Extraction and isolation compounds

The antimicrobial, anti-inflammatory, wound healing and antioxidant activities of the plant have been documented (26, 29, 30). Various extracts and isolated compounds showed antimicrobial activity. Irobi (31) showed that the ethanolic extract of the plant had bactericidal effect on reference microbial strains and hospital isolates including Bacillus thuringiensis (var Israeli), Bacillus stearothermophilus (NCTC 10339), Staphylococcus aureus (NCTC 6571), Escherichia coli (NCTC 11699), Pseudomonas sp.. Streptococcus faecalis and Klebsiella sp. Isosakuranetin, 4 -hydroxy-5,6,7-... 

Table 7. Total Reactive Antioxidant Potential (TRAP) and Total Antioxidant Reactivity (TAR) in (M Trolox Equivalents Number of Radicals (n) Trapped Per Molecule of Additive, ICso s and Percentage of Efficiency, Obtained From the Quenching of Luminol Chemiluminescence in Methanolic Extracts and Isolated Compounds of Pothomorphe spp.

Jayaprakasha and Rao (2000) extracted with benzene and acetone the lichen Parmotrema stuppeum in order to investigate its antioxidant effect. Both the extracts were fractionated on 1 % oxalic acid impregnated silica gel column to obtain methyl orsenillate, orsellinic acid, atranorin and lecanoric acid, respectively. Antioxidant activities of benzene extract, acetone extract and isolated compounds were evaluated in a carotene-linoleate model system. The obtained results showed that the pure compounds and extracts have moderate antioxidant activity. 

Uncaria spp. has been widely used in the form of decoctimis made from single species or from herbal formulations in traditional systems of medicine to treat several disorders as discussed in previous sections. Among all, the species of Uncaria, U. tomentosa is the widely studied species which is followed by U. rhynchophylla. The pharmacological activities of cmde extracts and isolated compounds are discussed in the following subsections. 

Incorporating the Kirtas system with the International Plant Names Index and SNOW-MED allows movement of the historic text into an electronic format, identihcation of current plant names, and identihcation of the symptoms treated with the plants. To complete the mining of historic herbal texts for novel drug leads we use the Natural Products Alert (NAPRALERT ) database to compare the information extracted from the historic herbal text to the reports of plant use in the current literature. The NAPRALERT database provides a summary of plants ethnopharmacological use, biochemical activities, and isolated compounds [27]. By querying each plant (with the current plant name) it is possible to identify any reports in the current literature regarding the plant. As an example, Table 4.1 shows the NAPRALERT output for Cycas rumphii. 

Tan [71] devised a rapid simple sample preparation technique for analysing polyaromatic hydrocarbons in sediments. Polyaromatic hydrocarbons are removed from the sediment by ultrasonic extraction and isolated by solvent partition and silica gel column chromatography. The sulphur removal step is combined into the ultrasonic extraction procedure. Identification of polyaromatic hydrocarbon is carried by gas chromatography alone and in conjunction with mass spectrometry. Quantitative determination is achieved by addition of known amounts of standard compounds using flame ionization and multiple ion detectors. 

Compound extraction and isolation The raw propolis (155 g) was soaked in 90% aqueous ethanol (1 L) for 1 week and the extraction was repeated twice. 

Application of the MAS to drinking water should considerably broaden the scope of organic compounds detected and measured, relative to previously available analytical methods. This conclusion is especially true for the polar compounds of relatively low MW (<500) however, a few of these compounds are not recovered well by the MAS extraction and isolation techniques or are not gas chromatographable, even after derivatization. HPLC methods offer the most promise for separation and analysis of these compounds as well as those of high molecular weight. 

Polyphenolics constitute a wide range of chemical compounds composed of aromatic ring(s) with one or more hydroxyl substituents, including their functional derivatives. Methods for extraction and isolation of polyphenolics from plant material are described in this unit. Extraction and isolation are the first important steps for separation, characterization, and quantification of polyphenolics from plant material. Polyphenolics are often most soluble in organic solvents less polar than water. The solubility is dependent on the polar properties of the polyphenolics. The correct selection of the extracting solvent is not as simple as it may seem. Aqueous methanol is a popular choice of solvent (see Background Information). 

Scheme 2 Extraction and isolation of compounds from B. rigidum...

Antibacterial activity of extracts and isolated constituents of P. sidoides was evaluated against three gram-positive and five gram-negative bacteria (707). Most compounds exhibited antibacterial activities. Further investigations complement these findings 108). 

PHARMACOLOGICAL EFFECTS The type of extract or preparation can be important since alcoholic extracts are unlikely to contain polysaccharides, whereas aqueous extracts may not contain the lipophilic alkamides. Tests have been performed with the pressed juice, alcoholic extracts and isolated pure compounds. Effects such as increased phagocytosis as measured by the carbon clearance test, macrophage activation,... 

To date, cyanobacteria have rarely been reported to produce exclusively sugar-based secondary metabolites, such as the aminoglycosides or aminocyclitols typical of the actinomycetes. Flowever, it should be noted that part of the reason for their underrepresentation may be the fact that many natural products chemists do not focus on water-soluble metabolites, and thus standard extraction and isolation protocols strongly select against the isolation of polar, sugar-based compounds. 

This analytical project was undertaken as part of the Generessence program at International Flavors Fragrances Inc. The program involves the in-depth analysis of a natural product to enable the creation of closer to nature flavors, using only the chemicals found in the analyses. An additional aim is the discovery of novel compounds in the natural product and occasionally in nature for the first time that may be synthesized and ultimately registered for use. Therefore, as much detail as possible is required for the analysis of volatiles, semi-volatiles and even non-volatiles present. Many extraction and isolation... 

To isolate active compounds it is necessary to monitor the activity during fractionation and isolation. In the case of triterpenes as anti-inflammatory agents, different kinds of tests are employed. Subplantar administration of carrageenan in rats was commonly used in earlier studies to establish the anti-inflammatory activity of orally administered plant extracts or fractions, but a large amount of sample was necessary. Topical application of inflammatory agents is more useful in screening extracts and pure compounds, because the amount of sample is smaller than with oral application and it is easier to track the activity. The introduction of in vitro tests could be an alternative way to monitor the anti-inflammatory activity. 

Naton, S., Ikekawa, N., and Suzuki, M. (1981) Advances in Natural Products Chemistry. Extraction and Isolation of Biologically Active Compounds Halstead, Wiley, New York... 

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