Plant extracts detection types

A liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed to detect tumor-promoting diterpene esters of the tigliane and ingenane types within plant extracts. Fractionation on a Cig HPLC column was followed by MS-MS-multiple reaction monitoring (MRM). 

These types of DNA detection can also be applied to studies of antioxidative properties of various natural substances preserving DNA from damage [49, 50]. The detection scheme exploits quantification of the DNA portion that survives previous incubation of the biosensor in a mixture of the DNA cleavage agent and antioxidant/mixture of antioxidants under investigation. Using this approach, yeast polysaccharides, phenolic acids such as rosmarinic and caffeic acids, selected flavonoids, as well as aqueous plant extracts and tea extracts were studied [51]. 

Rotation planar chromatography (RPC), as with OPLC, is another thin-layer technique with forced eluent flow, employing a centrifugal force of a revolving rotor to move the mobile phase and separate chemical compounds. The RPC equipment can vary in chamber size, operative mode (analytical or preparative), separation type (circular, anticircular, or linear), and detection mode (off-line or online). The described technique was applied in analytical and micropreparative separation of coumarin compounds from plant extracts. 

Hexahydroxydiphenic acid in a bound form (3) is readily detected in a plant extract by an old but very distinctive color test - the Procter-Paessler reaction. Esters of type 3 react with nitrous acid to give a carmine or rose red, changing to brown-green, then purple, and finally indigo blue. The chemical basis of this reaction has not been discussed but it has been employed by Bate-Smith (6, 7) for the quantitative determination of 3 in plant extracts, and it forms the basis of a very useful spray reagent for the detection of 3 by paper chromatography (6, 7, 43). 

In general, the polyacetylenes known to be antibiotic were not recognized first as polyacetylenes, then tested for activity, but rather the reverse. Antibacterial activity was observed in a fungal or plant extract, and when the active principle was isolated and characterized, it proved to be a polyacetylene. Of the following examples, the first five were detected as the result of the earhest surveys of Basidiomycetes for antibiotic activity, (Wilkins and Harris, 1944 Robbins et al., 1945 Hervey, 1947), the last four as the result of isolated investigations of antibiotic principles from three different types of organisms. 

Because the protein analyte is endogenous to the plant, it can be difficult to demonstrate the efficiency of the extraction procedure. Ideally, an alternative detection method (e.g., Western blotting) is used for comparison with the immunoassay results. Another approach to addressing extraction efficiency is to demonstrate the recovery of each type of protein analyte from each type of food fraction by exhaustive extraction, i.e., repeatedly extracting the sample until no more of the protein is detected. " ... 

The quantity, quality and purity of the template DNA are important factors in successful PGR amplification. The PGR is an extremely sensitive method capable of detecting trace amounts of DNA in a crop or food sample, so PGR amplification is possible even if a very small quantity of DNA is isolated from the sample. DNA quality can be compromised in highly processed foods such as pastries, breakfast cereals, ready-to-eat meals or food additives owing to the DNA-degrading action of some manufacturing processes. DNA purity is a concern when substances that inhibit the PGR are present in the sample. For example, cocoa-containing foodstuffs contain high levels of plant secondary metabolites, which can lead to irreversible inhibition of the PGR. It is important that these substances are removed prior to PGR amplification. Extraction and purification protocols must be optimized for each type of sample. 

Experiments to identify disinfection by-products (DBFs) have been carried out using two different procedures. In the first, natural waters (e.g., river, lake) are reacted with the disinfectant, either in a pilot plant, an actual treatment plant, or in a controlled laboratory smdy. fii the second type of procedure, aquatic humic material is isolated and reacted with the disinfectant in purified water in a controlled laboratory study. This latter type of study is relevant because humic material is an important precursor of THMs and other DBFs. Aquatic humic material is present in nearly all natural waters, and isolated humic material reacts with disinfectants to produce most of the same DBFs found from natural waters. Because DBFs are typically formed at low levels (ng/L-pg/L), samples are usually concentrated to allow for DBF detection. Concentration methods that are commonly used include solid phase extraction (SFE), solid phase microextraction (SFME), liquid-liquid extraction, and XAD resin extraction (for larger quantities of water) [9]. 

