Wild volatile-oil plants and their economic importance

Chapter II: Part 2

Text size

As will be noted from the above, the chief constituents of the oil of wild sage are borneol camphor and cineol, each of which possesses valuable antiseptic qualities. Since there is a high percentage of these constituents, the oil from this wild plant should prove of value for medicinal purposes. Another important use of the oil is suggested by the high content of borneol, a constituent which finds application in celluloid manufacture, and which is readily separated from this oil. Lastly, combining the agreeable aromatic quality with its antiseptic qualities, the oil should prove important as an ingredient of medicinal soaps or as a scenting substance.

Inasmuch as the wild sage plant grows chiefly on sandy and stony hills which are practically waste lands and which require but little moisture, it would seem that the plant could be cultivated in various sections of the Northwestern States.

SWAMP BAY.

BOTANICAL DESCRIPTION AND DISTRIBUTION.

_Persea pubescens_ (Pursh.) Sarg., commonly known as swamp red bay or swamp bay (figs. 5 and 6), is an aromatic evergreen tree attaining a height of 30 feet or more, but usually occurring as a shrub. The leaves and twigs of the tree possess a pleasant camphoraceous odor. The swamp bay occurs abundantly in swamps and hammocks from North Carolina to Florida and Texas. The tree is a member of the family Lauraceæ, to which the camphor tree belongs.

DISTILLATION OF THE OIL.

Because of the strong camphoraceous odor and its close relationship to the camphor tree, the extraction and possible utilization of the oil from this wild aromatic plant suggested itself. Accordingly, during the summer of 1910, with the assistance of Mr. S. C. Hood, in charge of the station at Orange City, Fla., a small quantity of the leaves and twigs of this plant was distilled and a yield of about 0.2 per cent of oil was obtained. But with proper conditions and precautions the yield could no doubt be very materially increased, depending largely upon the time at which the distillation is made, and also upon the proportion of twigs and branches included. The above distillation was made late in the summer, long after the blossoming period, the stage at which a plant is usually most productive in volatile oils, and the material also contained many branches and much woody matter.

The oil obtained was pale yellowish brown in color, with a strongly aromatic and camphoraceous odor, and a persistent bitter, slightly pungent, and camphorlike taste. The specific gravity at 25° C. was 0.9272; specific rotation, A_{D} = +22.4°; refraction, N_{D} 25° = 1.4695. The oil was soluble in one-third its volume of 80 per cent alcohol, becoming faintly turbid upon the addition of five volumes or more of alcohol.

CHEMICAL EXAMINATION OF THE OIL.

CHEMICAL CONSTANTS.

A preliminary examination of the oil disclosed considerable free acidity, the acid number being 2.8, while the ester content was rather low, the ester number being 14.5. The low ester number would seem to indicate a low percentage of alcoholic compounds in combination with acids, and would correspond to 4.9 per cent of esters calculated as the acetate of borneol. After acetylization of the oil with acetic anhydrid the saponification number was found to be 64, which corresponds to 14.6 per cent of free alcohol, calculated as borneol.

In order to identify conclusively the constituents of the oil and the forms in which they occur, and to separate quantitatively the predominant constituents, the oil was subjected to a more careful and detailed analysis.

FREE ACIDS.

The free acidity of the oil as indicated by the preliminary tests was removed by shaking with 10 per cent aqueous sodium carbonate solution in several portions. The aqueous alkaline extracts, after being deprived of any adhering oil by extraction with ether, were concentrated, acidified, and distilled with a current of steam. The acids which were obtained separated principally as oily globules on the aqueous distillate, which was only faintly acid.

The free insoluble acids which were separated from the aqueous distillate by extraction with ether and evaporation of the solvent were neutralized with a solution of potassium hydroxid and then precipitated in fractions with a solution of silver nitrate.

Fraction 1. 0.0227 gram silver salt gave 0.0130 gram silver = 57.2
per cent silver.

Fraction 2. 0.0213 gram silver salt gave 0.0119 gram silver = 55.8
per cent silver.

