Extraction from Natural Sources

Tocopherols and tocotrienols used for supplementation of foods and feeds or production of nutraceuticals, e.g., pills and powders, are obtained either by extraction from natural sources or by chemical synthesis (Schuler, 1990 O Leary, 1993). Extraction of tocopherols and tocotrienols from natural sources is economically feasible only if tocopherol/tocotrienol-rich raw materials are available at large quantities and are of high quality. In production of both natural and synthetic compounds, there are several extraction and purification processes that have to be optimized and controlled. Moreover, the environmental impacts of these processes should be acknowledged. Technological innovations in these areas are constantly needed. 

Natural tocopherols and tocotrienols have the 2R, 4 R, 8 R and 2R, h -trans, T-trans configurations, respectively, while synthetic products are racemic mixtures. Natural and synthetic products have similar potentials as antioxidants, but natural products have higher vitamin E activity than synthetic ones. Production capacities of natural and synthetic tocopherols and tocotrienols are enlarging (ANON, 1998). In 1991, the world production of vitamin E compounds was 6800 tons (O Leary, 1993). 

Palm fatty acid distillate (PFAD) is a valuable by-product of palm oil processing, from which the production of tocopherols and tocotrienols is technically feasible (Ong and Choo, 1997). PFAD is wildly abundant, as palm oil is the second largest oil produced in the world. It contains 4000-8000 pg/g total vitamin E compounds, which is up to 10 times as much as crude palm oil contains (Tan, 1989 Ong and Choo, 1997). The tocopherol and tocotrienol profiles of PFAD and crude palm oil are similar, consisting of about 85% of tocotrienols, i.e., y-tocotrienol a-tocotrienol 8-tocotrienol (Tan, 1989). Because of cholesterol-lowering properties (Lane et al., 1999), the high level of tocotrienols makes PFAD an important source, because most other natural sources are devoid of tocotrienols. Fatty acids and esters, sterols and squalene are removed from PFAD as described above. Finally, the vitamin-E-rich product is purified and deodorized to yield a tocopherol/tocotrienol-rich product of 95-99% purity. 

Oil extracted from rice bran and com fiber is especially rich in tocopherols, tocotrienols and sterols. Extraction of these valuable compounds is remarkably enhanced by heat pretreatment (Lane et al., 1999). For example, the level of extracted y-tocophcrol increased from 0.3% to 3.6% by subjecting com fiber to temperatures of 100-175°C (Moreau et al., 1999). Tocopherol- and tocotrienol-rich oils may be used as such as important sources of vitamin E, or the vitamers can be purified from them following the same protocols as above. 

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Aroma. Chemicals. Specialty chemicals produced either by extraction from natural sources or by synthesis, such as vanillin [121 -33-5],... 

Development of an economically viable production process for fohc acid either by genetically engineered microorganisms or by extraction from natural sources is not yet feasible. 

To date, the lipids so far used have been mainly extracts from natural sources such as EPC and archaeal lipids[17,18] The chemical stability of EPC, however, is not sufficient and the membrane permeability to H1 is sometimes too high for quantitative analyses of membrane protein functions. Though archaeal lipids display many preferable features for... 

Einally, another group of oligosaccharides that have attracted attention for their potential anti-adhesive activity are the mannooligosacchar-ides (MOS). The MOS can be extracted from natural sources, produced... 

Historically, plants and other living creatures have been used as medical treatments, and early chemically produced drugs were based on or identical to compounds extracted from natural sources. Nature continues to provide modern drugs, and searches stiU begin with systematic laboratory testing or by following clues from traditional folk healers. Modern chemical methods are used to improve upon what is foimd in nature. Some of these drugs, such as paclitaxel, provide major improvements in medical care. 

Extraction from natural sources (plant or animal material) ... 

Most active principles and pharmaceutical forms are processed in the presence of organic solvents or reagents. The current regulations on products generally restrict to a few p.p.m. the amount of residual solvent. This very low concentration level could favour the CO2 utilization when non-polar compounds have to be eliminated. On the other hand, the elimination of residual solvents from tablets, films or other pharmaceutical preparations in which organic solvent are involved has been addressed [15]. Another application is related to the removal of residues from medical materials such as monomers, additives or polymerization residues from polymers or elastomers. Purification of active principles includes elimination of other undesired molecules pesticides from some vegetal extracts, and antibacterials suspected of toxic co-extracts from natural sources. 

Historically, the dye industry has been closely linked with the development of synthetic organic chemistry. Although dyes have been extracted from natural sources for centuries, it was not until 1856 that a synthetic dye was produced commercially. The previous year, William Henry Perkin—at age 17 —oxidized... 

It would be too dangerous to taste a liquid to find out if it was acidic. Chemists use substances called indicators which change colour when they are added to acids or alkalis. Many indicators are dyes which have been extracted from natural sources, for example litmus. 

