The 2,6-di-O-methyl-β-cyclodextrin (dMβCD) is an amphiphilic annular compound consisting of seven dimethyl-glucose molecules. This compound is well known as a solubilizer of lipophilic compounds. Especially, dMβCD extracts cholesterol from the plasma membrane of mammalian cells and releases the cholesterol to the aqueous solution. The experimental use of dMβCD, therefore, serves to investigate the role of cholesterol in the mammalian cell membrane. It is, however, unclear as to how dMβCD extracts cholesterol incorporated into the glycerophospholipid biomembrane. Meanwhile, dMβCD acts as a beneficial compound for Helicobacter pylori and is used as the standard component for supporting the growth of this bacterium in the serum-free culture. However, the detailed mechanism of dMβCD for supporting the growth of H. pylori is still to be clarified. H. pylori is a Gram-negative microaerophilic bacillus recognized as a pathogen concerned with gastrointestinal diseases in human. Previous studies by our group have successfully obtained the H. pylori strains culturable without dMβCD and demonstrated the distinct effects of dMβCD on the interaction between H. pylori and exogenous steroidal compounds. For instance, dMβCD promotes and inhibits the absorption of cholesterol and several steroidal compounds respectively into the biomembranes of H. pylori. In this study we summarized behaviors of dMβCD toward steroidal compounds relevant to H. pylori.
