Natural chemical constituents

Wintergreen Oil. Water distillation of the leaves of Gaultheriaprocumbens L. yields an oil which consists of essentially one chemical constituent, methyl saUcylate. Because of this, the oil has been almost totally replaced by the synthetic chemical. Natural oil of wintergreen [68917-75-9] is a pale yellow to pinkish colored mobile Hquid of intensely sweet-aromatic odor and flavor. The oil or its synthetic replacement find extensive use in pharmaceutical preparations, candy, toothpaste, industrial products, and in rootbeer flavor. In perfumery, it is used in fougnre or forest-type fragrances. 

There are a number of nitro-compounds known under the name of artificial musk, all of which may conveniently be grouped together here. The natural odorous constituents of musk appear to be, in the main, ketonic compounds free from nitrogen, so that the term artificial musk must be understood to mean artificially prepared bodies, having musklike odours, but not having any direct chemical relationship with natural musk perfume. 

The material in this section is divided into three parts. The first subsection deals with the general characteristics of chemical substances. The second subsection is concerned with the chemistry of petroleum it contains a brief review of the nature, composition, and chemical constituents of crude oil and natural gases. The final subsection touches upon selected topics in physical chemistry, including ideal gas behavior, the phase rule and its applications, physical properties of pure substances, ideal solution behavior in binary and multicomponent systems, standard heats of reaction, and combustion of fuels. Examples are provided to illustrate fundamental ideas and principles. Nevertheless, the reader is urged to refer to the recommended bibliography [47-52] or other standard textbooks to obtain a clearer understanding of the subject material. Topics not covered here owing to limitations of space may be readily found in appropriate technical literature. 

The isolation and structural characterization of plant constituents are often difficult and time-consuming. Consequently, at the present time, only a small percentage of the total number of natural plant products has been identified. Early in the development of natural product chemistry it was apparent to many botanists and chemists that plants might be characterized and classified on the basis of their chemical constituents. The distribution of chemical constituents among plant families is presented by Swain (139) and Hegnauer (66). 

From now on, we adopt a notation that reflects the chemical nature of the data, rather than the statistical nature. Let us assume one attempts to analyze a solution containing p components using UV-VIS transmission spectroscopy. There are n calibration samples ( standards ), hence n spectra. The spectra are recorded at q wavelengths ( sensors ), digitized and collected in an nx.q matrix S. The information on the known concentrations of the chemical constituents in the calibration set is stored in an nxp matrix C. Each column of C contains the concentrations of one of the p analytes, each row the concentrations of the analytes for a particular calibration standard. 

If amylases are to be used as tools for the detailed study of the breakdown and structure of their substrates it is obviously important to separate them from other enzymes and from other naturally associated constituents which may influence the results. It is then equally important to study the properties of the purified amylase and to supply it with the chemical environment necessary to protect it from inactivation and to enable it to act efficiently. With beta amylases this ideal has often been approached. Beta amylases from several sources have been prepared by selective inactivation of other enzymes that accompany them in nature23 and highly active products have been obtained by extensive purification.20 24-26 Balls and his associates have recently reported the crystallization of beta amylase from sweet potato.27... 

Before delving into ways the living world uses its special chemicals, we should note that these compounds touch our own lives in important ways. For millennia, humans have been borrowing natural chemicals for their own purposes, most often as drugs. Our oldest medicine is opium, which we prepare from the opium poppy (Papaver somniferum) today much as Mediterranean peoples did four thousand years ago. Just as we do, these early communities valued opium for its ability to kill pain and impart a sense of well-being. The principal constituent responsible for these effects is a chemical compound called morphine, which remains unsurpassed in its ability to control severe pain. In poppies, morphine s toxicity and bitterness presumably repel herbivores looking for a tasty meal. 

Since botanicals are natural products (usually extracts), variations in the composition of the chemical constituents due to seasonal variations, crop location, time of harvest, etc. are commonly encountered. 

Timber can be viewed as a classic renewable material. Trees absorb carbon dioxide and utilize water and sunlight to produce a material that can be used in construction, to produce paper or to provide chemical feedstocks, with the production of oxygen as a byproduct. Furthermore, at the end of a product life cycle, the material constituents can be combusted, or composted to return the chemical constituents to the grand cycles . In essence, timber use represents a classic example of a cyclic materials flow, mimicking the flows of materials through natural cycles. Provided that we manage our forests well and do not harvest beyond the capacity of the planet to provide timber, we have at our disposal an inexhaustible resource available in perpetuity. 

Conversely, active constituents may have cooperative effects and together act in an additive or synergistic (supra-additive) manner. In such cases, it would be better to consume the whole plant or extract, because the combination of constituents would give a greater effect than one alone. Thus, to blindly advocate either the use of whole herb or refined single constituents is naive. To fully know what is best for the desired effect, herbs must be considered on a case-by-case basis and the nature of the interactions between the chemical constituents must be carefully considered. Not only must we understand what the plant s chemical constituents do, we must also investigate how they interact. The Use of Herbal Medicine The Current Prevalence of Alternative Medicine... 

ElSohly MA, Slade D, Chemical constituents ofmarijuana The complex mixture of natural cannabinoids. Life Sci 78 539—548, 2005. 

Ito, C. et al., Chemical constituents of Millettia taiwaniana structure elucidation of five new isoflavonoids and their cancer chemopreventive activity. Journal of Natural Products, 67, 1125, 2004. 

When the reactivity of a solid is controlled by the crystal structure, rather than by the chemical constituents of the crystal, the reaction is said to be topochemically controlled. The nature of products obtained in a decomposition reaction is frequently decided by topochemical factors, particularly when the reaction occurs within the solid without separation of a new phase (Thomas, 1974 Manohar, 1974). A topotactic reaction is a solid state reaction where the atomic arrangement in the reactant crystal remains largely unaffected during the course of the reaction, except for changes in dimension in one or more directions. Dehydration of Mo03-2H20 is a typical example of a topotactic reaction ... 

The current paradigm in chemistry celebrates the existence of physical entities called chemical atoms (now known simply as atoms). John Dalton (1766-1844) looked at the material world in which he hved and visualized it in terms of a set of different material objects of small size and combining capacity (7). He called these particles atoms in his New System of Chemical Philosophy (1808). Others, such as Humphry Davy (1778-1829), were not yet willing to see the world in this way. Dalton combined both a partictrlar theory of nature and specific observatiorrs to arrive at his views. The present paper will examine some episodes in the history of chemistry that enabled other chemists to see atoms as appropriate chemical constituents of our world. The view of what constitutes a chemical atom has changed during the time period from 1808 to 2008, but the common theme requires a context in which actual measurements can be viewed as evidence for atoms. ... 

In addition to the presence of natural coumarin derivatives, phytochemical analysis found that dong quai also contains ferulic acid and osthole as ingredients. Ferulic acid was reported to have antithrombotic activity (38). Similarly, study using the closely related Angelica pubescens also found osthole to be antithrombotic (39). These two chemical constituents exert their antithrombotic effects by interfering with different pathways responsible... 

Maries, R. J., C. Clavelle, L. Monteleone, N. Tays, and D. Burns. 1999. Aboriginal Plant Use in Canada s Northwest Boreal Forest. UBC Press. Vancouver, Canada. 368 p. Hetherington, M. and W. Steck. 1997. Natural chemicals from northern prairie plants the phytochemical constituents of one thousand North American species. Fytokem Products. Saskatoon, SK. 

---