Part 1

U. S. DEPARTMENT OF AGRICULTURE.

BUREAU OF PLANT INDUSTRY--BULLETIN NO. 235.

B. T. GALLOWAY, _Chief of Bureau_.

WILD VOLATILE-OIL PLANTS AND THEIR ECONOMIC IMPORTANCE: I.--BLACK SAGE; II.--WILD SAGE; III.--SWAMP BAY.

BY

FRANK RABAK,

_Chemical Biologist, Drug-Plant, Poisonous-Plant, Physiological, and Fermentation Investigations._

+Issued January 30, 1912.+

WASHINGTON:

GOVERNMENT PRINTING OFFICE.

1912.

BUREAU OF PLANT INDUSTRY.

_Chief of Bureau_, +Beverly T. Galloway+.

_Assistant Chief of Bureau_, +William A. Taylor+.

_Editor_, +J. E. Rockwell+.

_Chief Clerk_, +James E. Jones+.

+Drug-Plant, Poisonous-Plant, Physiological, and Fermentation Investigations.+

SCIENTIFIC STAFF.

Rodney H. True, _Physiologist in Charge_.

A. B. Clawson, Heinrich Hasselbring, C. Dwight Marsh, and W. W. Stockberger, _Physiologists_.

James Thompson and Walter Van Fleet, _Experts_.

Carl L. Alsberg, H. H. Bartlett, Otis F. Black, H. H. Bunzel, Frank Rabak, and A. F. Sievers, _Chemical Biologists_.

W. W. Eggleston, _Assistant Botanist_.

S. C. Hood, G. F. Mitchell, and T. B. Young, _Scientific Assistants_.

Alice Henkel and Hadleigh Marsh, _Assistants_.

G. A. Russell, _Special Agent_.

LETTER OF TRANSMITTAL.

+U. S. Department of Agriculture+, +Bureau of Plant Industry+, +Office of the Chief+, _Washington, D. C., October 14, 1911_.

+Sir+: I have the honor to transmit herewith and to recommend for publication as Bulletin No. 235 of the series of this Bureau a manuscript prepared by Mr. Frank Rabak, Chemical Biologist, entitled “Wild Volatile-Oil Plants and Their Economic Importance: I.--Black Sage; II.--Wild Sage; III.--Swamp Bay,” submitted by Dr. R. H. True, Physiologist in Charge of the Office of Drug-Plant, Poisonous-Plant, Physiological, and Fermentation Investigations.

At present the various industries making use of volatile oils and their derivatives find their supply of these materials in products obtained from Old World plants grown in foreign lands. In some cases, because of the difficulty in producing these substances, it is likely that this commercial situation will persist for some time, but in other cases it seems likely that American resources may be capable of utilization. In our wild flora there are many oil-containing plants of considerable commercial promise and the purpose of this bulletin is to bring to notice the results of investigations which have been carried on with a number of these plants and to point out their commercial utility. It is presented as the first of a series, to be followed from time to time with the results of further investigations which are to be carried on with this class of plants and their products.

Respectfully, +B. T. Galloway+, _Chief of Bureau_. +Hon. James Wilson+, _Secretary of Agriculture_.

CONTENTS.

Page. Distribution of wild aromatic plants 7 Present production of volatile oils from wild plants native to the 7 United States Classification of volatile oils based on their odors and 8 constituents Commercial importance of volatile oils and their constituents 8 Plant sources of camphor, borneol, and cineol (eucalyptol) 10 Commercial uses of camphor, borneol, and cineol 13 Purpose of the investigation of wild aromatic plants native to the 14 United States Special investigations 14 Black sage 14 Botanical description and distribution 14 Distillation of the oil 14 Separation of stearoptene 15 Identification of camphor 15 Chemical examination of the oil 18 Chemical constants 18 Free acids 18 Combined acids 19 Fractionation of the oil 19 Identification and separation of the constituents 20 Pinene 20 Cineol, or eucalyptol 20 Camphor 20 Summary 21 Wild sage 21 Botanical description and distribution 21 Distillation of the oil 21 Separation of stearoptene 23 Identification of crystalline compound 23 Chemical examination of the oil 24 Chemical constants 24 Free acids 25 Combined acids 25 Fractionation of the volatile oil 26 Identification and separation of the constituents 27 Cineol 27 Fenchone 27 Borneol 28 Esters of borneol 28 Summary 28 Swamp bay 29 Botanical description and distribution 29 Distillation of the oil 30 Chemical examination of the oil 31 Chemical constants 31 Free acids 31 Combined acids 32 Soluble combined acids 32 Insoluble combined acids 32 Fractionation of the oil and separation of the stearoptene 32 Identification of the constituents of the oil 34 Camphor 34 Aldehyde constituent 34 Cineol, or eucalyptol 34 Borneol 35 Summary 35 Conclusions 36

ILLUSTRATIONS.

