On the reasons of Prunus africana natural durability
IRG/WP 07-10611
F Mburu, S Dumarçay, M F Thévenon, P Gérardin
Analysis of Prunus africana heartwood extractives was studied with the aim of understanding the reasons for its high natural durability. Soxhlet extractions of wood powder using different solvents were carried out. Effect of each extracts at different concentrations was evaluated on the growth of several fungi among which Coriolus versicolor, Poria placenta, and Aureobasidium pullulans. Results showed high inhibition rate against all tested fungi. Growth inhibition was particularly important in the case of dichloromethane extracts, which were active even at low concentration. Impregnation of dichloromethane extracts in beech wood inhibited totally wood degradation caused by Coriolus versicolor. Soxhlet extraction of wood blocks was also carried out and the wood blocks tested against termites. Extracted wood blocks showed lower resistance against termites while the unextracted ones were resistant. Evaluation of antitermitic activity on filter paper using the no choice method indicates, however, poor termicidal of the dichloromethane extracts. 1H NMR analysis of the products present in the dichloromethane extract indicates the presence of important quantity of phytosterols, among which oleanolic and ursolic acid, believed to be at the origin of the natural durability of Prunus africana.