Extraction of polyflavonoids from Pinus radiata D. Don Bark.: Evaluation of effects of solvent composition and of the height on tree bark

This work evaluates the effect of the composition of the solvent mixture on the extraction of polyflavonoids from the bark of Pinus radiata. Non-reactive solvent systems were selected, specifically water 100%, methanol 100 %, and mixtures of them in proportions (7:3), (1:1) and (3:7). The amounts of the extracted with water were lower than those obtained with methanol mixtures. Large variations were not observed when the proportion of methanol in the solvent changes, however the reactive polyphenol percentage increases as the methanol proportion in the extracting solvent is increased. The effect of the section height of the tree from which the bark is obtained, on the nature of the polyflavonoids extracted with such solvents, has been evaluated. The obtained fractions were characterized by chemical assays, chromatographic (GPC) and spectrophotometric (IR) methods.