse to acute, often mucronate, base rounded to obtuse, margin entire, papery, often twisted; petiole and rachis reddish when young, glandular hairs. Inflorescence spicate-racemose, terminal, up to 50 cm long, hardly branched; peduncle 1 to 3 cm long; rachis (8‒)10 to 40(‒50) cm long, glabrous; bract ovate, 2 to 4.5 mm long, 1.2 to 2 mm wide, apex acuminate; bracteole ovate to elliptic, 2 to 3 mm long, 1.2 to 2 mm wide, apex acute. Flowers (20‒)35 to 90: calyx red, tube oblong, about 1 cm long, about 2 mm wide, stalked sticky glandular hairs, lobes 5, narrowly triangular, about 8 mm long, about 1 mm wide; corolla pinkish, bright red, or dark red, tube 2 to 3.5 cm long, about 2 cm wide, lobes 5, obovate, about 1 cm long, about 7 mm wide, apex rounded and mucronate; stamen attached to upper part of corolla tube, free part of filament about 1 mm long, light pink, anther oblong, about 2 mm long; ovary superior, ellipsoid-ovoid, indistinctly angular, 1-locular with 1 ovule, style basally hairy, stigmas 5, with small capitate papillae above. Fruit a capsule, ellipsoid, included in persistent calyx and (often twisted) corolla, pericarp thin, circumscissile near base. Seed 1.

Description  Odour, characteristic; taste, bitter and spicy.

                        Macroscopical  (Fig. 1)  Roots, varied in length, 1 to 4 mm in diameter, occasionally with rootlets; longitudinally wrinkled, dark brown to blackish brown.

                        Microscopical  (Figs. 2a, 2b)  Transverse section of the root shows periderm, cortex, and vascular tissue. Periderm: rectangular cork cells, some containing brown substances. Cortex: collenchyma and thin-walled parenchyma, some containing yellow substances and/or brown substances. Vascular tissue: phloem and xylem; phloem comprising phloem rays, and phloem parenchyma, some containing yellow substances and/or brown substances; xylem comprising xylem rays, xylem fibres, xylem parenchyma, some containing brown substances, and vessels.

                Indian Leadwort Root in powder possesses the diagnostic microscopical of the unground drug. Collenchyma associated with cork and fibre with several connecting pores can be unique in characters.

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

Packaging and storage  Indian 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 (hRf value 67 to 71) corresponding to the plumbagin band from solution (B); other three 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, three blue, and three red fluorescent bands are also observed. Expose the plate to ammonia vapour; the band due to plumbagin is purple and two purple bands are 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 2.0 per cent w/w (Appendix 7.6).

Total ash  Not more than 10.0 per cent w/w (Appendix 7.7).

Water-soluble extractive  Not less than 22.0 per cent w/w (Appendix 7.12).

Ethanol-soluble extractive  Not less than 14.0 per cent w/w (Appendix 7.12).