The tannin composition of wood of Ceratonia siliqua (carob) was studied using GC-MS and classical chemical assays. Aqueous methanolic extracts of carob heartwood and sapwood were fractionated using organic solvents of increasing polarity, and GC-MS analyses were performed before and after hydrolysis. Prior to hydrolysis, gallic acid, catechin and its derivatives, methyl inositol and chalcone were determined as the major compounds found in the free form. Aqueous fractions of both wood types were hydrolysed with hydrochloric acid in methanol and extracted with organic solvents and water. These fractions were rich in methyl inositol, gallic acid, glucose and other monosaccharides. The results show that carob wood contains predominantly gallotannins and proanthocyanidins. The technique employed is shown to be a valuable tool and an alternative method to HPLC determination of hydrolysable tannin composition.
The bark and wood of an endemic oak species in Turkey, Q. vulcanica, were investigated with regard to main components, phenolics as well as extractives. About 66 % of extract free wood consists of polysaccharides, i.e. cellulose and polyoses. Heartwood was found to be rich in ellagitannins, while in bark proanthocyanidins occurred in larger amounts. Extractives soluble in cyclohexane were divided into saponifiables and neutrals. Among saponifiables saturated acids made up the majority, while sterols and nonsteroidal triterpenes were the predominating compounds of the neutral fraction.
The hot water-and total acidity of some important hardand softwoods were correlated to hot water and 1% alkali solubilities. In this manner a positive correlation exists and in case of hardwoods a plot, an expected increasing curve, can be observed. However, due to an insuf®cient number of data the correlations of softwoods are somewhat ambiguous for low acidities and solubilities. Furthermore, the hot water solubility data ®t better than those of alkali solubility to both bound and total acidity.
Korrelation der Holz-Acidita Èt mit der Ausbeute an Heiûwasser-und Alkali-ExtraktenDie Heiûwasser-und die Gesamt-Acidita Èt einiger wichtiger Laub-und Nadelho Èlzer wurde korreliert mit der Lo Èslich-keit in Heiûwasser und Alkali. Es existiert eine positive Korrelation. Im Fall der Laubho Èlzer liegt eine stetig ansteigende Kurve vor. Fu Èr geringe Lo Èslichkeiten und geringe Acidita Èt ist diese Korrelation allerdings aufgrund des geringen Datenmaterials recht schwach. Die Lo Èslich-keit in Heiûwasser ist in beiden Fa Èllen besser korreliert als die Alkali-Lo Èslichkeit, und zwar sowohl zur gebundenen Acidita Èt als auch zur Gesamt-Acidita Èt.
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