Page. +Fig.+ 1. A plant of black sage (_Ramona stachyoides_) growing near 15 Riverside, Cal. 2. Flowering top of a plant of black sage 16 3. A plant of wild sage (_Artemisia frigida_) 22 4. A field of wild sage near Webster, S. Dak. 23 5. A swamp bay tree (_Persea pubescens_) growing near Orange 29 City, Fla. 6. A small branch of swamp bay 30

TABLES.

Page.

+Table.+ I. _Comparison of properties of crystals from oil of black 17 sage and of pure camphor._

II. _Fractionation of the oil of black sage, showing the 20 physical properties of the fractions._

III. _Comparison of properties of crystals from oil of wild 24 sage and of pure borneol._

IV. _Fractionation of oil of wild sage, showing the 27 physical and chemical properties of the fractions._

V. _Fractionation of saponified oil of swamp bay and 33 description of fractions._

VI. _Refractionation of the oil of swamp bay, showing the 34 physical properties of the fractions._

[Sidenote: B. P. I.--707.]

WILD VOLATILE-OIL PLANTS AND THEIR ECONOMIC IMPORTANCE: I.--BLACK SAGE; II.--WILD SAGE; III.--SWAMP BAY.

DISTRIBUTION OF WILD AROMATIC PLANTS.

There exists in the flora of the United States a large number of plant families which include species of highly odorous character, many of which are known and described botanically as possessing peculiar aromas, but which have received no attention from the standpoint of their volatile-oil content. The various sections of the country, with their marked differences of soil and climate, possess floras peculiar to themselves which, if investigated, would doubtless reveal many plants valuable for their volatile oils. For example, in Florida and the South Atlantic States are found many plants with agreeable odors which thrive only in the climate and soil of that region. The Central Western States produce numerous species of sages and other plants found only in arid and semiarid climates. In the extreme Western States are numerous wild aromatic plants, some of which have been distilled and analyses made of the oils obtained therefrom.

PRESENT PRODUCTION OF VOLATILE OILS FROM WILD PLANTS NATIVE TO THE UNITED STATES.

Only a very few of the wild plants native to this country have been distilled and their volatile oils used for commercial purposes. Among these may be mentioned longleaf pine, sassafras, wintergreen, sweet birch, pennyroyal, horsemint, and Canada fleabane.

The first and by far the most important oil distilled from a wild plant indigenous to the United States was turpentine oil, which was distilled as early as the middle of the eighteenth century. The production of this oil is rapidly declining, owing principally to the employment of very wasteful methods, which have resulted in the destruction of many of the large pine forests. Turpentine is still obtained, however, from the longleaf pine (_Pinus palustris_), which occurs quite abundantly in the South Atlantic States from Virginia to Florida. The price of this valuable oil has risen so rapidly in recent years, owing to the shortage of raw material from which it is distilled, that a suitable substitute would be most desirable. This problem is now receiving the attention of scientific research workers, but no satisfactory substitute which can supply the trade has yet been found.

The commercial distillation of sassafras, wintergreen, and sweet birch possibly rank next in importance, although the oils are produced on a considerably smaller scale. These oils are used extensively by perfumers, confectioners, and manufacturers of toilet soaps. The plants are gathered in their native habitats and the quality of the oil depends upon the freedom from extraneous material, which can be insured only by extreme care in collection.

The production of pennyroyal and Canada fleabane oils from the wild plants is also carried on in a small way. The oils from these plants possess valuable therapeutic action and are used principally in medicinal preparations.

Horsemint and wild bergamot are wild aromatic plants which have been more recently distilled for their volatile oils. The use of these plants was brought about by the discovery that their oils contain, respectively, the valuable antiseptics thymol and carvacrol. The production of the oils, however, is not being carried on to any great extent.

These few species are practically the only wild aromatic plants of the United States which are at present being utilized for their volatile oils, and no attempt has yet been made to cultivate them in order to improve the quality or to increase the yield of the oils.

CLASSIFICATION OF VOLATILE OILS BASED ON THEIR ODORS AND CONSTITUENTS.

Volatile oils obtained from plants possess a great variety of odors, with no two exactly alike, although many are very closely related. A classification of these oils based on their odors is not satisfactory, since many which would not be considered as related if judged only by the sense of smell have chemical relationships, containing substances belonging to the same general class of chemical compounds. For our purpose volatile oils are divided into the following classes, basing the divisions upon odors and constituents. These groups comprise the majority of oils, but they are not arranged in the order of their importance:

(1) _Camphoraceous oils_, possessing a characteristic camphorlike odor, with camphor or camphor-related compounds predominating, as in the oils obtained from the camphor tree and from many of the sages. The products obtained from camphoraceous oils are extensively employed in the arts and in medicine.

