สารบัญ

Thai name  ลำโพงฝรั่ง  (LAMPHONG FA-RANG)

Category  Anticholinergic; antispasmodic.

             Stramonium consists of the dried leaf or the dried leaf, flowering tops and occasionally fruits of Datura stramonium L. and its varieties (Family Solanaceae).  It contains not less than 0.25 per cent of total alkaloids, calculated as hyoscyamine with reference to the material dried to constant weight at 100° to 105°.  The alkaloids consist mainly of those of the hyoscyamine-atropine group together with hyoscine.

Origin of plant  Stramonium is native to Central America and the Caribbean.

Constituents  Stramonium contains alkaloids, predominantly hyoscyamine, hyoscine and atropine.  It also contains flavonoids, coumarins, tannins, and glycosides.

Description  Odour unpleasant; taste bitter.
Macroscopical  Leaf dark brownish green or dark greyish green, ovate or triangular-ovate, apex acuminate, base often unequal, margin dentate, pubescent along veins when young, becoming nearly glabrous with aged, much twisted and shrunken during drying, thin and brittle; petiole short.  Stem green or purplish green, slender, curved and twisted, longitudinally wrinkled, sometimes transversely wrinkled, dichasially branched, with a single flower or an immature fruit in the fork.  Flower:  calyx 5-lobed, gamosepalous, 5-lobed; corolla brownish white or purplish, trumpet-shaped; pedicel short.  Fruit a capsule, usually covered with numerous short, stiff emergences; seeds brown or black with minutely pitted testa.
Microscopical  Powdered drug of the leaf shows fragments of upper and lower epidermises in surface view, anisocytic and anomocytic stomata, fragments of covering trichomes, glandular trichomes, mesophyll, fragments of spongy parenchyma, fibres and reticulate vessels of stems, pollen grains, fragments of corolla, and fragments of seeds.  Fragments of upper and lower epidermises in surface view:  slightly wavy anticlinal-walled cells and smooth cuticle accompanied by palisade and spongy parenchyma.  Anisocytic and anomocytic stomata present more frequently in lower epidermis.  Fragments of covering trichomes conical, uniseriate, with 3 to 5 warty-walled cells, some of which collapsed.  Glandular trichomes short and clavate, with 2- to 7-celled heads.  Mesophyll, in transverse view, dorsiventral, consisting of a single layer of palisade cells and a spongy parenchyma containing cluster of calcium oxalate crystals.  Fragments of spongy parenchyma, some containing small clusters of calcium oxalate crystals associated with annularly and spirally thickened vessels, in surface view.  Pollen grains, subspherical.  Fragments of corolla:  wavy-walled cells and underlying mesophyll, some containing prismatic or cluster crystals of calcium oxalate.  Fragments of seeds containing yellowish-brown sinuous, thick-walled sclereids of testa and, occasionally, prismatic and microsphenoidal crystals of calcium oxalate.

Other relevant information  It should be used with caution in patients with CNS depressants.

Packaging and storage  Stramonium shall be kept in well-closed containers, protected from light.

