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     Clinacanthus Nutans Leaf is the dried leaf of Clinacanthus nutans (Burm. f.) Lindau (Family Acanthaceae), Herbarium Specimen Number:  DMSC 5137, BKF 161293, Crude Drug Number:  DMSc 0727.

Constituents  Clinacanthus Nutans Leaf contains glycolipids, phaeophytins, triterpenoids, sterols, C-glycoside flavones, cerebrosides, sulfur-containing glucosides, etc.

Description of the plant  (Figs. 1a, 1b)  Scandent shrub 1 to 3 m tall, erect-drooping or clambering; branchlets finely pubescent.  Leaves simple, decussate, narrowly elliptic, oblong, ovate or lanceolate, 2.5 to 13 cm long, 0.5 to 3.5 cm wide, apex long-acuminate, base obtuse, rounded, or truncate, often oblique, margin exsculptate-dentate or subentire, pubescent on the nerves; petiole 3 to 15 mm long.  Inflorescence dense cyme, 5- to many-flowered, often terminating drooping-horizontal branches, resupinate; bracts narrow; calyx 5, deeply partite, segments narrow, about 1 cm long; corollas 5, glandular-pubescent, about 3.5 cm long, dull red with green base, corolla tube long-curved, widened upwards, bilabiate, lower lip 3-lobed (turned upwards) with yellow streaks, apically sordidly yellow or greenish yellow; stamens 2, inserted in the throat, subequalling the upper lip, anther 1-celled; ovary compressed, style filiform, shortly bidentate.  Fruit capsule, oblong, 4-seeded.

Description  Odour, characteristic.

         Macroscopical  (Fig. 1a)  A mixture of entire and broken, greenish brown to brown dried leaves. 

          Microscopical  (Figs. 2a, 2b, 2c)  Transverse section of the leaf shows upper epidermis,  a layer of rectangular cells, irregular and slightly wavy-walled in surface view; lithocysts, oblong; stomata absent with glandular and non-glandular trichomes.  Non-glandular trichome, multicellular uniseriate, 1- to 12-celled with warted walls.  Glandular trichome, unicellular stalk, 6- to 8-celled head.  Lower epidermis, almost similar to those of upper epidermis, slightly wavy-walled in surface view; diacytic stomata, numerous, lithocysts and glandular trichomes.  Mesophyll, a single layer of palisade cells and few layers of spongy cells, containing chloroplasts and globules of pale greenish yellow contents.  Underneath both epidermises, 3 to 4 layers of angular collenchymatous cells in the midrib.  Fibrovascular bundles composed of fibres, spiral vessels and xylem parenchyma. 

        Clinacanthus Nutans Leaf in powder possesses the diagnostic microscopical characters of the unground drug. 

Warning  It is not to be used on open wounds.

Additional information

       1. It should be used at the early signs or symptoms of inflammation or viral infection.

       2. Ethnomedically, it has been used topically as an anti-inflammatory and antiviral agents.  In these cases, 10 to 15 fresh or dried leaves, crushed and soaked with sufficient amount of ethanol (40 per cent) or Thai rice whiskey are applied directly to the affected areas as often as needed.  Fresh leaves are also applied directly after being crushed.

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

Identification

       A. Warm 1 g of the sample, in coarse powder, with 20 mL of water in a water-bath for 10 minutes and filter (solution 1).  To 2 mL of solution 1, add 1 drop of iron(III) chloride TS:  a brown precipitate is produced. 

       B. To 2 mL of solution 1, add 1 mL of potassium cupri-tartrate TS and warm the mixture  in a water-bath for a few minutes:  a brick red precipitate is produced.

       C. Warm 1 g of the sample, in coarse powder, with 20 mL of ethanol in a water-bath for 10 minutes and filter.  Evaporate 5 mL of the filtrate to dryness.  Dissolve the residue with 2 mL of acetic anhydride in a test-tube, and then slowly add 1 mL of sulfuric acid to form two layers:  a greenish brown ring develops at the zone between the two layers.

       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 80 volumes of ethyl acetate and 20 volumes of a 2 per cent v/v of glacial acetic acid in methanol as the mobile phase and allowing the solvent front to ascend 12 cm above the line of application.  Apply to the plate as a band of 10 mm, 10 μL of the test solution.  Prepare the test solution by macerating 2 g of the sample, in coarse powder, with 30 mL of a 70 per cent v/v solution of methanol overnight and filtering.  Wash 20 mL of the filtrate by shaking with three 20-mL portions of hexane, discard the washings and concentrate to 5 mL.  Add 15 mL of water and extract with three 20-mL portions of ethyl acetate.  Combine the ethyl acetate extracts and evaporate to dryness.  Dissolve the residue in 0.5 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.  Several bands are observed.  Examine the plate under ultraviolet light (366 nm) through the cut-off filter; several fluorescent bands of different colours are observed.  Spray the plate with phosphomolybdic acid TS and heat at 105° for 5 minutes.  Several bands of different colours are observed (Table 1); see also Fig. 3. 

         Repeat the same procedure on another plate.  After removal of the plate and allow it to dry in air.  Heat the plate at 80° for 10 minutes and then spray with natural products (NP) TS while the plate is still warm.  Subsequently spray the plate with polyethyleneglycol (PEG) TS and observe the colours of the bands under ultraviolet light (366 nm) through the cut-off filter within 5 to 15 minutes.  Several bands of different colours appear (Table 1); see also Fig. 3.

Loss on drying  Not more than 12.0 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 18.0 per cent w/w (Appendix 7.7).

Ethanol (50 per cent)-soluble extractive  Not less than 23.0 per cent w/w (Appendix 7.12).

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