Evaluation of Bio-preservative Potential of Parquetina nigrescens Leaf Extract against Wood Decay Fungi

The restriction on the use of conventional wood preservative necessitated the search for eco-friendly wood preservative against biodeteriorating agents. The study was carried out to evaluate the biopreservative potential of Parquetina nigrescens against fungi attack on Triplochiton scleroxylon wood. Ethanol was used as the solvent to get the extract from P. nigrescens leaves after which five different concentration levels (100%, 75%, 50%, 25%, 0%) were prepared. Phytochemical screening of the crude extract was done qualitatively. Forty-eight wood blocks, (each 20 mm x 20 mm x 60 mm) obtained from a 22-year-old Triplochiton scleroxylon were conditioned and treated with the extract using dipping method and the untreated samples served as the control. The wood blocks were inoculated with Pleurotus saju caju (brown rot fungi) and Pleurotus florida (white rot fungi) for 14weeks. Absorption of P. nigrescens leaf extract by wood blocks was determined for all the concentration levels and the resistance of the wood against fungal decay was evaluated using weight loss. Data obtained as analysed using Analysis of variance at p≤0.05. Phytochemical screening of the oil indicated the presence of alkaloids, phenols, terpenoids, tannins, saponins and flavonoids. The absorption of the preservative by the wood ranged between 11.15-110.29 kgm-3 and weight loss ranged between 3.68-36.22 % and 4.31-38.26 % for white rot and brown rot respectively. The different preservative concentration levels significantly influenced the weight loss of the wood species used in this study.