(2) _Terebinthinate oils_, having a characteristic turpentinelike odor. These oils are obtained largely from the pine family, the turpentines of commerce being examples. They are composed largely of terpene hydrocarbons and find extensive application in the paint and varnish industries.

(3) _Sulphur-containing oils_, a small group characterized by extremely disagreeable and offensive odors, such as those of mustard, asafetida, garlic, and onion. These oils contain as their chief constituents sulphids, sulphocyanates, or nitriles, and are used principally for medicinal purposes.

(4) _Phenol and phenol-related oils_, containing phenols or phenol derivatives and characterized by strong, persistent odors, some very pungent and others pleasant. Owing to their phenolic constituents the density of these oils is usually very high. Common examples of this class are the oils of thyme, cloves, cinnamon, sassafras, anise, fennel, and the monardas. The usefulness of phenol and phenol-related oils depends largely upon their antiseptic properties, the principal constituents being thymol, carvacrol, eugenol, anethol, chavicol, safrol, and their derivatives.

(5) _Oils containing esters or alcohols_, by far the largest group, consisting of the fragrant oils which are used principally for perfumery purposes, although some find a use in medicine. The chief constituents of these oils are usually alcohols and esters, some few containing aldehydes, ketones, oxids, and lactones. Prominent here are the alcohols menthol, linalool, geraniol, citronellol, sabinol and their esters, benzyl alcohol and its esters, and anthranilic acid and its esters, forming the chief constituents of the oils of peppermint, lavender, geranium and rose, citronella, savine, ylang-ylang, and orange flowers, respectively. Other constituents are the aldehydes citral and citronellal from lemon and lemon-grass oils, and the ketones thujone, menthone, pulegone, carvone, and methyl heptenone from the oils of wormwood, peppermint, pennyroyal, caraway, and rue. The oxid cineol from eucalyptus and many other oils, and the lactone sedanolid from celery oil are further examples.

All volatile oils capable of being isolated from wild aromatic plants will fall into one or more of the foregoing divisions although, it must be understood, the classification is far from being satisfactory. It will, however, serve to elucidate the fact that although plant odors are of a very variable character they still possess some relationship.

COMMERCIAL IMPORTANCE OF VOLATILE OILS AND THEIR CONSTITUENTS.

Not only do volatile oils as such find important uses in commerce, but the great variety of constituents, one of which in many cases forms the major part of an oil, find equally important uses commercially.

Such constituents as have antiseptic properties occur widely in plant oils and are of untold value to the medical profession, to the manufacturer of pharmaceutical preparations, and to the maker of toilet lotions and dentifrices. Many volatile oils also contain constituents which are recognized as very important in the perfumery industries, their value depending not so much upon their own inherent odor as upon the effect which they produce in modifying or toning the fragrance of a mixture of several components. The finest perfumes are often mixtures of odors blended together and frequently contain oils which in themselves would not be regarded as very agreeable or pleasing in odor. In some instances a single constituent, as for instance citral, the chief constituent of lemon-grass oil, is used in its own pure condition without the admixture of other odors, as in the scenting of fine toilet soaps.

As flavoring agents considerable use is made of many of the volatile oils or of their constituents. For example, the oils of sassafras, peppermint, cinnamon, and wintergreen are used by confectioners in the flavoring of candies. The chief constituents of these oils (safrol, menthol, cinnamic aldehyde, and methyl salicylate) can, with the exception of menthol, be used with equal efficiency.

Many essential oils and the compounds isolated from them have proven highly useful in therapeutics, and enter into a number of medicinal preparations. Such constituents as menthol from peppermint oil, eugenol from clove oil, methyl salicylate from wintergreen and sweet-birch oils, thymol from thyme and horsemint oils, camphor from camphor oil, borneol from Borneo camphor oil, cineol from eucalyptus oil, and many others, comprise a group of medicaments which are indispensable.

From the foregoing account of volatile oils and their important constituents may be observed the possibilities which lie in this field of investigation. It is probable that a thoroughgoing examination of the wild flora of the United States would reveal the presence of volatile oils in many plants which at present are not known to yield volatile products. This possibility should stimulate the search for these products with a view to their commercial utilization.

PLANT SOURCES OF CAMPHOR, BORNEOL, AND CINEOL (EUCALYPTOL).

Owing to the presence in large quantities of the compounds camphor, borneol, and cineol in the oils to be described in this bulletin, the usual sources of these compounds are herewith presented, together with their commercial uses.