It appears from the above results that the only acid existing in the free state in the oil is butyric acid, since silver butyrate gives theoretically 55.3 per cent of silver, fraction 1 being slightly contaminated, due possibly to a slight excess of potassium hydrate which was added when the acids were neutralized and which would appear in the first precipitate.

From the remaining faintly acid distillate, after neutralization with barium carbonate and concentrating, only a trace of precipitate, insufficient for silver determination, resulted upon the addition of silver nitrate solution. The butyric acid detected in the free insoluble acids was evidently extracted by the ether, in which it is very soluble.

COMBINED ACIDS.

As stated previously, the oil was found to contain a small percentage of esters, or organic acids in combination with higher alcohols. In order to identify these acids, which are in combination in the form of esters, a quantity of the oil, after removing the free acids, was saponified by heating on a water bath for half an hour with a slight excess of alcoholic potassium hydroxid. The mixture, after saponification, was diluted with water and the unsaponified oil separated. The alkaline liquid, which now contained the combined acids as their potassium salts, after being freed from adhering particles of oil by shaking with ether, was acidified with sulphuric acid and distilled with steam. The insoluble oily acids which formed on the distillate were separated by shaking the distillate lightly with ether and evaporating the ether.

SOLUBLE COMBINED ACIDS.

The aqueous portion of the distillate which contained the soluble combined acids of the oil was neutralized with barium carbonate, concentrated and precipitated with silver nitrate solution. Only a small precipitate resulted. This precipitate was found to contain 55.9 per cent of silver, which corresponds to silver butyrate. Hence the acid in the distillate was butyric acid.

INSOLUBLE COMBINED ACIDS.

As heretofore stated, the insoluble oily acids obtained by extraction with ether were carefully neutralized with potassium hydroxid solution and precipitated fractionally with silver nitrate. Two precipitates were obtained which were thoroughly washed and dried. The first and largest precipitate assayed 51.2 per cent silver, the second assaying 45.1 per cent silver. This would indicate that the insoluble acids were valerianic acid (silver valerianate requiring 51.6 per cent silver), and heptoic acid (silver heptoate requiring 45.5 per cent silver), the valerianic acid predominating.

The results show that the esters of this oil exist as the salts of butyric, valerianic, and heptoic acids, valerianic acid esters, however, predominating.

FRACTIONATION OF THE OIL AND SEPARATION OF THE STEAROPTENE.

For the purpose of accomplishing a separation of the constituents, 50 grams of the oil, after saponification, were dried and subjected to fractional distillation in a three-bulb Ladenburg flask. The results are given in Table V.

+Table V.+--_Fractionation of saponified oil of swamp bay and description of fractions._

Beginning with fraction 6 each successive fraction was refrigerated in a freezing mixture of ice and salt and the crystals separated by centrifuging in a platinum Gooch crucible. A total of 13.7 per cent of crystals was obtained.

In order to obtain a further separation of crystals the portions of the oil beginning with fraction 5 were fractionated into the following fractions: 190° to 195° C.; 195° to 200° C.; 200° to 205° C.; 205° to 215° C.; 215° to 233° C.; 233° to 260° C. A total of 4 per cent of crystals was obtained by refrigeration and centrifugation of those fractions in which crystals appeared. The portion between 190° and 215° C., and also fraction 4 of the original, were further fractionated into four parts: 185° to 190° C.; 190° to 195° C.; 195° to 205° C.; 205° to 215° C., an additional yield of 3.3 per cent of crystals being obtained.

By the above method of successive fractionation and refrigeration a total of 21 per cent of crystals was obtained from the oil. This represents only approximately the total percentage of stearoptene in the oil. The separation was not at all quantitative, as a considerable proportion was lost in the manipulations incident to the separation. Since the quantity of oil at hand was so meager the fractions were reduced to such small quantities that further separation of crystals was impossible, and as unavoidable losses were encountered in transferring to and from the centrifuge the final percentages were materially affected and the true amount of stearoptene may be assumed to be considerably more than is shown above.

