Effect of Bark Extract of <em>Erythrophleum Suaveolens (Guillemin & Perrottet) Brenan</em> on Fungal Activities in Wood of <em>Triplochiton Scleroxylon K. Schum</em>

Abstract

The use of traditional biocides such as Chromated Copper Arsenate CCA is being discouraged because of their negative effects on the environment. Extracts from natural products like wood is known to have materials which are capable of reducing activities of wood degrading agents. This study was therefore conducted to investigate the potentials of bark extract of Erythrophleum suaveolens against Ganoderma lucidum, white-rot and Fomitopsis pinicola, brown-rot. Extracts of E.suaveolens bark was obtained using Chloroform-methanol. Wood blocks of Triplochiton scleroxylon sampled from base, middle and top of trees were treated with 5%, 10%, 20% concentrations of the extract as well as 100% water extraction and exposed to white rot and brown rot for 6 weeks. Significant differences were found in level of absorption among sampling positions and concentration levels. Significant differences were observed on the effect of the fungi types, suggesting that the two test fungi have no similar deteriorating mechanism. Bark extract of E. suaveolens at concentration levels of 5%, 10% and 20% of methanol-chloroform extract were effective in suppressing the attack of the two fungi while improve the colour quality of the test wood from white to a more desirable brown. The weight losses of control test blocks were remarkably higher after 6 weeks of fungi exposure with Fomitopsis pinicola (brown-rot) having higher degrading mechanism over Ganoderma lucidum (white-rot) at all concentration levels. One hundred percent (100%) water concentration was the most effective in suppressing the activities of the test fungi. Active biocides identified include alkaloids, cardenolides, antraquinones, saponins and tannins. The result presents cheap, viable and environment friendly alternative to synthetic chemical preservatives and represents a significant advance that addresses both environmental and health concerns associated with wood preservation.