Relationship of Tectoquinone to Durability in Tectona grandis

THE heartwood of teak ( Tectona grandis L.f.) is extremely resistant to attack by insects or by fungi; but the reasons for this resistance are not known. It is usually ascribed to the presence of toxic substances, and it has been suggested that tectoquinone (β-methyl anthraquinone), which is characteristically present in teak heartwood, may be responsible. Wolcott 1 has shown this substance to be highly repellent to the dry-wood termite Cryptotermes brevis (Walker), and Sandermann and Dietrichs 2 have demonstrated its toxicity, in high concentrations, to the North American subterranean termite Reticulitermes flavipes Kol. No reference seems to have been made to its toxicity to fungi. In current investigations into the chemical basis of the durability of teak, we have examined the amount of tectoquinone in teak from Thailand and Indonesia, and its toxicity to decay fungi and to subterranean termites.