Phenolic extractives of wound-associated wood of beech and their fungicidal effect

Abstract: Extracts of wound-associated beech wood (Fagus sylvatica L.) were spectrophotometrically analyzed and a paper disc screening test was applied to estimate their fungicidal potential against selected brown (Gloeophyllum trabeum) and white (Trametes versicolor) rot fungi. Colorimetric analysis revealed that higher amounts of total phenols, flavonoids and proanthocyanidins were characteristic of the reaction zone, and especially of wound-wood, while the lowest contents were measured in red heart samples. Estimation of the fungicidal properties of wound-associated wood extracts revealed that the evident inhibitory effect on wood decaying fungi can be ascribed to methanolic extracts of wound-wood, as well as to healthy sapwood. Extracts of reaction zones did not exhibit a corresponding inhibitory effect toward the chosen fungi. These results indicate a potential defensive function of wound-wood and sapwood in living trees, whereas already formed reaction zones behave as physical barriers rather than chemically inhibiting fungal growth. [Copyright &y& Elsevier]