Bark, chemical composition

Despite the complexity of the chemical composition of the resinous materials, in a few minutes such techniques provide a mass spectral fingerprint, which highlights the compounds that are the main components in the sample. They avoid any sampling treatment before analysis. They have thus enabled diterpenoid resinous materials from Coniferae, and several triterpenoid materials to be clearly identified. In particular, the DE-MS technique is able to distinguish between different triterpenoid materials such as mastic resin, frankincense resin and birch bark tar. In fact, using PCA on DE-MS mass... 

The chemical composition of birch bark tar is dependent on the temperature at which tar is produced. In producing simulated tars in the laboratory for comparison with an adhesive used to repair a Roman jar from Stan wick, Charters et al. (1993) found that tars prepared at 350 °C displayed an increase in triterpenoid hydrocarbons as well as unresolved components presumably resulting from pyrolysis, although the precise nature of these molecules has not been elucidated. Binder et al. (1990) and Charters et al. (1993) also report the presence of allobetul-2-ene [Structure 7.24] in aged birch bark tars. Since this molecule has not been reported in extracts from fresh birch bark, it could be formed during heating to produce the tar (Regert et al., 2003). 

Indonesian cassia of commerce is the dried bark of C. burmannii. Most of the bark produced is exported and domestic consumption is very small. The main importing countries are the USA, Germany and the Netherlands. The chemical composition of Indonesian cassia was thought to be similar to that of Chinese cassia, but later studies showed the existence of various chemotypes. 

The chemical composition of bark is complicated, varies among the different tree species and also depends on the morphological elements involved. Many of the constituents present in wood also occur in bark, although their proportions are different. Typical of bark is its high content of certain soluble constituents (extractives) such as pectin and phenolic compounds as well as suberins. The mineral content of bark is also much higher than that in wood. 

In Table 1 the chemical composition of the cork used in this work is presented. It shows that the material used contains lignocellulosic tissues, probably from the phloemic remains of the cork bark in the planks used for the production of stoppers The extraction percentages of the cork constituents were calculated based on the amount of constituents initially present in the extractive - free cork... 

The results are given in Tables 2 and 4 completed with the data of ash chemical composition [8], Accordingly, the results showed that ash sintering was dependent on the pressure of steam. For spruce bark, willows and alfalfa, as shown in Table 2, ash sintered stronger in pressurised conditions than at atmospheric pressure. 

There is a general consensus that analysis of fresh material yields results which come closest to the natural distribution pattern in plants. Since this approach is not feasible in most cases suitable preservation procedures must be employed. Advantages and disadvantages of such procedures with respect to polyphenol analysis have been reviewed by several authors [47-49]. The procedure keeping the chemical composition as close as possible to the natural state is lyophilization. A study of the extractability of proanthocyanidins in the bark of several pines (Pinus sp.) showed no difference between freshly collected samples and freeze-dried samples. On the other hand drying at room temperature resulted in an increase in extractability in one sample [50]. Increased extractability after drying at room temperature compared to fresh material has also been... 

Wood is a complex product of an unstable biological system. Its total chemical composition and the physical-chemical relationships remain to be elucidated. Parts of the tree are normally eaten at some seasons of the year by ruminants and other herbivores. Bark, browse, and leaves are the major items consumed (6, 19, 27, 28, 29). The reported composition of several components are shown in Table I. 

Fraxinus ornus (L.) is a small tree belonging to the Oleaceae family widely found in Bulgaria. Its stem bark is used in the Bulgarian folic medicine for treatment of infected wounds, inflammation, arthritis and dysentery [1,2]. However, the claims of the traditional medicine were not scientifically confirmed, the toxicity of the extract was not examined and the chemical composition of the bark was not completely investigated. 

Our investigations provide more data on the chemical composition and biological properties of Frctxinus ornus and support the claims of the traditional medicine by presenting scientific proofs for the biological activity of the bark extract and its components. 

Essential oils are usually derived from the non-seed parts of the plants with chemical composition other than the triglyceride structure of natural fats and oils. They refer to the subtle, aromatic liquids extracted from the flowers, seeds, leaves, stems, bark and roots of herbs, bushes, shrubs and trees through distillation. Essential oils are concentrated liquids containing volatile aromatic compounds. They are used in perfumery, aromatherapy, cosmetics, incense, medicine, household cleaning products and for flavouring food and drink. Their use in aromatherapy and other health care areas is growing. 

Table 3A.1 Average chemical composition of wood, forest residue,and bark (inner and outer bark) (%of the feedstock dry solids) ...

Simionatto, E., V.F.L. Bonani, A.F. Morel, et al., 2007 Chemical composition and evaluation of antibacterial and antioxidant activities of the essential oil of Croton urucurana BaiUon (Euphorbiaceae) stem bark. J. Braz Chem. Soc., 18(5) 879-885. 

Kamdem, D. P., and D. A. Gage. 1995. Chemical composition of essential oil from the root bark oiSassafras albidum. J. Org. Chem. 61(6) 574—575. 

Holmes G W, Kurth E F 1961 The chemical composition of the newly formed inner bark of Doug-las-fir. Tappi 44 893-898... 

Chang Y-P, Mitchell R L 1955 Chemical composition of common North American pulpwood barks. Tappi 38(5) 315-320... 

Hergert H L 1958 Chemical composition of cork from white fir bark. For Prod J 8 335-339... 

Kurth E F 1967 The chemical composition of conifer bark waxes and corks. Tappi 50(6) 253-258... 

Narasimhachari N, von Rudloff E 1961 The chemical composition of the wood and bark extractives of Juniperus horizontalis Moench. Can J Chem 39 2572-2581... 

Streibl M, Konecny K, Mahdalik 1969 Chemical composition of beech bark. I. Investigation of lipids. Cellul Chem Technol 3 653-656... 

Streibl M, Mahdalik M 1971 Chemical composition of some hydrocarbons of the lipoid fraction from the beech bark. Holzforsch Holzverwert 23 32-35... 

Chabeau E 1938 Chemical composition of the bark of Nemuaron humboldtii. Bull Acad Roy Med Belg 3 46-66... 

Hergert H L 1960 Chemical composition of tannins and polyphenols from conifer wood and bark. Forest Prod J 10 610-617... 

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