Exudates, essential oils

Resin and Resinoid. Natural resins are plant exudates formed by the oxidation of terpenes. Many are acids or acid anhydrides. Prepared resins are made from oleoresins from which the essential oil has been removed. A resinoid is prepared by hydrocarbon extraction of a natural resin. 

The function of the essential oil in the plant is not fully understood. Microscopic examination of plant parts that contain the oil sacs readily shows their presence. The odors of flowers are said to act as attractants for insects involved in pollination and thus may aid in preservation and natural selection. Essential oils are almost always bacteriostats and often bacteriocides. Many components of essential oils are chemically active and thus could participate readily in metaboHc reactions. They are sources of plant metaboHc energy, although some chemists have referred to them as waste products of plant metaboHsm. Exudates, which contain essential oils, eg, balsams and resins, act as protective seals against disease or parasites, prevent loss of sap, and are formed readily when the tree tmnks are damaged. 

The aliphatic hydrocarbon heptane, CyHjg, has recently been discovered as a constituent of the oil obtained by the distillation of the resinous exudation of Pinus Sabiniana, Pinus Jeffreyi, and a few other essential oils. It is a highly volatile liquid of specific gravity 0 688 and boils at 98 to 99°. It has, probably, the lowest specific gravity of all liquids found naturally in essential oils. 

Herbal preparations are defined as preparations obtained by subjecting herbal substances to treatments such as extraction, distillation, expression, fractionation, purification, concentration or fermentation. These include comminuted or powdered herbal substances, tinctures, extracts, essential oils, expressed juices and processed exudates. 

Gum-res ins (Oleotesins), A group of aromatic exudations of plants which consist of a mixt of various substances (as essential oils) with the gum. The following are official (USP) ammoniac, assafeteda, gamboge, myrrh and scammony [Ref 3, p 392-L Ref 5, p 327-R (Oleoresins)]... 

Benzyl alcohol (1) occurs widely in essential oils both as the free alcohol, and, more importandy from a fragrance standpoint, in the form of various esters. Although benzyl alcohol itself is rather bland in odor, combined with its much more fragrant esters it is an important part of the odor of jasmine, ylang-ylang, gardenia, some rose varieties, narcissus and peony, as well as castoreum, balsams of peru and tolu, and propolis. Benzyl alcohol occurs primarily in flower oils and tree exudates, whereas a large number of essential oils obtained from other parts of a wide variety of plants contain no benzyl alcohol or its esters (1). 

There are a few minor wood-based chemical industries. After chestnut blight wiped out the American chestnut, U.S. tannin production essentially ceased. The main natural tannins, watde and quebracho, are now imported. High U.S. labor costs and the advent of synthetic tannins make re-establishment of a U.S. tannin industry unlikely. Tannins are used in oil-weU drilling muds. Tree exudates are a continuing wood-based chemical industry. Tree exudates include mbber, tme carbohydrate gums (eg, acacia gum), kinos (eg, the phenolic exudates from eucalyptus), balsams (eg, Storax from l iquidambar spp.), and many different types of oleoresins (mixtures of a soHd resin and a liquid essential oil). The most important oleoresin stiU collected in the United States is pine gum (rosin plus turpentine). 

Solvent extraction is generally applied in the separation of heat-labile plant materials or if an essential oil can be obtained only in very low yield (e.g., from blossoms). It is also used if the nonvolatile components are desired for their fixative properties (e.g., in the preparation of resinoids from exudates). 

Strictly speaking, resins are naturally occurring, nonpolymeric mixtures of carboxylic acids, essential oils, and terpenes that exude from various trees and shrubs and some insects that polymerize on exposure to atmospheric... 

Refers to any of a class of amorphous solids or semisolids. Natural resins occur as plant exudations (e.g., of pines and firs), and are also obtained from certain scale insects. They are typically yellow to brown in color, tasteless, and translucent or transparent. Oleoresins contain essential oils and are often sticky or plastic other resins are exceedingly hard, brittle, and resistant to most solvents. Resins are used in varnish, shellac, and lacquer and in medicine. Synthetic resins, e.g., bakelite, are widely used in making plastics. Refer to Varnish and Shellac. 

American turpentine n. Light-colored, volatile, essential oil obtained from resinous exudates or resinous wood associated with... 

Balsam bol-s3m [L balsamum, fr. Gk bal-samon, prob. of Semitic origin akin to Hebrew basham balsam] (before 12c) n. Oleoresinous exudations from plants, which are characterized by softness or a semi liquid consistency. They consist of mixtures of resin, essential oils, and other compounds. Typical balsams are Canada, gurjun, Peru, tolu, and storax balsams. Merriam-Webster s collegiate dictionary, 11th edn. Merriam-Webster Inc., Spring-field, MA, 2004. 

Canada balsam n. Oleoresin, which exudes naturally from Pinus balsameUy the Canadian balsam pine. It is essentially a resin dissolved in an essential oil. When freshly exuded it is a viscous liquid, but it hardens on exposure. Its chief use is for cementing lenses and other glass objects, because its refractive index, 1.53, is near that for glass. It is also used in the manufacture of fine lacquers. 

Essential oils are odorous principles stored in special plant cells— glands, glandular hairs, oil ducts or resin ducts—situated in any part of a plant or its exudations. These oils are responsible for the distinctive aromas associated with individual plant species. They are soluble in alcohol and fats, but only slightly soluble in water. Most essential oils are colourless, apart from azulene, which is blue. On exposure to light and air they readily oxidise and resinify. They are also called volatile oils, since they evaporate when subjected to heat. 

Schinus molle (family Anacardiaceae) Distributed in the tropics and subtropics of the Americas. The fruit is used in the preparation of mildly alcoholic drinks and the dried fruits are used like pepper. An essential oil can be extracted from the leaves and fruits the gum exuding from the trunk is chewed in Mexico. 

The most important natural sources of flavors are the essential oils derived from spices, fruits, and flowers as well as extractives and exudates (resins) from certain plant sources and animal secretions, e.g., musk. Essential oils are aromatic substances which are widely used in several industries such as perfume, pharmaceutical, food, and nutrition. These are mixtures of more than 200 compounds [14,16]. It contains monoterpenes, sesquiterpene hydrocarbons, and their oxygenated derivatives, along with aliphatic and aromatic aldehydes, alcohols, esters, and nonvolatile residues. Generally, terpenes are unsaturated com-... 

Markownikoff cyclization of 353 is represented by maaliol (360), a component of Maali resin, a soft exudate from Canarium samonense (275 vol. Illb). A related compound is maalioxide (361) from roots of Valeriana wallichii (305). Rearrangement of maaliane cation 355 (cf. Fig. 8.1.11), as shown in Fig.8.1.16, leads to the carbon skeleton of aristolene (362), which occurs in the essential oil from roots of Nardostachys jatamansi. (-i-)-Aristolene (a-ferulene) is present in the latex of Ferula communis (312). From roots of Aristolochia debilis, hydroxyketone 363 has been isolated (241). 

---