After the fractionation and refractionation of the oil and the separation of the stearoptene portion, the remaining elaoptene portion grouped itself into fractions, whose physical properties were determined and qualitative tests for their constituents applied, as shown in Table VI.

+Table VI.+--_Refractionation of the oil of swamp bay, showing the physical properties of the fractions._

---------+------------+-------------+-------------+-----------+----------------
| | Specific | Rotation |Re-fraction|
Fraction.|Temperature.| gravity | in 50 mm. | N_{D} | Tests applied.
| | at 25° C. | tube. | 25°. |
---------+------------+-------------+-------------+-----------+----------------
|_Degrees C._| | _Degrees._ | |
1 |Below 170 |Insufficient.|Insufficient.| 1.4648 | When shaken
| | | | |with water the
| | | | |aqueous solution
| | | | |strongly reduced
| | | | |magenta solution
| | | | |to violet color;
| | | | |also produced
| | | | |silver mirror
| | | | |with ammoniacal
| | | | |silver nitrate.
2 |170 to 182 | 0.9011 | +22.5 | 1.4630 | Iodol
| | | | |(tetraiodopyrol)
| | | | |dissolved in oil
| | | | |by gentle
| | | | |warming yielded
| | | | |yellow crystals
| | | | |melting at
| | | | |115° C.; cineol
| | | | |iodol melts at
| | | | |112° C.
3 |182 to 185 | .9012 | +21.5 | 1.4628 | Treated with
| | | | |iodol and the
| | | | |yellow crystals
| | | | |recrystallized
| | | | |from benzol
| | | | |melted sharply
| | | | |at 112°.
4 |185 to 190 | .9075 | +23 | 1.4628 | Cineol-iodol
| | | | |crystals melted
| | | | |at 113° C.
5 |190 to 205 | .9228 | +31 | 1.4653 | Do.
6 |205 to 215 | .9351 |.............| 1.4706 | Negative test
| | | | |with iodol.
7 |215 to 233 | .9358 |.............| 1.4765 | Do.
8 |233 to 260 | .9360 |.............| 1.4830 | Oxidized with
| | | | |3 per cent
| | | | |potassium
| | | | |permanganate
| | | | |in cold yielded
| | | | |camphor
| | | | |crystals.
---------+------------+-------------+-------------+-----------+----------------

IDENTIFICATION OF THE CONSTITUENTS OF THE OIL.

_Camphor._--The compound obtained from the oil by refrigeration was a soft, white, granular, crystalline mass, and possessed a distinct camphorlike odor and slightly bitter camphoraceous taste. The crystals sublimed readily and melted at 174° to 176° C. The boiling point of the compound was 205° C., and the rotation in a 50 mm. tube of 20 per cent solution in alcohol was found to be +3.8°, 20 percent solution of commercial camphor in alcohol rotating +3.5°. It was readily soluble in alcohol and the other organic solvents.

To further identify the crystals with ordinary camphor two compounds were prepared, the semicarbazone and the oxime, with which camphor forms definite chemical compounds. The semicarbazone was prepared according to the method of Tiemann. (See p. 17.) The crystals obtained after recrystallization from alcohol melted at 237° to 239° C., pure camphor semicarbazone melting at 236° to 238°. For the preparation of the oxime Auwers’ method was applied. (See p. 16.) Recrystallized from ether the oxime melted at 117° to 118° C., whereas pure camphor oxime melts at 118° to 119° C.

Since the physical and chemical properties of this substance correspond almost identically with those of camphor, it may be safely stated that the crystals are those of commercial dextro camphor.

_Aldehyde constituent._--From the pungent and penetrating odor and the strong reducing properties of the first fraction, which, as shown in Table V, distilled largely below 80° C., there would seem to be the possible presence of a trace of formaldehyde.

_Cineol, or eucalyptol._--Qualitative tests as indicated in Table V show the presence of cineol in fractions from 170° to 205° C., the characteristic crystalline cineol addition product of iodol corresponding in melting point to the pure cineol iodol. Cineol was further identified in these fractions by the preparation of cineol hydrobromid prepared by passing dry hydrobromic acid gas into a well-cooled solution of the oil in petroleum ether. A crystalline hydrobromid was obtained from each fraction which gave the iodol reaction. The hydrobromids prepared melted between 55° to 57° C., while pure cineol hydrobromid is reported as melting at 56° to 57° C.

