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           Anise is the dried ripe fruit of Pimpinella anisum L. (Family Umbelliferae), Herbarium Specimen Number:  see Additional information 1, Crude Drug Number:  DMSc 0433.

Constituents  Anise contains volatile oil, of which trans-anethole is its major component with a small amount of estragole.  It also contains coumarins, flavonoids, fixed oils,  etc. 

Description of the plant  (Figs. 1a, 1b)  Annual herb 30 to 75 cm tall; stem erect, cylindrical, striated, pubescent.  Leaves heteromorphic, alternate below, opposite above; petiole 2 to 5 cm long, sheathing; basal leaves simple, reniform or broad-ovate, 1 to 3 cm long, 1.2 to 2.8 cm wide, margin coarse irregularly toothed, puberulent along veins; stem leaves 1- to 2-pinnate,  ultimate segments ovate or ovate-lanceolate, 6 to 7 mm long, 2 to 7 mm wide, 3-lobed, margin serrate or lacerate, leaves reduced upwards, becoming 3-lobed, lobe lanceolate or linear-lanceolate.  Inflorescence loose compound umbel, terminal and leaf-opposite, 1.6 to 6 cm across; peduncle 2.5 to 7 cm long.  Flower small; pedicel 1 to 5 mm long; sepal minute or wanting; petals 5, yellowish white, obcordate, abaxially pubescent; stamens 5, alternating with petals, inserted around an epigynous disk; ovary inferior, 2-loculed, 1-ovuled per  locule, stylopodium conic, styles 2.  Fruit cremocarp, oblong-ovoid, 3 to 6 mm long, 1 to  2.5 mm wide, greyish brown, densely appressed, short-hairy. 

Description  Odour, reminiscent of that of anethole; taste, sweet and aromatic.

      Macroscopical  (Fig. 1a)  Cremocarp ovoid or pyriform, slightly compressed laterally, greyish brown, 3 to 6 mm long, 1 to 2.5 mm wide; mericarp frequently separated, crescent- shaped, slightly pubescent.  Dorsal side convex, brown, with 5 longitudinal ridges and at the apex with a short conical stylopodium; commissural side concave, brown, with persisting carpophore and pedicel. 

     Microscopical  (Figs. 2a, 2b)  Transverse section of the mericarp through the cotyledon shows epicarp, mesocarp, endocarp, spermoderm, endosperm, and cotyledon.  Epicarp,  a layer of epidermal cells with numerous papillae and usually unicellular trichomes, covered with striated cuticle, generally 6-ridged.  Mesocarp, 3 or 4 layers of elongated parenchyma cells, with a small lignified fibrovascular bundle under the ridge; vittae, elliptic, brown, surrounded by small epithelial secretory cells, (15–)30 to 35(–45) small vittae forming a line along the dorsal side and 2 large vittae in the commissural side.  Endocarp, a layer of  elongated thin-walled cells.  Spermoderm, attached to the endocarp, consisting of a layer of elongated cells with some collapsed cells.  Endosperm, thick-walled polygonal cells  containing oil globules and aleurone grains with microcrystals.  Cotyledon, thin-walled cells containing oil globules and aleurone grains. 

          Anise in powder possesses the diagnostic microscopical characters of the unground drug.

Warning  It should be used with caution in pregnant and nursing women. 

Additional information

       1. Anise plant is not native to nor commercially cultivated in Thailand.  The plant yielding anise fruit is here referred to the herbarium specimen, collector’s number Kruijt 245, deposited at the National Herbarium of the Netherlands (L), Leiden, the Netherlands. The photographic illustration of the specimen can be seen at the Department of Medical Sciences Herbarium (DMSC), Nonthaburi, Thailand.

2. It is commonly used with other herbal drugs in Thai traditional herbal preparations. 

Packaging and storage  Anise 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. Boil 500 mg of the sample, in powder, with 10 mL of water in a water-bath for 10 minutes and filter.  To 2 mL of the filtrate, add 1 or 2 drops of a 1 per cent w/v solution of iron(III) chloride:  a greenish brown colour develops.

       B. Mix 1 g of the sample, in powder, with 3 mL of ethanol, shake for 5 minutes and filter. To 1 mL of the filtrate, add 1 mL of dinitrophenylhydrazine TS1:  an orange-yellow solution is produced.

       C. Add 5 mL of chloroform to 500 mg of the sample, in powder, shake well, set aside for 30 minutes, and filter.  Allow 0.1 mL of the filtrate to dry and add a few drops of a 5 per cent w/v solution of vanillin in sulfuric acid:  a reddish brown colour develops and changes to red and to purple, consecutively.

       D.   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.  Apply separately to the plate, 2 μL each of solutions (A), (B) and (C).  Prepare solution (A) by shaking 2 g of sample, in fine powder, with 5 mL of ethyl acetate for 3 minutes and filtering.  For solution (B), add 5 μL of anethole to 1 mL of ethyl acetate and mix.  For solution (C), add 2 μL of olive oil to 1 mL of ethyl acetate and mix.  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 65 to 66) corresponding to the anethole spot from  solution (B).  Spray the plate with vanillin-sulfuric acid TS and heat at 110° for 10 minutes; the spot due to anethole is brownish purple.  One violet spot (hR_f value 74 to 76) corresponds to the triglycerides of olive oil from solution (C).  Several other spots are also observed  (Table 1); see also Fig. 3.

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

Foreign matter  Not more than 6.0 per cent w/w (Appendix 7.2).

Acid-insoluble ash  Not more than 2.5 per cent w/w (Appendix 7.6).

Total ash  Not more than 12.0 per cent w/w (Appendix 7.7).

Ethanol-soluble  extractive  Not less than 10.0 per cent w/w (Appendix 7.12).

Volatile oil  Not less than 1.0 per cent v/w,  calculated on the anhydrous basis (Appendix 7.3H).  Use 20 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 2 to 3 mL per minute for 4 hours.  Use 1.0 ml of xylene in the graduated tube.

Dose  0.5 to 1.0 g three times a day.