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      Chebulic Myrobalan is the dried mature or nearly mature fruit of Terminalia chebula Retz. (Family Combretaceae), Herbarium Specimen Number:  DMSC 899.

Constituents  Chebulic Myrobalan contains tannins which are chebulinic acid, chebulic acid, tannic acid, gallic acid, etc.  It also contains β-sitosterol, saponins, and fixed oil.

Description of the plant  (Figs. 1a, 1b)  Medium-sized or large tree up to 30 m tall, up to 1.3 m in girth; bark rough, scaly; shoots and young leaves usually rus ty villous. Leaves simple, opposite, coriaceous, broadly ovate to ovate-elliptic, 8 to 15 cm long, 6 to 10 cm wide, glabrescent, nerves obscure above, slightly raised and usually brownish pubescent beneath, apex acute or abruptly acuminate, base cuneate, slightly cordate or rounded; petiole 1 to 3 cm long, glabrous or sparsely pubescent with a pair of nodular glands near leaf-base. Inflorescence axillary or terminal panicle, usually with 3 to 6 spikes; spike 3 to 6 cm long; rachis pubescent; flower 2 mm long, 3 to 4 mm in diameter; bract nearly glabrous, 1.5 to 2 mm long; calyx outside glabrous, inside densely villous, calyx-segment triangular;  stamen 3 to 4 mm long; ovary glabrous, ovoid, about 1 mm long; style glabrous, 2.5 to 3 mm long, disc lobed, densely villous. Fruit drupe, glabrous, subglobose to ellipsoid, 2.5 to 5 cm long, 1.5 to 2.5 cm wide, usually smooth or frequently 5-angulate ridged, wrinkled, turning blackish when dry. Seed 1, rough, ellipsoid, 1.5 to 2 cm long, 0.5 to 0.7 cm wide, without ridges.

Description  Odour, indistinct; taste, sour, slightly bitter and astringent.

     Macroscopical  (Fig. 1a)  Long ovoid to ovoid, 2.5 to 5 cm long, 1.5 to 2.5 cm wide;  externally yellowish brown to dark brown, slightly gross, 5 to 6 longitudinal ridges,  irregularly arranged wrinkles in the inter ridge.  The base marked by a circular scar, about  2 mm in diameter.  Seed 1, about 6 mm in diameter in the central part of hard endocarp.

      Microscopical  (Figs. 2a, 2b, 2c)  Transverse section of the fruit shows epicarp composed  of a layer of epidermal cells, the outer tangential wall and upper portion of the radial walls, thick.  Mesocarp, 2 to 3 layers of collenchyma followed by a broad zone of parenchyma in which fibres and sclereids, in group, and vascular bundles, scattered; fibres, simple-pitted walls, porous parenchyma; sclereids, various shapes and sizes, mostly elongated; tannins and aggregate crystals of calcium oxalate in parenchyma.  Endocarp consists of thick-walled sclereids of various shapes and sizes, mostly elongated.  Fibres, sclereids and vessels, lignified.  Testa, a layer of large cubical cells, followed by a zone of reticulate parenchyma and vessels; tegmen consists of collapse parenchyma.  Cotyledon folded and containing  aleurone grains, oil globules and some rosette aggregate crystals.

         Chebulic Myrobalan in powder possesses the diagnostic microscopical characters of the unground drug.

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

Identification

       A. Reflux 500 mg of the sample, in powder, with 15 mL of chloroform for 15 minutes, filter, and evaporate the filtrate to dryness.  Dissolve the residue in 2 mL of acetic anhydride, and then slowly add 1 mL of sulfuric acid to form two layers:  a brownish red ring with green upper layer forms.

       B. Complies with the tests for Identification B and C described under Belleric Myrobalan.

       C. Reflux 200 mg of the sample, in powder, with 10 mL of water for 5 minutes and filter. Transfer 1 mL of the filtrate to a test-tube and shake for a few minutes:  a persisting foam is  produced for over 30 minutes.

       D. Complies with the test for Identification E described under Belleric Myrobalan.   After removal of the plate, allow it to dry in air and examine under ultraviolet light (254 nm), marking the quenching spots.  The chromatogram obtained from solution (A) shows  a quenching spot (hR_f value 47 to 50) corresponding to the gallic acid spot from solution (B), and several spots of higher and lower hR_f value.  Spray the plate with anisaldehyde TS, heat at 105° for 5 minutes, and examine under ultraviolet light (366 nm); the spot due to gallic acid is purple and other two purple and one red fluorescent spots are observed (Table 1); see also Fig. 3. 

        Repeat the same procedure on another plate but spray with excess amount of potassium hexacyanoferrate(III) TS and then iron(III) chloride TS.  Observe immediately,  the chromatogram obtained from solution (A) shows a blue spot (hR_f value 47 to 50)  corresponding to the gallic acid spot from solution (B), other three blue and one white spots.  After standing overnight, another blue spot appears (Table 1); see also Fig. 3.

Table 1 hR_f Values of Components in Water Extract of the Fruits of Terminalia chebula Retz.

       *spot appears after standing overnight
       **gallic acid

Loss on drying  Not more than 11.0 per cent w/w after drying at 105° to constant weight (Appendix 4.15).

Acid-insoluble ash  Not more than 0.6 per cent w/w (Appendix 7.6). 

Total ash  Not more than 3.5 per cent w/w (Appendix 7.7).

Ethanol-soluble extractive  Not less than 20.0 per cent w/w (Appendix 7.12).

Ethanol (70 per cent)-soluble extractive  Not less than 29.0 per cent w/w (Appendix 7.12).

Water-soluble extractive  Not less than 28.0 per cent w/w (Appendix 7.12).

Tannins content  Not less than 14.0 per cent w/w (Appendix 7.21H).  Use 4 g of Chebulic Myrobalan, in powder, accurately weighed.

Foaming index  Not less than 170, when determined by the following method.

     Sample preparation  Transfer about 1 g of Chebulic Myrobalan, in coarse powder,  accurately weighed, into a 500-mL conical flask containing 100 mL of boiling water.  Maintain at moderate boiling for 30 minutes.  Cool, filter and dilute the filtrate with water to 100.0 mL.

     Procedure  Transfer Sample preparation into 10 stoppered test-tubes (16 mm x 16 cm) in a series of successive portions of 1, 2, 3, up to 10 mL and dilute each tube, if necessary, with water to 10 mL.  Stopper and shake in a lengthwise motion for 15 seconds, 2 frequencies per second.  Allow to stand for 15 minutes and measure the height of the foam.

     If the height of the foam in every tube is less than 1 cm, the foaming index is less than 100.

     If in any tube a height of foam of 1 cm is measured, the dilution in this tube (a) is the index sought. If this tube is the first or second tube in a series, it is necessary to have an intermediate dilution prepared in a similar manner to obtain a more precise result.
     If the height of the foam is more than 1 cm in every tube, the foaming index is over 1000.  In this case the determination needs to be made on a new series of dilutions of the Sample preparation in order to obtain a result

    Calculation

Foaming index = 1000/a,

           where a is the volume in ml of the Sample preparation used for preparing the dilution in the tube where foaming is observed.