Wood preservative potential of extracts of the leaves of Morinda lucida (Benth.) and Datura stramonium (L.)

Morinda lucida and Datura stramonium are used medicinally for various purposes in Nigeria. Insecticidal activity of the fruit and antimicrobial activities of other parts of M. lucida had been reported. D. stramonium had been reported to be toxic to animals. Ethanol extracts of M. lucida and D. stramonium leaves were partitioned successively into petroleum ether, chloroform, ethyl acetate and methanol fractions. Each fraction was tested as wood preservative in-vivo at three different concentrations: 0.5%, 1.0% and 1.5% w/v. Basudin®, an organophosphate was used as standard. The extracts were applied on Triplochiton schleroxylon, a highly susceptible wood. The treated wood samples were exposed to termites for a period of twelve weeks. Observation was carried out weekly for signs of termite infestation. Weight loss in wood samples that were treated with fractions of D. stramonium extract ranged from 8.20% –13.50% in petroleum ether fraction, 9.35%-19.99% in chloroform fraction, 6.15% and 10.89% in ethyl acetate fraction and 10.81%-20.27% in methanol fraction. Petroleum ether, chloroform, ethyl acetate and methanol soluble fractions of M. lucida gave a weight loss range of 5.25%- 9.50%, 6.28%-11.50%, 4.89%-6.70% and 8.50%-20.27% respectively. Ethyl acetate soluble fractions of the two plants are more potent and that of M. lucida was the most effective in damage reduction. The phytochemical screening, ¹H NMR and ¹³C NMR suggest anthraquinone and scopoletin as the major components of ethyl acetate soluble fraction of M. lucida. This study reveals that anthraquinone and scopoletin are likely to be responsible for for the observed wood preservation.