Since the presence of cineol in the several fractions of the oil was proved, a quantitative estimation was deemed desirable. Because of the smallness of the individual fractions the hydrobromic acid method was adopted in this estimation, it being the most accurate when cineol is present in only small quantities. The phosphoric acid method is best adapted to oils which are very rich in the compound. The hydrobromic acid method has been used in the assay of eucalyptus oils,[35] and consists essentially in conducting dry hydrobromic acid gas into a solution of the oil in about twice its volume of petroleum ether, the solution being well cooled by a freezing mixture, separating the crystals on a force filter, washing and decomposing with water, and measuring the cineol formed. A slight deviation was made from the directions on account of the smallness of the fractions and consequently the small amount of hydrobromid obtained, which when decomposed with water would introduce an error. After the hydrobromid of cineol was obtained in each case and washed it was weighed and the percentage of cineol was calculated from the weight of the crystals from a given quantity of each fraction. In this manner by assaying the four fractions which gave qualitative tests there was found to be a total of 19.8 per cent of cineol in the oil.

_Borneol._--By oxidation of fraction 233° to 260° C. with a 3 per cent solution of potassium permanganate, slightly warming and allowing it to stand for 12 hours, then shaking out the mixture with ether and allowing the ether to evaporate, a mass of crystals remained which proved to be camphor. It is possible that borneol was present in this fraction, as borneol is readily oxidized to camphor with ordinary oxidizing agents. Since the preliminary chemical examination of the oil indicated a small percentage of esters and of free alcohol, the alcohol was probably borneol.

SUMMARY.

From the results obtained in the chemical examination it appears that the oil of swamp bay contains over 21 per cent of camphor, 19.8 per cent cineol, and borneol, the latter possibly occurring to a small extent as esters and as the free alcohol. No terpenes were identified. Since only a very small portion of the oil distills over below 175° C., it would seem that the oil is not terpenic in character, as most members of the terpene group of hydrocarbons boil below 175° C.

Besides the constituents mentioned, the oil contains butyric acid in free condition to a slight extent; butyric, valerianic, and heptoic acids combined in the oil as esters, valerianic acid predominating, and a slight trace of an aldehyde, possibly formaldehyde.

This oil possessing, as has been proved, considerable quantities of such constituents as camphor, cineol, and borneol, all of which are valuable therapeutic agents, may be of economic importance from the standpoint of the perfumer or the medical practitioner. Doubtless if the distillation of the plant were carried on, attention being paid to the stage of growth at which it is distilled and the distillation restricted to the leaves and small twigs, the yield of oil and possibly the yield of the three important constituents mentioned could be considerably augmented.

CONCLUSIONS.

The plants described in the foregoing pages and the volatile oils distilled from them represent but a small part of our wild aromatic flora, yet these plants gathered from their wild haunts have been made to yield products which give promise of no little economic importance. It is the object of this work simply to call attention to the products capable of being obtained from our native plants and to emphasize their possible application in the trades and arts. The actual growth and cultivation of such as prove to be of economic value should follow.

The lands on which the rankest growth of wild plants occurs are usually of little value for the production of agricultural crops, and doubtless large areas of this character exist in all sections of the United States, which lands might be utilized for the growth of certain aromatic plants now largely classed as weeds yet which may be made to yield products of value.

That there is a field for investigation in this direction is shown in the preceding pages in which three plants representing specimens picked up at random have been shown to yield oils containing large quantities of such important compounds as camphor, borneol, and cineol. Inasmuch as camphor is consumed in enormous quantities in the United States, the supply at present coming wholly from foreign countries, the presence of such large quantities of this substance in the volatile oils of black sage and swamp bay should not be overlooked. The cultivation of these plants should not be impracticable. Since black sage if distilled at its flowering stage could be made to yield approximately 1 per cent of oil from the green plant and the oil in turn be made to yield from 40 to 50 per cent of camphor, its growth and cultivation should be profitable. Furthermore, as the plant is a perennial, a crop of foliage could be produced each year, and the luxuriant growth of the plant, coupled with the exceptionally high yield of oil would produce a large amount of oil and camphor per unit of area. After the separation of the camphor from the oil the camphor-free oil remaining would still possess value because of its high content of cineol.

