Trehalose is known to act as a protectant against various environmental stresses, including drying, freeze, oxidation, ethanol, osmolarity and so on. In this mini review, we discuss such cross protection effect of trehalose together with possible molecular mechanisms. First, the cross protection effect against salt, freeze-dying and ethanol stresses in yeast cells are discussed based on the so-called water replacement mechanism. Second, the desiccation tolerance in larvae of Polypedilum vanderplanki is discussed based on the vitrification mechanism. Third, the antioxidant function of trehalose is discussed based on the interaction model between trehalose and a hydrophobic group, especially cis type C=C bond. Finally, it is suggested that the physicochemical origin of the cross protective function of trehalose is ascribed to the structural peculiarity of this sugar, that is, the presence of α, α-l,1 glycosidic bond.
