Impact of natural ageing of four Guyanese wood residues on the antitermite activity of ethyl acetate extracts

Amazonian wood residues are a source of numerous molecules that can be used in a wide range of applications. Certain molecules exhibit antioxidant, antifungal, and antitermite properties, suggesting their potential use as alternative to petroleum-derived compounds. One interesting application is their incorporation as active ingredients in the formulation of bio-sourced wood preservation treatment. The impact of natural ageing of the residues and storage conditions should be taken into consideration for a potential chemical valorisation, because wood chemical composition can be altered. However, this impact remains poorly documented and understood. Therefore, the present research aims to assess the impact of 4-years difference in natural ageing in indoor conditions of residues from four Guyanese wood species (Basralocus, Louro vermelho, Wallaba, Wacapou). For each wood species, the antitermite activity was evaluated against European subterranean termites ( Reticulitermes flavipes ) by laboratory screening tests. The extract from fibres with the longest storage duration (5-years) fibres showed lower antitermite activity than those from the shortest storage duration (1-year), indicating a loss of efficacy during storage. A literature-based analysis of major metabolites suggests that chemical degradation during ageing may account for this decline. These results highlight the importance of taking ageing and storage conditions into account when considering the chemical valorisation of Amazonian wood residues.