The swamp bay, which yields oil and camphor, though in somewhat smaller quantities, should also receive attention along similar lines.

The wild sage is an example among the wild plants of the United States in which borneol is found in quantity. As a natural source for this compound the plant is far more promising than the two plants native to Borneo and the Malay Archipelago, which yield most of the borneol of commerce, supplying a large proportion to the Chinese, among whom there is a brisk demand. The abundance of wild sage found in this country, the ease with which it might be cultivated, and the large percentage of borneol and cineol capable of separation from the oil make it a most excellent source from which to obtain these substances. The oil also possesses virtues as a scenting agent because of the high percentage of the esters of borneol, which are excellent perfuming materials. As a source for the production of bornyl acetate which is extensively used by perfumers for its pine-needle odor, this oil should prove of value.

Since the oil from each of these plants shows important chemical constituents which may be commercially applied in many ways, their cultivation for these products is worthy of consideration.

FOOTNOTES:

[1] Whittelsey, Th. A New Occurrence of l-Camphor. Otto Wallach Festschrift. Göttingen, 1909, pp. 668-670.

[2] Power, F. B., and Kleber, C. On the Chemical Composition of the Oil of Sassafras Bark and Oil of Sassafras Leaves. Pharmaceutical Review, vol. 14, 1896, pp. 101-104.

[3] Schimmel & Co., Semiannual Report, October, 1895, p. 47.

[4] Kremers, E. Borneo Camphor. Pharmaceutical Review, vol. 23, 1905, pp. 7-14.

[5] The earlier name for this genus is Placus (Loureiro, 1790), the name Blumea being published by De Candolle in 1833.

[6] Schimmel & Co., Semiannual Report, April, 1895, p. 76.

[7] Ibid., 1898, p. 14.

[8] Wallach, O. Untersuchungen aus dem Universitätslaboratorium zu Göttingen, XIV. 4. Ueber das Semicarbazon des d- and l-Fenchons und das Vorkommen von l-Borneolester im Thujaöl. Nachrichten der Königlichen Gesellschaft der Wissenschaften zu Göttingen, vol. 1, 1905, p. 11.

[9] Schimmel & Co., Semiannual Report, April, 1897, p. 46.

[10] Spica, M. Studio Chimico dell’ Aristolochia Serpentaria: Nota Preliminare. Gazzetta Chimica Italiana, vol. 17, 1887, pp. 313-316.

[11] Peacock, J. C. Volatile Oil of Aristolochia Reticulata, Nuttall. American Journal of Pharmacy, vol. 63, 1891, pp. 257-264.

[12] Power, F. B., and Lees, F. H. The Constituents of the Essential Oil of Asarum Canadense. Journal of the Chemical Society, London, vol. 81, 1902, pt. 11, pp. 59-73.

[13] Schimmel & Co., Semiannual Report, October, 1895, pp. 46-47.

[14] Ibid., April, 1898, p. 53.

[15] Ibid., October, 1897, p. 12.

[16] Gildemeister, E., and Stephan, K. Beiträge zur Kenntniss der ätherischen Oele, VI. Archiv der Pharmazie, vol. 235, 1897, p. 585.

[17] Bouchardat, G. Sur l’Essence d’Aspic (Lavandula Spica). Comptes Rendus, Academie des Sciences, vol. 117, 1893, pp. 53-56.

[18] Wallach, O. Über die Bestandtheile einiger ätherische Oele. Justus Liebig’s Annalen der Chemie, vol. 225, 1884, pp. 314-318.

[19] Bertrand, G. Sur la Composition Chimique de l’Essence de Niaouli. Comptes Rendus, Société des Sciences, Paris, vol. 116, 1893, pp. 1070-1073.

