Biological Activities in Sapwood and Heartwood Extractives from <i>Paulownia tomentosa</i>

Paulownia tomentosa is a representative deciduous tree in South Korea. After 10 years of growth, its wood can be used to make various products through chemical modifications, such as impregnation with a polymer, substitution with chemicals, and physical compression. However, research on the biological resistance of the sapwood and heartwood parts of P. tomentosa xylem is lacking. To ensure the complete utilisation of Paulownia wood, this study aimed to collect baseline data on the necessity of xylem extraction before chemical modification to enhance wood porosity. First, we assessed the decay and termite resistance of sapwood and heartwood blocks. Furthermore, we evaluated the anti-microbial effect of sapwood and heartwood extracts after solvent fractionation. Quantitative and qualitative analyses of the active substances of the fractions with anti-microbial activity were also conducted. The hexane and chloroform solvent fractions of sapwood and heartwood extracts showed fungal resistance against Trametes versicolor and Fomiptosis palustis. Paulownin and sesamin were the main compounds showing anti-microbial activity, and their content in the extracts varied, depending on the wood part. These results provide valuable data for advancing research on porous wood materials and the utilisation of xylem-derived active compounds from Paulownia wood