The 2,6-di-O-methyl-β-cyclodextrin (dMβCD) is an amphiphilic annular compound consisting of seven dimethylglucose 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 Gramnegative microaerophilic bacillus recognized as a pathogen concerned with gastrointestinal diseases in human.
Previous studies by the 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 review the following interactions between dMβCD, steroidal compounds, and H. pylori myristoyl-phosphatidyl ethanolamine (PE) were described:
(1) dMβCD tightly binds to the myristoyl-PE of H. pylori biomembranes;
(2) dMβCD promotes the absorption of cholesterol into the H. pylori biomembranes;
(3) dMβCD inhibits the absorption of relatively low-molecular-weight steroids into the H. pylori biomembranes;
(4) dMβCD protects H. pylori from the bactericidal action of progesterone and 17α-hydroxyprogesterone caproate;
(5) dMβCD has no effect on the bactericidal action of 17α-hydroxyprogesterone linoleate against H. pylori. However, there are still a number of enigmas as to either how dMβCD delivers the steroidal compounds to the biomembranes of H. pylori or how dMβCD selectively prevents the binding of several steroidal compounds to the biomembranes of H. pylori.
Kiyofumi Wanibuchi, Kouichi Hosoda, Avarzed Amgalanbaatar, Yoshikazu Hirai, Mitsuru Shoji, Hirofumi Shimomura (2021) A short review, effect of dimethyl-β-cyclodextrin on the interaction between Helicobacter pylori and steroidal compounds, Heliyon, 7(4), e06767,