Identification
     A.  Shake 1 g of powdered drug with 10 mL of 0.05 M sulfuric acid for 2 minutes, filter, add 1 mL of strong ammonia solution and 5 mL of water to the filtrate, extract cautiously with 15 mL of peroxide-free ether to avoid the formation of an emulsion, dry the ether layer over anhydrous sodium sulfate, and filter.  Evaporate the ether in a porcelain dish, add 0.5 mL of nitric acid and evaporate to dryness on a water-bath.  Add 10 mL of acetone and, dropwise, a 3 per cent w/v solution of potassium hydroxide in ethanol:  a deep violet colour is produced.
     B.  Carry out the test as described in the “Thin-Layer Chromatography” (Appendix 3.1).
Standard solution  Dissolve 50 mg of hyoscyamine sulfate in 9 mL of methanol (solution A) and dissolve 15 mg of hyoscine hydrobromide in 10 mL of methanol (solution B); mix 3.8 mL of solution A with 4.2 mL of solution B and dilute to 10 mL with methanol.
Test solution  To 1.0 g of the powdered drug, add 10 mL of 0.05 M sulfuric acid, shake for 15 minutes, and filter.  Wash the filter with 0.05 M sulfuric acid until 25 mL of filtrate is obtained.  To the filtrate add 1 mL of strong ammonia solution and shake with two 10-mL portions of peroxide-free ether.  If necessary, separate by centrifugation.  Dry the combined ether layers over anhydrous sodium sulfate, filter, and evaporate to dryness on a water-bath.  Dissolve the residue in 0.5 mL of methanol.
Adsorbent  Silica gel G.
Mobile phase  Strong ammonia solution, water, acetone (3:7:90).
Application  Apply 10 µL and 20 µL each of Standard solution and Test solution as bands of 2 cm long and 0.3 cm wide, leaving 1 cm between the bands.
Development and drying  Allow the solvent front to ascend 10 cm above the line of application.  Dry the developed plate at 105° for 15 minutes; allow to cool.
Detection A  Spray the plate with acetic potassium iodobismuthate TS, using about 10 mL for a plate 20 cm square, until the orange or brown zones become visible against a yellow background.  Observe the result.  Examine the plate in daylight.
Results A  The test solution shows a band due to hyoscyamine in the lower third and a band due to hyoscine in the upper third of the chromatograms, corresponding in size, colour and R_f to the bands shown by the standard solution of the same volume applied.  Faint secondary bands may appear particularly in the middle of the chromatogram obtained from 20 µL of the test solution or near the point of application in the chromatogram obtained from 10 µL of the test solution.
Detection B  Spray the plate with sodium nitrite TS until transparent.  Observe the result after 15 minutes.  Examine the plate in daylight.
Results B   The bands due to hyoscyamine in the chromatogram obtained from the test solution change from brown to reddish brown but not to greyish blue (atropine), and any secondary bands disappear.

Foreign matter  Not more than 3.0 per cent w/w of stem with a diameter exceeding 5 mm (Appendix 7.2).

Acid-insoluble ash  Not more than 4.0 per cent w/w (Appendix 7.6).

Total ash  Not more than 20.0 per cent w/w (Appendix 7.7).

Assay  Reduce 50 g, selected from a well-mixed sample, to fine powder and determine the moisture content of 2 g by drying to constant weight at 105°.  Moisten 10 g, accurately weighed, with a mixture of 5 mL of 10 M ammonia, 10 mL of ethanol and 30 mL of peroxide-free ether and mix thoroughly.  Transfer the mixture to a small percolator with the aid of the extracting mixture if necessary, allow to macerate for 4 hours, and then percolate with a mixture of 1 volume of chloroform and 3 volumes of peroxide-free ether until complete extraction of the alkaloids is effected (Appendix 7.4).  Concentrate the percolate to about 50 mL by distillation on a water-bath and transfer to a separator with the aid of peroxide-free ether.  Add a quantity of peroxide-free ether at least 2.1 times the volume of the percolate to produce a liquid considerably less dense than water.  Extract the solution with not less than three 20-mL portions of 0.25 M sulfuric acid, separating the layers by centrifugation if necessary, and transfer each acid extract to a second separator. Make the combined extracts alkaline with 10 M ammonia and extract with three 30-mL portions of chloroform.  Combine the chloroform extracts, add 4 g of anhydrous sodium sulfate and allow to stand for 30 minutes, shaking occasionally.  Decant the chloroform and wash the sodium sulfate with three 10-mL portions of chloroform.  Evaporate the combined chloroform extracts and washings to dryness on a water-bath and heat the residue at 100° to 105° for 15 minutes.  Dissolve the residue in several mL of chloroform, add 20.0 mL of 0.01 M sulfuric acid VS, remove the chloroform by evaporation on a water-bath, and titrate the excess acid with 0.02 M sodium hydroxide VS using methyl red TS as indicator.  Each mL of 0.01 M sulfuric acid VS is equivalent to 5.788 mg of total alkaloids, calculated as hyoscyamine.