Arnica Montana

DESCRIPTION

All parts of the plant have a pleasantly aromatic odour.

The rhizomes are up to 10cm long and lcm thick, yellowy or pale grey, often curved, sometimes branching or with multiple heads, with small knots, annulation, and with blackish brown remnants of scale leaves on the thickened axes. They bear numerous elongated roots that are up to 3mm thick and only have thin adventitous roots in their lower parts. In transverse section the rhizome has a narrow cortex and a central cylinder occupying about two thirds of the diameter with a yellowy stellate woody part and soft light-coloured medulla. The roots have a wide cortical zone, with the central cylinder occupying not more than half the diameter.

The leaves forming a rosette at the base are elongated, obovate and narrow down to a leaf base that in part is narrow and drawn out to appear like a petiole. They are up to 10cm long and up to 4cm wide, with margins entire; slightly wavy in the margin, with the apex obtuse or acute. The main vein is clearly marked and projects on the underside, 2-4 delicate veins run lengthwise through the leaf. The leaves are more or less covered with shaggy glandular trichomes and the margins are ciliate.

The round, hollow stem is 20-60cm high, simple or with a few branches, the upper part in particular bears glandular hairs. The stem bears 1 or 2 pairs of opposite or distantly paired leaves that are smaller than the leaves in the rosette.

The stem usually bears one capitulum; only rarely do a few more grow from the axils of the upper leaves on the stem. The capitula are 6-8cm wide and golden to orange yellow. Each is invested with a bell-shaped involucre of 20-40 narrow lanceolate bracts arranged in 2 rows; these are 1.5cm long, pointed with short shaggy hairs, green, sometimes with a red tinge. The disc is 0.6-1cm wide, slightly convex and invested with short, stiff white hairs. The 14-20 yellow ligulate ray florets are 15-25mm long, usually all female, their corollas are tubular at the base and hairy on the outside and terminate in a 3-toothed ligute that is more or less and irregularly reflexed. Pistil, ovary and pappus are like those of the tubular florets. The 50 or more tubular ray florets open from periphery to centre; they are hermaphrodite and up to 1.5cm long; the lower part of the corolla is pale yellow, bulbous tubular and hairy on the outside; it widens half way up and terminates in an orange yellow seam that has five divisions, each with 3 teeth that are more or less reflexed. The stamens are 5-6mm long, the cuticulae on the anthers fused to a tube, with the free filaments inserted at about the centre of the corollary tube. The connectives are drawn out into a short triangular lappet at the tip. The branches of the filiform pistil are initially close together and later reflexed apart. The brownish ovary narrows slightly at the base, is 4-6cm long, elliptical or faintly quadrangular or pentagonal, glabrous at the base and elsewhere, particularly at the top densely hairy with trichomes pointing upwards. At the tip is a uniseriate pappus of yellowy white very friable bristles; this is 8mm long, which is about the same length as the corolla.

PREPARATIONS

MANUFACTURE

The mother tincture and liquid dilutions by Method 3c.(*)

CHARACTERISTICS

The mother tincture is a yellow lid with characteristic odour and bitter taste.

IDENTIFICATION

A. Dilute 0.5ml of the mother tincture with 5ml of water. The solution is opalescent and turns yellow on addition of 0.1ml of dilute sodium hydroxide solution R.

B. Dilute 1ml of the mother tincture with 1ml of ethanol 30 per cent and add 0.2ml of. iron (III) chloride solution R1. A yellowy green colour is produced.

C. Chromatography. Use thin-layer chromatography on a layer of silica gel HR.

Test solution: Remove the ethanol from 25ml of the mother tincture on a water bath. Dilute the residue to 10ml with water and transfer the solution to a small separating funnel. Add 20ml of ethyl acetate R and extract for 2 minutes. Add 0.5g of powdered tragacanth RN to the organic phase, filter and evaporate. Dissolve the residue in 1ml of ethyl acetate R.

Control solution: Dissolve 10mg of caffeic acid R and 10mg of rutin R in 10ml of methanol R.

Apply separately 20 ul of the test solution and 10 ul of the control solution. The mobile phase is a mixture of 50 parts by volume of chloroform R, 42 parts by volume of acetic acid 98 per cent R and 8 parts by volume of water. Allow the solvent front to rise 15cm above the line of application. Following complete evaporation of the mobile phase, spray first with a 1 per cent solution (w/v) of diphenylboryloxyethylamine R in methanol R, and then with a 5 per cent solution (w/v) of polyethylene glycol 400 R. Evalute under ultra-violet light (365nm).

The chromatogram for the control solution has the orange spot of the rutin standard in the lower and the greeny blue spot of the caffeic acid standard in the middle part.

The chromatogram of the test solution has one to three greeny blue spots, a blue spot and an orange one in ascending order in the range covered by the two standards. Immediately above the caffeic acid standard is a greeny blue spot. Two or three further greeny blue spots appear in the upper part of the chromatogram.

ASSAY FOR PURITY

Relative density (Eur. P.): 0.955-0.969.

Dry residue (German P.): Not less than 1.0 per cent.

STORAGE

Protected from light.

(*)METHOD 3c:

Mother tinctures and liquid dilutions.

Mother tinctures for Method 3c are produced using ethanol 43 per cent (ethanol content approx. 30 per cent).

The plant is cut up finely. A sample is used to determine loss on drying. To the cut-up plant material add immediately at least half the amount by weight of ethanol 43 per cent and store in well sealed containers at a temperature not exceeding 20øC. Calculate the amount of ethanol 43 per cent required, deduct the amount of ethanol that has already been used, and add the final amount to the mixture.

{equation}

where E = weight of ethanol in kg

M = weight of plant material in kg

D = loss on drying in sample in per cent

Use ethanol 30 per cent to adjust to any concentration required in the Monograph.

British Homoeopathic Association (BHA).

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