Quebracho, Schinopsis

Vivas, N. et al.. Differentiation of proanthocyanidin tannins from seeds, skins and stems of grapes Vitis vinifera) and heartwood of Quebracho (Schinopsis balansae) by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and thioacidolysis/liquid chromatography/electro-spray ionization mass spectrometry. Anal Chim. Acta, 513, 247, 2004. 

The gluing experiments were done with commercially available starch, proteins (casein, glutin) and tannins of mimosa Acacia spp.), Pinus radiatay and quebracho (Schinopsis spp.) and with tannins extracted from the bark of spruce (Picea abies) and common pine (Pinus sylvestris). The extractions were carried out with water or organic solvents under alkali and/or sulphite conditions on a laboratory scale aiming at optimization of yield and polyphenolic extract content. After extraction, the solutions were concentrated under reduced pressure and freeze dried. One pine bark extract was modified with phenol. A summary of the tannin extracts and their properties is given in Table I. 

The profisetinidins are the most important proanthocyanidins of commerce, constituting the bulk of wattle Acacia meamsii) and quebracho Schinopsis species) tannins. Their natural occurrence, general synthesis protocols, and chemical transformations, especially under basic conditions, were comprehensively reviewed in Ferreira et al.l Ferreira and Li," Porter, Hemingway, and Ferreira and Bekker. ... 

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. 

Approximately 200000 tons of quebracho Schinopsis sp.) and 100000 tons of wattle (Acacia mearnsii) tannins are produced world-wide annually. Although statistics are not so accurate, about 200000 tons of vegetable tannins derived from other plants such as hemlock (T uga sp.), chestnut (Castanea sp.), oak (Quercus sp.) and myrobylan (Terminalia sp.) extracts add to this for a total world production thought to be about 500000 tons per year, (see also Chap. 1.1). 

Trees of the genus Schinopsis. native to the southern part of South America, including southern Brazil, Bolivia and other southern countries are very important source of tannin. These trees are known by the name quebracho, which means ax-breaker, because of their very hard, dense, heavy, dark-red wood, which is cut with difficulty. The heartwood of the tree contains 20-27% tannin, which is obtained by cutting the wood into small chips and extracting with water. Tilts tannin is often used in combination with tannins from other plants. 

Condensed tannins constitute more than 90 per cent of the total world production of commercial tannins (200000 tons per year) [11]. Their high reactivity towards aldehydes and other reagents renders them both chemically and economically more interesting for the preparation of adhesives, resins and other applications apart from leather tanning. The main commercial species, such as mimosa and quebracho, also yield excellent heavy duty leather. Condensed tannins and their flavonoid precursors are known for their wide distribution in nature and particularly for their substantial concentration in the wood and bark of various trees. These include various Acacia (wattle or mimosa bark extract), Schinopsis (quebracho wood extract), Tsuga (hemlock bark extract), Rhus (sumach extract) species, and various Pinus bark extract species, from which commercial tannin extracts are manufactured. 

Fisetinidol (2A,3S (Schinopsis quebracho-col-oradoh (-i-Fisetinidol (2ff,3/i) Acacia meamsii). 3,7,3, 4, 5 -Pentahydroxy-flavan ... 

The profisetinidins have been studied intensively by Roux s school at The University of the Orange Free State, Bloemfontein, South Africa. The heartwoods of Acacia mearnsii and Colophospermum mopane contain a series of 2R isomers and these compounds have all been synthesized (Tables 7.6.9 and 7.6.10). The commercially important quebracho tannins from Schinopsis and Rhus contain a series of 2S isomers and these compounds have also been synthesized recently. Fifteen dimers, nine trimers, and nine tetramers have now been thoroughly de-... 

Engl. Schinopsis quebracho- Sch.que 26 28 54 Chacoan pole Monocentric... 

The DAENO of occurrences reveals six vegetation communities in Paraguay, distributed in the two biomes and separated by one ecotone (Figure 8.2). The chaco is composed of three communities (Figure 8.2b) the typical facies of the xeromorphic forests of the chaco at the extreme west (A2) the psammophilous facies (related to sandy soils), with Schinopsis quebracho-colorado (Schltdl.) F.A. Barkley E. Mey, (Al) and the wet chaco on the west side of the Rio Paraguay (AO). 

The monocentric species (Araucaria angustifolia, Aspidospertna quebracho-bianco, Nectandra megapotamica, Schinopsis balansae and S. quebracho-colorado) are present along the axis from pole A to pole C. They are characteristic of Chacoan and Paranean poles. Because of their narrow... 

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