Poinar and colleagues (72) successfully extracted DNA from three human coprolites made by Native Americans in Hinds Cave, Texas more than 2,000 years ago. Not only were they able to extract human mtDNA from the coprolites, which were determined to belong to known Native American mitochondria] types, but they also were able to analyze DNA from the plants and animals eaten by these occupants of Hinds Cave. Importantly, they discovered that some of the species of plants and animals identified by molecular techniques were not detected in the same feces by macroscopic techniques (and some macroscopically identified species were not detected by the DNA analysis). The combination of the molecular and macroscopic evidence demonstrated that these three Native Americans had a diverse and well-balanced diet. 

Triazole type, pyrimidine type (retardants) Plants Ethylene dichloride extraction Silica gel chromatography with N-thermionic detection [169]... 

A large variety of nonalcoholic beverages claim the presence of plant and fruit extracts. If so, they should contain some amounts of original proteins even if they are extremely diluted with the addition of water. A number of them have been analyzed for their proteomics profile, but due to large dilution, a preliminary treatment with CPLL was applied. To date, studies on these types of proteomes are very rare perhaps, the most compelling data are about the detection of peptides as described by Kasicka (64). 

Se Speciation in Plants The presence of a number of volatile Se species was reported in edible allium plants such as garlic by GC-AES [79]. Selenomethionine, Se-methylselenocysteine, and y-glutamyl-Se-methyl-L-seleno cysteine were identibed in garlic and onion by HPLC-ICP-MS and ES-MS/MS [80]. Selenomethionine is the primary species found in all types of nuts (19D25 percent of the total Se) [30], sunBower [81], and mushrooms [36, 37], The distribution of Se among different fractions (lipid extract, low molecular weight, and protein fractions) of nuts and speciation analysis was studied [30]. Selenium was not detected in any of the lipid extracts obtained from the different types of nuts [30], Results obtained for Brazil nuts by SEC with on-line ICP-MS detection showed that approximately 12 percent of total Se was weakly bound to proteins [30],... 

When we attempt to extract defense substances, sometimes we assume that the substances are ubiquitously present in plant tissues. However, recent studies show that quite often this is not the case. Without being aware of this fact, we might fail to detect and extract defense substances. Here, three types of such defense systems are introduced. 

APCI has become a popular ionization source for applications of coupled HPLC-MS. Figure 1.33 shows an example of an application of HPLC-APCI coupling [79]. It shows the analysis obtained from extracts of maize plants. Six compounds are identified by mass spectrometry. These compounds have been identified as glucoconjugated DIMBOA (2,4-dihydroxy-7-methoxy-l,4-benzoxazin-3-one) and similar molecules that differ by the number of methoxy groups in the benzene ring and/or by the N-O methylation of the hydroxamate function. This example clearly shows the influence of the analyte on the type of observed molecular species. Indeed, the presence of an acidic group in the compound from peak 1 allows mainly the detection of deprotonated molecular ions, whereas the compound from peak 4 does not contain an acid group and thus leads only to the formation of adduct ions. 

ELISA could potentially be used advantageously in many types of exposure and monitoring situations, for paraquat and other pesticides amenable to ELISA analysis. An obvious use of ELISA is the detection of pesticide residue levels in plant and animal tissues, or food extracts. Biological specimens such as plasma and urine currently analyzed by RIA seem particularly amenable to analysis by ELISA. Portable field kits could be developed to determine safe worker re-entry times into treated fields. Environmental samples such as soil, water, and air, can be analyzed by the ELISA. Pesticide conjugates have been proposed for skin testing of individuals suspected of sensitivity to pesticides (fi.) the ELISA could be used to detect specific antibodies in these individuals and aid in exposure studies. 

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