One Step Regioselective Acylation of Polyphenolic Wood Extractive and Its Application for Wood Treatment

This study evaluated the methods of grafting commercial catechin with fatty acids,namely capric acid(C10),lauric acid(C12),and myristic acid(C14)through esterification.Specimens of beech wood(Fagus sylvatica L.)were impregnated with catechin and modified catechin-fatty acids,separately,at a 5%concentration diluted in ethanol using vacuum pressure treatment and subjected to leaching.The weight percentage gain before leaching(WPG),after leaching(WPGAL),and weight loss due to leaching(PL)were investigated.Both leached and unleached samples were tested against white-rot fungi(Trametes versicolor)in Petri-dishes for twelve weeks.Results show that samples treated with modified catechin-fatty acids provide improved resistance towards leaching.Catechin-C14 was found to be more promising,possibly due to its chain length.The decay weight loss for samples treated with modified catechin-fatty acids does not differ significantly between the samples that leached and not.Despite the antifungal properties of catechin,the treatment with catechin alone was insufficient to protect wood samples from fungi.Further,it is recommended to increase the concentration level of modified catechin to obtain a significant effect on the decay resistance.

Antifungal Activity of Crude Extracts of Tectona grandis L.f. against Wood DecayFungi

Wood is mainly made up of cellulose, hemicelluloses, lignin polymers and other organic and inorganic substances, making it susceptible to deteriorate by various biological agents. Tectona grandis L.f. (Teak) is a timberspecies with high resistance to biological deterioration, valued for its durability, beauty, and mechanical resistance.The purpose of this work was to evaluate the antifungal activity of crude extracts from teak on various fungi thatcause wood deterioration. For this, Teak heartwood was obtained, then fragmented and pulverized until obtaininga flour which was used for compounds extraction using the Soxhlet technique coupled to a rotary evaporatorthrough solvents of increasing polarity (hexane, dichloromethane, tetrahydrofuran, and acetone). The extractsobtained were tested against fungal organisms collected in the field, and the LC50 was determined using teak crudeextracts on Artemia salina as a biological model. The results obtained showed that a high flour yield was obtainedwith hexane (0.951 g), followed by tetrahydrofuran (0.446 g), dichloromethane (0.348 g), and acetone (0.152 g). Byusing nine fungal organisms that predominantly correspond to the genus Aspergillus, the extractable compoundswere tested, inhibiting 25% of mycelial growth with tetrahydrofuran (T. versicolor), and 40.9% with dichloromethane(G. trabeum). Likewise, the biological model of A. salina showed an LC50 of 84.9 μg/mL with hexane, 43.3 μg/mLwith dichloromethane, 59.6 μg/mL with tetrahydrofuran, and 54.7 μg/mL with acetone. For this reason, it is concluded that Teak wood contains many extractable compounds in relation to its weight, besides having antimicrobialactivity when extracted through polar compounds such as dichloromethane and tetrahydrofuran.