[20] Power, F. B., and Lees, F. H. The Constituents of the Essential Oil of California Laurel. Journal of the Chemical Society, London, vol. 85, 1904, pt. 1, pp. 629-639.

[21] Schimmel & Co., Semiannual Report, October, 1894, p. 38.

[22] Power, F. B., and Kleber, C. The Constituents of American Peppermint Oil, and a Method for the Quantitative Determination of Menthol. Pharmaceutische Rundschau, vol. 12, 1894, pp. 157-165.

[23] Wallach, O. Zur Kenntniss der Terpene und der ätherischen Oele. Justus Liebig’s Annalen der Chemie, vol. 252, 1889, pp. 94-157.

[24] Janse, J. M. Le Dryobalanops Aromatica Gaertn. et le Camphre de Borneo. Annales du Jardin Botanique de Buitenzorg, supplement 3, pt. 2, 1910, pp. 947-961.

[25] Auwers, K. Zur Darstellung der Oxime. Berichte der Deutschen Chemischen Gesellschaft, vol. 22, 1889, pp. 604-607.

[26] Michaelis, A., and Erdmann, G. Ueber die Thionylamine der Amidoazoverbindungen und der Naphtylendiamine. Berichte der Deutschen Chemischen Gesellschaft, vol. 28, 1895, pt. 2, pp. 2192-2204.

[27] Wallach, O. Zur Kenntniss der Terpene. Justus Liebig’s Annalen der Chemie, vol. 245, 1888, p. 251.

[28] Pharmacopœia of the United States, 8th decennial revision, 1900, p. 313.

[29] Rabak, Frank. On Several New Artemisia oils. Pharmaceutical Review, vol. 23, 1905, pp. 128-129.

[30] Ibid., vol. 24, 1906, pp. 324-325.

[31] This fraction distilled largely between 170° and 175° C.

[32] Wallach, O. Zur Kenntniss der Terpene und der ätherischen Oele. Justus Liebig’s Annalen der Chemie, vol. 272, 1892, p. 102.

[33] Ibid., p. 104.

[34] To prevent clogging of the condenser with crystals, the jacket of the condenser was deprived of the cold water, and steam passed through, the melted crystals passing over. The crystals immediately reappeared in the fractions upon cooling.

[35] Gildemeister, Eduard, and Hoffmann, Friedrich. Translated by Edward Kremers. The Volatile Oils, p. 528.

Transcriber’s Notes

Possible printer’s errors and inconsistencies, including spelling, hyphenation, punctuation, and spacing, were retained except for changes listed below.

_Italics_ and +Small Caps+ have been converted as so.

Subscripts, such as H_{2}O, were converted as so.

Illustrations have been moved to better fit the text and for standardization, but the page numbers on the list of illustrations have been left unchanged. Likewise, other page number errors in the TOC were retained.

A Table of Tables has been added for ease of use.

Footnotes were reindexed and moved to the end of the book.

Where there was no, or debatable, space between a number and either a scientific variable or abbreviation, a space was added or assumed.

On page 7, a heading was included as a sidenote.

On page 11, a missing closing bracket was added to “Aristolochia serpentaria”.

On page 14, a missing period was added to the sentence that ends with “green and wrinkled above and ash colored and hairy below”.

On page 27, a missing period was added to the “C” as in “Celsius” that follows “Fraction 1”.

On page 27, the footnote connected to the word “Wallach” was missing its number in the footnote, so a number was added for consistency.

On page 33, a missing “to” was added to “200° to 205°”.

In table VI, “50-mm. tube” was standardized to “50 mm. tube” for consistency with the text elsewhere.

In table VI, the formatting of the numbers in the “Fraction” column were changed from right-justification to left-justification to match the other tables.

In table VI, the formatting of the numbers in the “Rotation” column were changed to match the respective column of other tables.

On page 34, “Auwer’s” was changed to “Auwers’” since the name of the person is “Auwers”.

Comments

Wild volatile-oil plants and their economic importanceChapter II: Part 2

0%18 min left in chapter