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         Ginger is the dried rhizome of Zingiber officinale Roscoe (Amomum zingiber L.) (Family Zingiberaceae), Herbarium Specimen Number: BKF 193777, Crude Drug Number: DMSc 1145.

Constituents Ginger contains oleoresin predominantly consisting of gingerols, shogaols and volatile oil. Its volatile oil comprises zingiberene, borneol, geraneol, etc. It also contains fatty acids, starch, etc. 

Description of the plant (Figs. 1a, 1b) Perennial herb; pseudostem up to 2 m tall, leafy; subterraneous rhizome branched, thick, fleshy, yellowish inside, strongly aromatic. Leaves simple, alternate, sessile, lanceolate or linear-lanceolate, 10 to 30 cm long, 1.5 to 3 cm wide, apex acute or acuminate, base obtuse, sheathing; ligule membranous, 2 to 4 mm long, bilobed. Inflorescence arising from rhizome, spike elliptic to oblong, 4 to 9 cm long, 2 to 3 cm wide; peduncle erect, up to 25 cm long, with 5 to 9 green sheaths; bract imbricate, free, green, incurved, globose, obrhombic or obovate, 2 to 3 cm long, 2 to 2.5 cm wide, apex obtuse, glabrous on both sides, cream to creamy yellow on margin and tip, sharp apex tip; bracteole elliptic-oblong, cirrated, 2.5 to 2.8 cm long, 1 to 1.5 cm wide, apex obtuse or teethed, glabrous; corolla tube 3-lobed, 2.2 to 2.5 cm long, glabrous, white, dorsal lobe 1.7 to 1.8 cm long, about 8 mm wide, lateral lobes 1.6 to 1.7 cm long, 4 to 5 mm wide; labellum conspicuously 3-lobed, midlobe rounded or obovate, about 1.6 cm long, 1.3 to 1.4 cm wide, apex truncate or emarginate, dark red with yellow blotches at base, side lobes about 7 mm long, 5 to 6 mm wide, apex acute, dark red with scattered creamy dots; anther about 1 cm long, about 3 mm wide, filament about 3 mm long, flattened, appendage 7 to 9 mm long, apex acute, dark red; stylode unequal, 7 to 8 mm long; ovary inferior, glabrous, 3-loculed, each locule with several ovules. Fruit capsule, oblong. Seeds numerous, blackish, arillate.

Description Odour, characteristic and aromatic; taste, pungent and aromatic

          Macroscopical (Fig. 1a) Unpeeled, horizontal, irregularly branched and vary in size. Externally light brown with longitudinal wrinkles and distinct annulated nodes; branched parts usually with remains of scale leaves, apex with stem scars or buds. Texture compact, fibrous; fracture yellowish to brownish.

          Microscopical (Figs. 2a, 2b) Transverse section of the rhizome shows epidermis, storied cork, cortex, pseudoendodermis, and vascular bundles. Epidermis, a layer of thin-walled rectangular cells. Storied cork, layers of thin-walled, suberinized rectangular cells. Cortex, thin-walled parenchyma cells containing numerous starch grains and/or oil globules, some of which containing yellow oleoresin. Pseudoendodermis, a layer of small thin-walled rectangular cells. Vascular bundles, scattered in cortex, containing xylem and phloem tissues; vessels, mostly scalariform and reticulate.

          Ginger in powder possesses the diagnostic microscopical characters of the unground drug. Layers of thin-walled cells of storied cork, parenchyma containing starch grains, and/ or altered starch, and/or yellow oleoresin are characteristic.

Warning

1. It should not be used in children under 6 years of age and in pregnant women.

2. It should not be used in patients with bile duct obstruction except under medical supervision.

3. Concomitant use with anticoagulants and antiplatelets should be used with caution.

Additional information Ginger containing not less than 2 per cent v/w of volatile oil can be administered orally as an anti-emetic.

Packaging and storage Ginger shall be kept in well-closed containers, preferably of metal or glass, protected from light and stored in a cool and dry place.

Identification

          A. Dissolve 50 mg of the residue obtained from Ethanol-soluble extractive in 25 mL of water and extract this solution with two 15-mL portions of ether. Combine the ether extracts and evaporate to dryness. To the residue, add 5 mL of a 75 per cent v/v solution of sulfuric acid, and 5 mg of vanillin and then mix well. Allow to stand for 15 minutes and add 5 mL of water: a bright blue colour develops.

          B. To 1 g of the sample, in powder, add 5 mL of a 50 per cent v/v solution of glacial acetic acid. Shake vigorously for 15 minutes and filter. To the filtrate, add a few drops of ammonium oxalate TS: a slight turbidity is produced.

          C. 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 40 volumes of hexane and 60 volumes of ether as the mobile phase. Apply separately to the plate as bands of 15 mm, 20 μL each of the following two solutions. Prepare solution (A) by shaking 1 g of the sample, in powder, with 5 mL of methanol for 15 minutes and filtering. For solution (B), dissolve 10 μL of citral and 10 mg of resorcinol, as the reference compounds¹, in 10 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 three quenching bands. Two quenching bands are between the bands due to resorcinol (hR_f value 30 to 33) and citral isomers (hR_f values 70 to 72 and 73 to 75) in the chromatogram obtained from solution (B) and one quenching band is below the resorcinol band. Examine the plate under ultraviolet light (366 nm) through the cut-off filter; one blue and several green-blue fluorescent bands are observed. Spray the plate with vanillin-sulfuric acid TS2 and heat at 105° for 10 minutes. The chromatogram obtained from solution (A) shows one violet-grey, one brown-yellow and two violet bands below the red band due to resorcinol in the chromatogram obtained from solution (B). It also shows one dark violet band above the two violet bands due to citral isomers in the chromatogram obtained from solution (B) and two violet-grey and two violet bands between the bands due to resorcinol and citral isomers (Table 1); see also Fig. 3.

¹Citral and Resorcinol are not marker compounds for Ginger. They are used as the reference compounds for the purpose of TLC identification.

Table 1 hR_f Values of Components in Methanolic Extract of the Rhizomes of Zingiber officinale Roscoe

Water Not more than 11.0 per cent v/w (Azeotropic Distillation Method, Appendix 4.12).

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 10.0 per cent w/w (Appendix 7.7).

Water-soluble ash Not less than 3.0 per cent w/w (Appendix 7.11).

Ethanol-soluble extractive Not less than 5.0 per cent w/w (Appendix 7.12).

Water-soluble extractive Not less than 13.0 per cent w/w (Appendix 7.12).

Volatile oil Not less than 0.8 per cent v/w, calculated on the anhydrous basis (Appendix 7.3H). Use 50 g, in coarse powder, freshly prepared and accurately weighed. Use 200 mL of water as the distillation liquid and a 500-mL round-bottomed flask. Distil at a rate of 3 mL per minute for 5 hours. Use 2.0 mL of xylene in the graduated tube.

Dose 2 to 4 g a day