Myrrha, B.P. Myrrh.
Myrrh is a gum-resin obtained from the stem of Balsamodendron Myrrha, Nees. (N.O. Burseraceae), and probably other species, shrubs growing in North-Eastern Africa and Southern Arabia. It is also official in the U.S.P. When the stem is wounded a yellowish-white liquid exudes, which soon hardens to reddish-brown masses; these, collected in and exported from Somaliland, constitute the official drug. It occurs in irregular or rounded tears, or in masses of agglutinated tears. Externally it is reddish-brown, rough, and often covered with a fine dust. Fracture, brittle; the fractured surface granular, oily, and of a rich brown colour. Odour, agreeable and aromatic; taste, aromatic, bitter and acrid. Myrrh as imported is always mixed with other gums and gum resins, from which it is separated by picking. The oily granular surface, aromatic bitter taste and violet reaction with bromine sufficiently distinguish it, the admixtures being usually hard and uniform in fracture, sometimes vitreous, and with little taste, or with an acrid taste with the bitterness and aroma of myrrh. Bissabol (from B. Erythraeum, var. glabrescens, Engl.. is imported separately and has been mistaken for myrrh; it is readily distinguished by the different odour, by the smaller and yellower tears, and by the negative result of the B.P. bromine test. African bdellium is hard and has a dull, slaty fracture; Indian bdellium occurs in irregular, dark, reddish-brown masses, devoid of the characteristic odour and taste of myrrh; opaque bdellium occurs in opaque, yellow masses.
Constituents.—The chief constituents of myrrh are 25 to 40 per cent. of resin, 57 to 61 per cent. of gum, 2.5 to 8 per cent. of volatile oil, a bitter principle, and 3 to 4 per cent. of impurities. That portion of the resin which is soluble in ether contains three free resin acids, viz., α-, β-, and γ-commiphoric acids, the esters of a resin acid named commiphorinic acid, and two phenolic resins, α- and β-heerabomyrrhol. From the resin insoluble in ether, two other acids, α- and β-heerabomyrrhololic acids, have been obtained. These constituents show little analogy with the substances that have been isolated from other resins. The volatile oil is yellow, and rapidly resinifies when exposed to the air, producing resin similar to that contained in the myrrh itself; it contains free formic and acetic acids, and myrrholic acid (an isomer of γ-commiphoric acid) in the form of ester. Both volatile oil and resins yield the same characteristic violet reaction. The gum is apparently allied to gum acacia, and, like it, is associated with an oxydase. Good picked myrrh yields about 60 per cent. of substances insoluble in alcohol, and about 4 per cent. of ash. Commercial powdered myrrh is often of inferior quality, yielding as much as 13 per cent. of ash.
Action and Uses.—Myrrh is mildly disinfectant and is a local stimulant to the mucous membranes. Internally, like the other resins, it is carminative, and during excretion acts as a mild stimulating expectorant, diaphoretic and diuretic. It is used for mouth washes and gargles in ulcerated or relaxed throat and spongy gums. Myrrh is administered with aloes and iron in anaemia and amenorrhoea, as in Mistura Ferri Composita, Pilula Aloes et Myrrhae, and Pilula Aloes et Ferri; its emmenagogue action is more than doubtful. It is a common ingredient of tooth powders.
Dose.—3 to 6 decigrams (5 to 10 grains).
PREPARATIONS.
- Gargarisma Myrrhae, B.P.C.—MYRRH GARGLE.
- Tincture of myrrh, 5; clarified honey, 5; acid infusion of roses, to 100. Used as an astringent in aphthous stomatitis and ulcerated throat.
- Tinctura Myrrhae, B.P.—TINCTURE OF MYRRH.
- Myrrh, in coarse powder, 20; alcohol, sufficient to produce 100. Macerate the myrrh with 80 of alcohol for seven days, agitating frequently; then filter, and pass sufficient alcohol through the filter to make up to the required volume. Tincture of myrrh is used chiefly to make a mouth wash (1 in 30) for spongy gums and aphthous ulcerations. When added to lotions or mixtures in other than small quantities, the addition of mucilage of tragacanth is necessary to suspend the resin. Dose.—2 to 4 mils (½ to 1 fluid drachm).
- Tinctura Myrrhae, U.S.P.—Similar to B.P., but made with alcohol (95 per cent.).
- Tinctura Myrrhae Composita, B.P.C.—COMPOUND TINCTURE OF MYRRH. Syn.—Tinctura Myrrhae et Aloes; Horse Tincture of Myrrh.
- Myrrh, 5; Barbados aloes, 5; distilled water, 25; alcohol, 75. Used in veterinary practice, to promote the healing of wounds.
- Tinctura Myrrhae et Boracis, B.P.C.—TINCTURE OF MYRRH AND BORAX.
- Tincture of myrrh, 35; with tincture of krameria, oil of bergamot, oil of lemon, oil of orange, oil of neroli, oil of rosemary, borax, glycerin, and alcohol to 100. Used to make a mouth wash (1 in 20) for spongy gums and aphthous ulceration.
