Resistance of fungal growth on Scots pine treated with caffeine

Alkaloids like caffeine are well-known compounds of natural origin, economically suitable and commercial available, which could facilitate their future use for wood protection. The aim of our study was to determine the resistance of Scots pine (Pinus sylvestris L.) treated with various concentrations of caffeine water solutions (25-0.4 mg mL−1) against common mold fungi and four wood-decaying fungi (Coniophora puteana, Poria placenta, Gloeophyllum trabeum, and Trametes versicolor). Half of the treated specimens before fungal exposition were subjected to leaching procedure. Mass loss from brown rotting fungi was significantly inhibited by all preparations. Moreover, caffeine imparted high resistance in Scots pine to the white-rot fungus T. versicolor. In this study we have shown that to effectively protect wood against all tested decay fungi the concentration of the caffeine solution should be 10 mg mL−1. Complete inhibition of the growth of Aspergillus niger, A. terreus, Chaetomium globosum, Cladosporium herbarum, Paecilomyces variotii, Penicillium cyclopium, P. funiculosum, Trichoderma viride, except A. versicolor and Phoma violacea has been achieved by applying a higher concentration of 25 mg mL−1 of caffeine. Mold and decay resistance of wood treated caffeine is probably related to fact that caffeine has been shown to inhibit chitinases activity, which results in inhibition of fungal growth.