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 timber species 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 that cause wood deterioration. For this, Teak heartwood was obtained, then fragmented and pulverized until obtaining a flour which was used for compounds extraction using the Soxhlet technique coupled to a rotary evaporator through solvents of increasing polarity (hexane, dichloromethane, tetrahydrofuran, and acetone). The extracts obtained were tested against fungal organisms collected in the field, and the LC 50 was determined using teak crude extracts on Artemia salina as a biological model. The results obtained showed that a high flour yield was obtained with hexane (0.951 g), followed by tetrahydrofuran (0.446 g), dichloromethane (0.348 g), and acetone (0.152 g). By using nine fungal organisms that predominantly correspond to the genus Aspergillus, the extractable compounds were 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 LC 50 of 84.9 μg/mL with hexane, 43.3 μg/mL with 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 antimicrobial activity when extracted through polar compounds such as dichloromethane and tetrahydrofuran.

Wood is a lignocellulosic material that, because of its organic nature, is a source of nutrients for bacteria, fungi, and insects. Incisitermes marginipennis (Latreille) is an interesting dry wood-boring termite. Because it is an extremely destructive pest, difficult to control due to its cryptic lifestyle, and for its role in the biogeochemical cycle of carbon and other elements; it is a fundamental organism. The use of less toxic and eco-friendly substances is important for protecting domestic, cultural, and historical heritage made of wood or lignocellulosic materials. The aim of this study was to evaluate the biological activity of various naphthoquinones extracted from the heartwood of T. grandis on I. marginipennis. First, heartwood flour was used for Soxhlet-type extractions to isolate and characterize the heartwood compounds by thin-layer chromatography. To identify the heartwood compounds, nuclear magnetic resonance and gas chromatography coupled to a mass spectrometer were used. The information obtained was supported using the Interactive Spectroscopy software. The identified heartwood compounds were lapachol, tectoquinone, deoxylapachol, dehydro-α-lapachone, tectol and tecomaquinone-I. Using nymphal termites of I. marginipennis as a biological model, the isolated and identified molecules were under three different tests (repellent, insecticide and protective) and their biological activity was individually evaluated. The results showed that the molecules obtained have a repellent-protective effect against I. marginipennis, although not in all cases, these molecules have high percentages of mortality and decreased the weight loss of the treated material exposed to I. marginipennis.