Potenzy of Azadirachta indica heart wood extracts as wood bio-preservative against termite attack
L O Aguda, O B Olajide, O Y Aguda
Extractives in wood are one of the main reasons for wood resistance against bio-degradation. The chemical compositions of extractives from matured Azadirachta indica that are known to be very resistant against bio-degradation were studied to assess their role as wood preservative. Ethanol and toluene were used in the extraction of these compounds from the heartwood of Azadirahcta indica. Chemical analysis of the extracts was done using Gas Chromatography-Mass Spectrometry (GC-MS) after derivatization using N,O bis (trimethyl silyl) acetamide. The main groups of compounds identified from both extracts are fatty acids, hydrocarbons, sterols, sterol ketones, phenolics, sterol esters and waxes. The extracts obtained were used to treat sapwood of four different wood species that are known to be susceptible to bio-degradation at 12% (weight/weight) retention level. Treated samples were taken to timber graveyard for 12 months. It was observed that the extracts from Azadirachta indica used improved the resistance of these susceptible wood species to termite attack at the timber graveyard more than 70% when compared to the controls and also it was observed that removal of extractives from Azadirahcta indica significantly decreased their resistance to termite attack.
Conclusively, the extractives from Azadirachta indica wood contribute greatly to the protection of susceptible wood species against termite attack.