Accumulated evidence shows that some phytochemicals provide beneficial effects for human health. Recently, a number of mechanistic studies have revealed that direct interactions between phytochemicals and functional proteins play significant roles in exhibiting their bioactivities. However, their binding selectivities to biological molecules are considered to be lower due to their small and simple structures. In this study, we found that zerumbone, a bioactive sesquiterpene, binds to numerous proteins with little selectivity. Similar to heat-denatured proteins, zerumbone-modified proteins were recognized by heat shock protein 90, a constitutive molecular chaperone, leading to heat shock factor 1-dependent heat shock protein induction in hepa1c1c7 mouse hepatoma cells. Furthermore, oral administration of this phytochemical up-regulated heat shock protein expressions in the livers of Sprague-Dawley rats. Interestingly, pretreatment with zerumbone conferred a thermoresistant phenotype to hepa1c1c7 cells as well as to the nematode Caenorhabditis elegans. It is also important to note that several phytochemicals with higher hydrophobicity or electrophilicity, including phenethyl isothiocyanate and curcumin, markedly induced heat shock proteins, whereas most of the tested nutrients did not. These results suggest that non-specific protein modifications by xenobiotic phytochemicals cause mild proteostress, thereby inducing heat shock response and leading to potentiation of protein quality control systems. We considered these bioactivities to be xenohormesis, an adaptation mechanism against xenobiotic chemical stresses. Heat shock response by phytochemicals may be a fundamental mechanism underlying their various bioactivities.

TiO2 films are deposited on glass substrate in O2/Ar gas mixtures by facing target planar magnetron (FT-PM) sputtering, and the effects of the sputtering system on the crystal phases and axis orientation of TiO2 films are investigated for as-deposited films. Deposition is carried out by two systems: In the first system the opposing magnets have opposite polarites of internal permanent magnets in each target holder; this leads to confinement of the electrons therefore weak electron bombardment on the substrate. The result is poor grain growth with low quality anatase films with poor photocatalytic activity. In the second system the opposing magnets have the same polarities each other; the electron bombardment becomes strong and grain growth is enhanced. The results indicate a high quality anatase film with very good photocatalytic activity.