Proanthocyanidins organisms

When appreciable amounts of pectin, proteins, lipids, unwanted polyphenols, or other compounds are suspected to be present in anthocyanin-containing extracts, some of them can be precipitated or the anthocyanins may be crystalhzed and separated from the others. Pectin and proteins can be removed by organic solvents such as methanol and acetone in order to reduce their solubility, then precipitated and separated by centrifugation. Gelatin was used to remove proanthocyanidin due to its high molecular weight. Anthocyanins were reported to be precipitated early by lead acetate to achieve isolation from other materials. ... 

K.W. Singletary and B. Meline, Effect of grape seed proanthocyanidins on colon aberant crypts and breast tumors in a rat dual-organ tumor model. Nutr. Cane. 39 (2001) 252-258. 

This purification step is designed to remove impurities from the proanthocyanidin extract. It utilizes liquid-liquid extraction to remove lipophilic material and monomeric flavan-3-ols, and also adsorption chromatography to remove more hydrophilic material such as organic acids, sugars, and residual flavan-3-ol monomers. Following the steps in this protocol, purified and powdered proanthocyanidins are obtained. 

The potential impurities will vary according to the plant tissue extracted, and therefore the exact washing volume will vary. It is important to determine the impurities present and their retention properties on the column to minimize impurities in the final proanthocyanidin and maximize proanthocyanidin recovery. For this step, the use of a spectrophotometer is helpful in monitoring the eluate. Some typical impurities and monitoring wavelengths include organic acids (215 nm), flavan-3-ol monomers (280 nm), hydroxycinnamic acids (320 nm), andflavonols (365 nm). Anthocyanins are observable in the visible spectrum. 

Free radicals might be involved in the incidences of various diseases such as arthritis, hemorrhagic shock, atherosclerosis, advancing age, ischemia and reperfusion injury of many organs, Alzheimer and Parkinson s disease, gastrointestinal dysfunctions, tumor promotion and carcinogenesis, AIDS, and other human health problems [85]. The oxidative proanthocyanidins as antioxidants could quench the free radicals and might help to enhance the action of other antioxidants such as vitamin C. 

The rotational and conformational isomerism in dimeric proanthocyanidines 101 was studied by NMR spectroscopy. It was found that the geometry of these important polyfla-vanoids depends on the nature of the solvent (in organic solvents and water). The effect of the Y atom and the substituents X on the planarity and the barrier to internal rotation about the aryl-Y bond were estimated by semiempirical quantum-chemical calculations... 

Jannie P. J. Marais studied at the University of the Free State, Bloemfontein, South Africa where he obtained his Ph.D. in organic chemistry in 2002. His research focused on characterization of the free phenolic profile of South African red wine, and the stereoselective synthesis of flavonoids, for example, flavan-3,4-diols and flavanones. He joined the National Center for Natural Products Research at the University of Mississippi as a postdoctoral associate in July of 2002, where he worked with Dr. Ferreira on the stereoselective synthesis of flavonoid precursors, the semi-synthesis of proanthocyanidin oligomers, characterization of proanthocyanidin profiles of selected transgenic plants, and the synthesis of radioactive antimalarial 8-aminoquinolines. He was promoted to associate research scientist in 2005, where his main area of research still remains the synthesis of A- and B-type proanthocyanidins, starting at the monomeric level and continuing through the tri- and tetra-meric, to the deca-mer level. 

The main classes of phenolic compounds found in fruits are (1) phenolic acids, (2) stilbenes, (3) lignans, (4) flavonoids, and (5) tannins or proanthocyanidins. These classes are the most abundantly occurring phenolic compounds which are also an integral part of everyday dietary antioxidants in populations worldwide [7]. The most abundant phenolic compounds in the diet are phenolic acids (benzoic and cinnamic acid derivatives) and flavonoids which account for 60% and 30%, respectively, of total dietary phenolic compounds [7]. These phenolic compounds may be associated with various carbohydrates and organic acids and with one another (Figure 2 Table 1). 

Phytochemistry Rhizomes contain carbohydrates (glucose, arabinose, and ketose), pectins, organic acids (6.46 %), essential oils, saponins, alkaloids, vitamin C, and tannins. The leaves contain vitamin C, carotene, and tannins. The flowers contain tannins (7.35 %) and the fruits contain carbohydrates (Blinova 1957 Aliev et al. 1961). The roots were found to contain small amounts of proanthocyanidins and high amounts of ellagic acid (Oszmianski et al. 2007). 

Phytochemistry Underground organs contain up to 28-35 % tannins, mainly of the pyrocatechin group (proanthocyanidin Ogolevitz 1951). Many proanthocyanidins have been isolated from the roots (Makhmatknlov et al. 1992,1994 Keneshov et al. 1997a, b). The leaves contain flavonoids (Chumbalov and Omurkamzinova 1968). 

The Type 1 proanthocyanidins are distributed almost ubiquitously in the woody plants, whereas Type 2 proanthocyanidins are confined to certain families in the Leguminosae and Anacardiaceae (see Sect. 7.7.3.1), often co-existing with Type 1 proanthocyanidins either in the same or different organs of the plant. However, the Type 2 tannins are of pre-eminent importance commercially as currently the two most important sources of condensed tannins for industrial applications are wattle Acacia mearnsii) bark and quebracho Schinopsis spp.) wood, which are both of this type (Chap. 10.3). Our current knowledge of these tannins is almost entirely due to the efforts of David Roux and his colleagues over the past three decades. 

Senescence in leaf tissue leads to a general desiccation of the organ and consequent breakdown of the cells. Possibly proanthocyanidins are further polymerized by the native oxidase enzymes of the leaf, and hence rendered insoluble. 

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