Family: Araceae.

Oleum Calami. - Calmusol. - Essence de Calamus (acore).

Origin and Production. The root of Acorus Calamus, L. (family Araceae), which occurs well-nigh throughout Europe, Asia and North America, contains cells, both in the outer tissues of the bark and in the basal tissues of the interior part, which are filled with a volatile oil.

Upon steam distillation the fresh root which contains 70 to 75 p. c. of water, yields about 0,8 p. c, the unpeeled dry root about 1,5 to 3,5 p. c. of volatile oil. Calamus peels (the root bark) as well as the peeled root afford, when dried and distilled by themselves, smaller yields than the unpeeled dried root. This is due to the fact that the thin strips resulting from peeling lose more volatile oil because of volatilization and resinification than does the entire root. A calamus oil of inferior quality and deviating somewhat from the ordinary in its properties is distilled in Galicia.

1) Krafft, Berl. Berichte 12 (1879), 1667.

Composition. In the earlier days of chemical investigations, calamus oil was examined repeatedly but without much success1). A. Kurbatow2) established the presence of 5 p. c. of a terpene which boiled between 158 and 159° and yielded with dry hydrogen chloride a compound melting at 63°. It may be assumed that the terpene is pinene, although the hydrochloride of this melts at 125°.

The higher boiling portions of this oil have been examined by H. Thorns and R. Beckstroem3). The principal material used by them consisted of a fraction 272 to 340°: d20o1,0254; aD - 0,34°. When treated with a 2 p. c. soda solution, n-heptylic acid (m. p. of amide 96°), palmitic acid (m. p. 32°) and an unsaturated acid were isolated; when shaken with a 2 p.c. potassium hydroxide solution, eugenol (m. p. of benzoyleugenol 70,5 to 71°) was isolated.

The oil was then shaken with bisulphite solution, from which a liquid with a characteristic calamus-like odor was isolated. Upon standing there crystallized long needles of asarylic aldehyde (m. p. 114°; m. p. of oxime 137°) or 2,4,5-trimethoxybenz-aldehyde.

The free acids, phenols and aldehydes having been removed, the oil was saponified. In the saponification liquid palmitic and acetic acids were found. After fractionation of the oil a sub-stance C16H26o02 melting at 128° crystallized out. It is identical with the calamus camphor previously found by Schimmel & Co.1) and also by H. von Soden and W. Rojahn2), in calamus oil. Thorns and Beckstrcem designate this substance calameone.

1) T. Martius, Liebig's Annalen 4 (1832), 264 and 266. - Schnedermann, ibidem 41 (1842), 374. - ). H. Gladstone, Journ. chem. Soc. 17 (1864), Iff.; Jahrb. f. Chem. 1868, 546, 547. .

2) Berl. Berichte 6 (1873), 1210. - Liebig's Annalen 173 (1874), 4. The older references should be accepted with caution. Some of them, e. g. that of Gladstone (loc. cit), refer to adulterated oils.

3) Berl. Berichte 34 (1901), 1021; 35 (1902), 3187. - Berichte d. deutsch. pharm. Ges. 12 (1902), 257.

Calameone constitutes shiny crystals of the bisphenoid (rhombic-hemihedric) class of the rhombic system; [a]D26o - 8,94° in 5,04 p.c. alcoholic solution. When acted upon by bromine, calameone yields derivatives C16H21Br, C15H20Br2 and C15H18Br4. With hydrogen chloride it yields an addition product melting at 119°. Its benzoate melts at 155°. When heated with 50 p. c. sulphuric acid, calameone yields a hydrocarbon C15H22, calamene. When treated with bromine, this yields a compound C15H21Br; with hydrogen chloride a chlorhydrate melting at 108°; when oxidized with permanganate an acid melting at 196° in addition to acetic and oxalic acids.

When oxidized with potassium permanganate at ordinary temperature calameone is oxidized to calameonic acid, a mono-basic acid C15H2404 + H20 which contains a molecule of water of crystallization and melts at 153°. Heated to its melting point, it becomes anhydrous and then melts at 138°.

Inasmuch as calameone is neither an alcohol, aldehyde, ketone, acid, nor a phenol ether, its oxygen atom must be combined with two carbon atoms within a cycle. Hence its constitution is analogous to cineol.

From the mother-liquor of the crystals, Thorns and Beckstrcem obtained considerable amounts of a second, well crystallizable constituent which melted at 61° and revealed itself as asarone.

