Apoptosis-like (possible quantum thermodynamic) cell death induced by Yoshixol and wood oil of Chamaecyparis obtusa (Kiso-Hinoki) on HeLa cell.

1. We report on the cytotoxic effects of neutral wood oil extracted from Chamaecyparis obtusa (Kiso-Hinoki) and of the newly synthetized substance Yoshixol (4,4-dimethyl-6-methylene-2-cyclohexen-1-one) on cultured HeLa cells. 2. The neutral wood oil produced cell death, led to the formation of granules, which were connected with fibrous networks, and reduced cell size. 3. Yoshixol caused a separation of cells, granulation, formation of high-density materials (probably apoptotic body), and reduction of cell size. 4. DNA fragmentation on the electrophoresis was observed with Yoshixol. A low-molecular-weight smear band appeared in the supernatant after treatment with the neutral wood oil. Neither treatment showed higher lactate dehydrogenase (LDH) activity in the culture medium than seen with ethanol as a control. 5. These findings suggest that both the neutral wood oil and Yoshixol have a similar cytotoxic mechanism, reducing cell size and producing a granulation (fragmentation) of eukaryotic cells. 6. Yoshixol may be a potent antitumor agent that induces apoptotic-like cell death. This possible mechanism is discussed.