Tropolone derivative found in the heartwood of cupressaceous plants including western red cedar, eastern white cedar, and hiba; β-thujaplicin antimicrobial activity contributes to the decay-resistance of these trees. Isoln from western red cedar, Thuja plicata D. Don: H. Erdtman, J. Gripenberg, Nature 161, 719 (1948); and characterization: A. B. Anderson, J. Gripenberg, Acta Chem. Scand. 2, 644 (1948). Synthesis: W. von E. Doering, L. H. Knox, J. Am. Chem. Soc. 75, 297 (1953). Biosynthesis in Cupressus lusitanica: J. Zhao, K. Sakai, J. Exp. Bot. 54, 647 (2003). HPLC determn in cosmetics: M. Endo et al., J. Chromatogr. 455, 430 (1988). CZE determn in aqueous solns: L. Dyrskov et al., J. Agric. Food Chem. 52, 1452 (2004). Antibacterial activity in atopic dermatitis: Y. Arima et al., J. Antimicrob. Chemother. 51, 113 (2003).