The constitution of calameone led to the supposition that, like cineol, it might combine with phosphoric or arsenic acids. This, however, proved not to be the case. When fraction 150 to 155° (10 mm.) was treated with a 90 p.c. arsenic acid, Thorns and Beckstroem obtained a white, plastic mass. This proved to be an arsenic compound which, when treated with water, yielded a substance melting at 173 to 184° and which, judging by elementary analysis and molecular weight determination, must be regarded as a polymer of asarone. By way of control, the same substance with like properties was obtained by the action of 90 p.c. arsenic acid on pure asarone. This compound, designated parasarone, is not oxidizable to asarylic aldehyde. Distilled in a vacuum, it is largely reconverted into asarone.

1) Report of Schimmel & Co. October 1899, 8. 2) Pharm. Ztg. 46 (1901), 243.

In addition to the substances enumerated, calamus oil contains two hydrocarbons C15H24. The one obtained from the middle fraction boils at 146° (19 mm.), has a sp.gr. d18o 0,9330 and is dextrogyrate, [a]D18o + 34,83°. The hydrocarbon from the higher fractions (b.p. 151° under 22 mm.; d12o 0,9336) is Isevo-gyrate, [a]d22° - 13,38°. Solid derivatives of these hydrocarbons have not been obtained thus far but only liquid chlorhydrogen addition products.

According to Kurbatow1), a sesquiterpene C15H24 (d14o0,932) is contained in fraction 250 to 255° which, after having been treated with sodium boils at 255 to 258° and does not combine with hydrogen chloride. At a still higher temperature a blue fraction distils over2).

Properties. Calamus oil is a somewhat viscid oil of yellowish to brownish-yellow color with a camphor-like, aromatic odor, and a corresponding bitter, burning, spicy taste. d15o 0,959 to 0,970; aD + 9 to +31°; nD20o5028 to 1,5078; A.V. up to 2,5; S.V. 6 to 20; E. V. after acetylation 32 to 50; methyl value (2 determinations)3) 15,3 to 16. In 90p.c. alcohol calamus oil is miscible in well-nigh all proportions. In dilute alcohol, however, it does not dissolve readily. Of 80 p.c. alcohol 15 vols, are required, of 50p.c. alcohol about 1000 vols, to produce a clear solution.

Japanese Calamus Oil. According to the investigations of Y. Asahina4) the Japanese calamus plant appears to be identical with the European Acorus Calamus, L. According to Holmes5), however, it is not impossible that the Japanese plant may be Acorus spurius, Schott, which occurs commonly in Japan and the rhizome of which differs but little from that of Acorus Calamus, L. The yield of oil amounts to as much as 5 p. c.

1) Loc. cit.

2) Fluckiger, Pharmakognosie. 1891, p. 352.

3) R. Beckstrcem, Berichte d. deutsch. pharm. Ges. 12 (1902), 266.

4) Apotheker Ztg. 21 (1906), 987.

6) Pharmaceutical Journ. III. 10 (1879), 102.

The properties of the Japanese oil are: d15o 0,973 to 0,992; aD + 7°20' to + 25°20'; soluble in 1 vol. of 90 p.c. alcohol, in 6 to 10 vols, of 80 p. c. and in about 500 vols, of 50 p. c. alcohol1). S.V. up to 3,9; E.V. after acetylation 17,0 (1 determination); methoxyl content 9,3 p.c. (1 determination)-).

According to Asahina2), the bulk of the oil distils over between 250 and 280°. A careful investigation revealed the absence of a terpene C10H16. The presence of methyleugenol was ascertained since the principal fraction yielded veratric acid upon oxidation. Inasmuch as the fraction was strongly optically active, and contained much more carbon than the formula of methyleugenol calls for, and since the oil assumed a green color upon the addition of acetic acid and sulphuric acid, Asahina infers the presence of a sesquiterpene.

Javanese Calamus Oil. A calamus oil distilled by Dr. Cart-haus in Java has been examined at the Botanical Institute at Buitenzorg3). It gave the following constants; d26o1,06; aD + 0°52'; S. V. 9.

Two similar oils from the same source have been described by Schimmel & Co.4). The constants of the one were: d15o1,0783; aD + 0°53'; nD20o1,55043; E.V. 12; those of the other d15o 1,0771 ; aD + 0°51'; nD20o 1,55065. From the common calamus oil these oils differ by their higher specific gravity, their lower rotation and their larger index of refraction. The Javanese oils were soluble in 1 to 1,5 vol. of 70 p.c. alcohol with the separation of small amounts of paraffin.