Investigation of interfacial behavior of glycyrrhizin with a lipid raft model via a Langmuir monolayer study

Seiichi Sakamoto, Hiromichi Nakahara, Takuhiro Uto, Yukihiro Shoyama, Osamu Shibata

研究成果: ジャーナルへの寄稿学術誌査読

29 被引用数 (Scopus)


An interaction of glycyrrhizin (GC) with a lipid raft biomembrane model that consisted of N-palmitoyl-d-erythro-sphingosylphosphorylcholine (PSM), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), and cholesterol (CHOL) was systematically studied using the Langmuir monolayer technique. To construct the lipid raft model, the surface pressure (π)-molecular area (A) and surface potential (ΔV)-A isotherms for three-component (PSM/DOPC/CHOL) systems on 0.02 M Tris buffer with 0.13 M NaCl (pH 7.4) were primarily measured by changing their compositions. Thermodynamic and interaction parameters for binary PSM/DOPC and PSM/CHOL systems revealed that PSM interacts more strongly with CHOL than with DOPC. In addition, a morphological analysis performed with Brewster angle microscopy (BAM) and fluorescence microscopy (FM) revealed an optimal ratio of PSM/DOPC/CHOL (1/1/1, by mole) as a model of lipid rafts. Second, the interaction of GC with the ternary PSM/DOPC/CHOL monolayers was investigated on Tris buffer solutions containing different GC concentrations (1, 5, 10, 25, and 50 μM). In BAM and FM images, microdomains were found to become smaller by increasing the GC concentration in the subphase, suggesting that GC regulates the size of raft domains, which provide dynamic scaffolding for numerous cellular processes. More interestingly, the distinctive GC striped regions were formed at the interface at 50 μM, which shows that GC divides the ternary monolayer into pieces. This phenomenon was observed only in the presence of CHOL in the monolayer. These results suggest that CHOL plays an essential role in the interaction with GC, which results in one of the major activities associated with saponins' membrane disruption.

ジャーナルBiochimica et Biophysica Acta - Biomembranes
出版ステータス出版済み - 4月 2013

!!!All Science Journal Classification (ASJC) codes

  • 生物理学
  • 生化学
  • 細胞生物学


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