Carotenoid pigments can be extracted from natural sources or synthesized and are used to fortify and color foods. During the... 

Biopharmaceuticals are proteins and nucleic acid-derived molecules that are used for therapeutic purposes or in vivo diagnostics, and are produced by means other than direct extraction from a native (non-engineered) biological source (Walsh, 2002). When considered together with vaccines and biomolecules extracted from natural sources, they are designated biologicals by the pharmaceutical industry. 

In the recent years, standardization and characterization of allergen extracts from natural source have been improved, but extracts are often heterogeneous and may contain a mixture of nonallergenic molecules and relevant allergens which can vary in composition and quantity (Chapman et al. 2002). Molecular biology could be the... 

Okayama, Japan. He reported his new enzyme system in 2002, which he had extracted from a bacterium. This will convert starch to trehalose in high yields, bringing down its cost to 1% of what it had been when it was extracted from natural sources such as yeast. Hayashibara also reported that trehalose suppresses human body odour, especially that given off by old people who produce the somewhat odorous chemicals 2-nonenal and 2-octenal41)in their skin. When they use a 2% solution of trehalose as a body lotion it reduces the emission of these smelly compounds by about 70%. Maybe one day it will find cosmetic uses and no doubt be added to deodorants and body lotions, as the following advert from the future shows ... 

The main drawback of glycoprotein isolation and extraction from natural sources is the complexity of purification arising from their expression as mixtures of different glycoforms [6], These protein isoforms differ only with respect to the number, type of attached gly cans, or gly cosy lation site yet may result in many hundreds of variants. Homogeneous glycoforms cannot be readily accessed from natural sources because glycosylation, as with other posttranslational modifications, is not directly genetically driven. 

Vitamin C, classified as either a pharmaceutical [5] or a food additive [6], has annual sales of 325 million dollars, the largest of all pharmaceuticals produced [7]. Pharmaceuticals, in general, lead in profitability for all industries [6]. Although vitamin C can be extracted from natural sources, it is primarily synthesized. In fact, it was the first vitamin to be produced in commercial quantities [6]. Jaffe [8] outlines the synthesis. Starting with D-glucose, vitamin C is produced in five chemical steps, one of which is a biochemical oxidation using the bacterium Acetobacter suboxydans. D-glucose is obtained from cornstarch in a process, which will be described later. 

D2 and D3 vitamins (ergocalciferol and cholecalci-ferol) has not been equally successfulJ Vitamin D extracted from natural sources has a single conformational stereochemistry that is one of several isomers produced in synthetic preparations. To certify that the natural form is present in a synthetic product, where it can be accurately assayed in the presence of the other isomers, is a formidable analytical task. Whether direct CD detection can satisfactorily solve it is currently unknown. A prior non-selective derivati-zation reaction might be required on all isomers. The A and E vitamins are achiral and not subject to chiroptical detection unless first derivatized by reaction with a chiral host. 

Contaminants, particularly heavy metals, are a problem in certain herbal preparations, but in nutraceuticals, breakdown products, synthetic intermediates, and co-occurring related constituents extracted from natural sources are also possible contaminants. Specific contaminants may be evident in particular products, such as alkanol esters in policosanol, and DMSO in MSM, due to manufacturing or extraction problems. 

Plutonium is extracted from natural sources only rarely and only for the purposes of research. 

Sodium sulfate is an important heavy chemical in the chemical industry and is found in many mineral deposits. The world reserves are so large that with the present rate of consumption they are sufficient for several hundred years. In addition to extraction from natural sources, it is also produced in large quantities as a byproduct e.g. in the production of potassium salts, sodium chloride and borax and in chemical and metal producing processes. Dedicated manufacture e.g. from sodium chloride and sulfuric acid has become less important. 

Cannabis preparations in the form of marihuana, hashish, etc. have been known and used for many years for their psychoactive and therapeutic properties. The major active constituent of the resin which is exuded by the female plants of Cannabis sativa L. is (-)-6a,10a- rans-1 - hydroxy-3-n-pentyl-6,6,9-trimethyl-6a,7,8,l Oa-tetrahydr odibenzo[b,d]pyran, also known as (-)-6a,10a- rans-A-9-tetrahydrocan-nabinol or A9-THC. The structure and absolute configuration of this material was first reported by Gaoni et al. in J. Amer. Chem. Soc., 86, 1646 (1964). Since that time considerable research has been directed towards the preparation of this compound via a synthetic method, thereby eliminating the need to obtain the material by extraction from natural sources. 

A major problem of cell-based screening assays is that cytotoxicity derived from mechanisms unrelated to the target of interest prevents further evaluation of a compound or, more feasible, of an extract from natural sources. Furthermore, depending on the assay endpoint, false positives may be selected. Therefore, secondary assays are required to eliminate cytotoxic false positives as well as to prove the mode of interaction that gave positive endpoint detection in the screening assay. 

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