Testing was conducted to determine the effectiveness of hinokitiol against methicillin-resistant Staphylococcus aureus (MRSA), an important cause of hospital-acquired infection. The antibacterial testing, made in accordance with the standard method described by Japan Society of Chemotherapy, showed that hinokitiol has an excellent antibacterial effect above 100μg/ml for both MRSA and methicillin-sensitive S. aureus (MSSA).
   The antibacterial effects of hinokitiol against MRSA appeared to be primarily a denaturalizing effect on the structural protein; however, a triplet ring was generated during testing using the method of the agar disk diffusion susceptibility test, and MRSA showed an increasing potential during the decrease in the active germ in a culture medium exposed to hinokitiol solution. This is supposed to be due to the differences of the antibacterial action under large and small concentrations of hinokitiol in the culture medium. Using a phase-contact microscope, the activity of hinokitiol against the bacteria was observed, and it was determined that Escherichia coli, gram-negative rod, burst and/or solidified, but MRSA, gram-positive cocci, showed no change other than swelling.
   Hinokitiol is unstable under light and oxygen; therefore it is necessary to be stabilized by the formation of metal-hinokitiol chelate compounds to achieve a stable reaction effect. It was found that the antibacterial effect of metal-hinokitiol chelate compounds changes according to the types of metals.

   The contents of hinokitiol in the wood of Thujopsis dolabrata S. and Z. which grew in different areas were investigated. The difluoroborane compound of hinokitiol, which is a kind of chelate produced by the reaction of hinokitiol with boron trifluoride, was applicable to the micro-determination of hinokitiol by HPLC. The contents of hinokitiol were different among growing areas, especially the content of hinokitiol from the heartwood of T. dolabrata which grew in the Kanaki area which was the greatest among all the tested samples.
   The effective extraction procedures for hinokitiol from the wood of T. dolabrata were investigated by comparing hot-water distillation, organic solvent extraction, and supercritical carbon dioxide extraction (SFE). When methanol was used as a solvent, the yield of hinokitiol in the extractives was the greatest; however, the relative yield of hinokitiol with supercritical carbon dioxide extraction was much greater than in the methanol extraction. No effective cosolvent for carbon dioxide for extracting hinokitiol was found with due consideration of the extractive characteristics such as residual toxity and great selectivity for extraction. Supercritical carbon dioxide extraction was considered to be the most effective method for extracting hinokitiol from the wood of T. dolabrata.

   To prevent nosocomial infection, we examined the use of hinokitiol sodium salt when cleaning. In addition to this sodium salt, we used povidoniodo. We found a tendency for the amount of viable methicillin-resistant Staphylococcus aureus (MRSA) decrease as time has passed after temporarily increasing. We examined statistically the bactericidal action by using the floors of general wards with secreting MRSA patients in the entire country in 16 hospitals. We found disinfection to be statistically significant and effective at about 343 places, and effective at the same measurement points in 125 places. In addition, we examined long-term cleaning effects using hinokitiol sodium salt. As a result, we found the number of detected bacteria and the detection rates being improved to 10% or less before using in Hospital N. Moreover, we found after six months a sharp decrease in the number of detected bacteria in three months and an entering state which was almost zero in Hospital K.

   In this review the author examines works on anti-tyrosinase activity of Artocarpus incisus heartwood and on steroid 5&alpha-reductase inhibitory activity of resveratrol oligomers isolated from Shorea spp. heartwood. The contribution of the 2,4-dihydroxyphenyl structure to the anti-tyrosinase activity is noted. Enzymatic dehydrogenative polymerization of resveratrol yielded 5&alpha-reductase inhibitory oligomers that are structurally related to the natural products of Shorea spp. heartwood. In addition, the author examines studies on hinokitiol (β-thujaplicin), a heartwood constituent of Cupressaceae species exhibiting a variety of bioactivities. Emphasis is placed on its production by Cupressus lusitanica cell cultures, on signal transduction after elicitation, and on the biosynthetic pathway. Cyclic AMP, calcium channel activation, and the jasmonate pathway are proposed to be involved in the multiple signal transduction from fungal elicitor action to the commencement of β-thujaplicin production. It has been proven that β-thujaplicin is biosynthesized from geranyl diphosphate that is formed through the recently found methylerythritol phosphate pathway. Terpinolene is proposed as a precursor, which in turn rearranges to give the seven-member ring of β-thujaplicin, though exact mechanism of the rearrangement is still unknown.