Some extractives from black spruce (Picea Mariana) bark

Hiscock, Vernon W. (1956) Some extractives from black spruce (Picea Mariana) bark. Masters thesis, Memorial University of Newfoundland.

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Abstract

Bark is a great waste product and comparatively little work has been done to investigate the constituents of the different varieties of it. A review of the components reportedly found in various barks shows that there are four main classes. These are cellulose, cork, lignin, and minor constituents. These minor chemicals are reported and a short review of the utilization of waste bark is Included. Minor chemicals include fats, waxes, fatty acids, alcohols, sterols, resin acids, phlobaphenes, and polysaccharides. -- Minor chemicals found in black spruce wood are reported and a section is devoted to methods that have been used for extraction of minor chemicals from barks. Many workers have begun extraction with alcohol but since this solvent extracts, among other things, tannins, petroleum ether was used first, followed by diethyl ether. -- The petroleum ether extract has been found to contain steroid type compounds. The crude extract could not be further separated easily using solvents, so chromatography was used. This is an excellent method for separating substances of closely related structure. A volatile oil as well as the steroids is reported. -- The Ether extract was found to contain flavone type ccmpounds, one of which is Quercetin (3, 5, 7, 3’ 4’, -pentahydroxyflavone). This appears as a glycoside which acetylates quite readily to produce the penta-acetate. Quercetin and its methoxy derivative (3, 5, 7, 3’, 4’, -pentamethoxyflavone) were prepared. -- Paper chromatography and spectrographic analysis were used to identify the quercetin compounds. -- The petroleum ether extract is 5.6% of the weight of the dry bark, and the ether extract about 4%. Difficulty was experienced in attempting to obtain, by crystallization, pure substances. It was found almost impossible to reproduce, exactly, results of any one run. This is because the whole bark was extracted and also because some changes occur in the bark during storage.

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