ANALYSIS OF ISOPIMARIC ACID IN TIMBER WOOD USING HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC) AND GAS CHROMATOGRAPHY-MASS SPECTROSCOPY(GC-MS) ( EDUCATION PROJECT TOPICS AND MATERIALS)
CHAPTER ONE
1.0 INTRODUCTION AND LITERATURE REVIEW
1.1: INTRODUCTION
Wood dust is known to be a human carcinogen, based on sufficient evidence of carcinogenicity from studies in humans. It has been demonstrated through human epidemiologic studies that exposure to wood dust increases the occurrence of cancer of the nose (nasal cavities and par nasal sinuses).
Tannins, terpenes and other compounds are the fillers in woody tissue making it a complex substance (Rogge et al., 1998). Many softwood species (gymnosperms) are prolific resin producers. The softwood genera, including pines (Pinus), spruces (Picea), larches (Larix), and firs (Pseudotsuga), have well-established systems of horizontal and vertical ducts filled with resin (Parham and Gray, 1984).
The moisture content of wood varies considerably and the optimal content in terms of minimizing particulate emissions during wood combustion is between 20% and 30% (Core et al., 1982). If the moisture content is too high, an appreciable amount of energy is necessary to vaporize the water, reducing the heating value of the wood as well as decreasing combustion efficiency, which in turn increases smoke formation (Core et al., 1982).
Resin acids and lignans are therefore of interest due to their biological activity (Core et al., 1982). Their composition, distribution and roles were discussed quite early . Lignans (0.4-3 % w/w) have been reported in pine knots, while no detectable amounts were found in the stemwood. As for resin acids, the knots contained large amounts (4.5-30 % w/w) and the stemwood minor amounts.
Lignans are found in large amounts (6-24% w/w), in Finnish spruce knots; with hydroxymatairesinol (HMR, Scheme 1) comprising 65-85% of these lignans. HMR has three chiral centers and occurs as two natural diastereomers. The major diasteromer has been proven to be the 7S,8R,8’R isomer, while the minor isomer, allo-hydroxymatairesinol, has the 7R,8R,8’R configuration. In recent years hydroxymatairesinol has been used as a chiral source in the synthesis of derivatives with bioactive effects. Sapwood tissue contains negligible amount of lignans. In general, only minor amounts of resin acids (< 2/< 0.5 % w/w in stemwood/knots) have been detected in spruce samples (Craedy, 2007). No lignans have been found in Salic caprea (Krat, 2004) and minor amounts of lignan glycosides have been isolated from the inner bark of Betula pendula (Bresy, 2005). A lignan has been isolated from Juniperus communis berries. However, the wood has not been analysed.