The occurrence of camphor in the vegetable kingdom as a component of volatile oils has been noted chiefly in such plant families as the Lauraceæ, Compositæ, Labiatæ, and Zinziberaceæ. The source of commercial camphor at present is the camphor tree, _Cinnamomum camphora_ (_Laurus camphora_), indigenous to Japan and Formosa. This tree has been introduced into the United States and experiments are now being conducted in Florida for the production of camphor, with some degree of success.

Two modifications of camphor occur in nature, the commercial variety, or dextrogyrate (rotating the plane of polarization to the right), and the levogyrate (having the opposite rotation). Comparatively few plants native to this country have been found to yield camphor. Whittelsey[1] has recently succeeded in isolating and identifying levo camphor in considerable quantities from the oil of a western sagebrush (_Artemisia cana_ Pursh., family Compositæ). Camphor has been observed in the native plant _Sassafras variifolium_ (_Sassafras officinalis_), a tree belonging to the family Lauraceæ. According to Power and Kleber,[2] sassafras oil contains from 6 to 8 per cent of dextro camphor. Traces of camphor have also been observed in tansy oil,[3] obtained from _Tanacetum vulgare_, a plant which is cultivated in the Eastern States for its volatile oil.

Borneol, or Borneo camphor, is closely related to camphor and possesses very similar properties. It is derived chiefly from the Borneo camphor tree (_Dryobalanops aromatica_ (_D. camphora_), family Dipterocarpaceæ), and is found in crude crystalline condition in the natural cavities of the wood.[4] _Blumea balsamifera_ (family Compositæ), a shrubby plant[5] native to India, also yields considerable quantities of borneol,[6] known to the natives as ngai camphor. The presence of borneol in plants native to this country is restricted to a few species, where it appears in the free condition only as a trace, being found more widely distributed as esters. It has been found in small quantities in the oil of red cedar (_Juniperus virginiana_),[7] and in thuja oil from the arborvitæ (_Thuja occidentalis_),[8] both trees being found abundantly in various sections of the United States. Small quantities have been found in the oils of other native plants, such as the goldenrod (_Solidago canadensis_),[9] Virginia snakeroot (_Aristolochia serpentaria_),[10] Texas snakeroot (_Aristolochia reticulata_),[11] Canada snakeroot (_Asarum canadense_),[12] tansy (_Tanacetum vulgare_),[13] and sweet gum (_Liquidambar styraciflua_).[14] As its acetic acid ester, it occurs in the oils of a large number of species of pines and firs.

Borneol and camphor occur occasionally together in the same oils. Their association is not surprising, since the relationship of the two compounds is very close. By oxidation borneol is readily converted into camphor. The two compounds have been observed together in the oil of cardamon,[15] distilled from the seeds of _Amomum cardamomum_; also in the oil of rosemary, from the plant _Rosmarinus officinalis_,[16] and in spike oil, obtained from _Lavandula spica_,[17] the latter two belonging to the mint family.

Cineol, or eucalyptol, is found chiefly in the volatile oils from various species of the eucalyptus tree and is the principal constituent of many of these oils. The blue gum tree (_Eucalyptus globulus_), belonging to the family Myrtaceæ and introduced abundantly in the western part of the United States, furnishes a volatile oil of which more than one-half is cineol. Other important sources also are cajuput oil[18] and niaouli oil[19] from _Melaleuca leucadendron_ (_M. viridiflora_), a plant indigenous to India. Only a few native aromatic plants are known to yield volatile oils which contain cineol and in only a very few cases has this constituent been found to be present in any quantity. It is known to occur in the oil of the California laurel, or mountain laurel (_Umbellularia californica_),[20] where it is present to the extent of about 20 per cent. Among other native plants in which cineol is known to occur in small quantities is the composite _Achillea millefolium_,[21] commonly known as milfoil or yarrow. Peppermint oil from _Mentha piperita_[22] and sage oil from _Salvia officinalis_[23] are said to contain small quantities of this constituent.

Camphor, borneol, and cineol are found in considerable quantities in volatile oils which have been distilled from three unutilized aromatic plants of the United States, which will be discussed fully in the subsequent pages of this bulletin.

COMMERCIAL USES OF CAMPHOR, BORNEOL, AND CINEOL.

As an article of commerce camphor is most useful, being employed extensively in the arts and in medicine. Its use in the arts is restricted principally to the manufacture of celluloid, a commodity which finds a great variety of uses. It also finds important uses in the manufacture of lacquers and pyrotechnics, in embalming, and, because of its odor, is used as an insectifuge. Camphor is also used to a great extent in medicine both for external and internal application, and enters into many pharmaceutical preparations.