Turina A del V, Nolan M V, Zygadlo J A, Perillo M A
Biofísica-Química, Departamento de Química, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de Córdoba, Av. Vélez Sarsfield 1611, 5016 Córdoba, Argentina.
Biophys Chem. 2006 Jul 20;122(2):101-13. doi: 10.1016/j.bpc.2006.02.007. Epub 2006 Mar 6.
Monoterpenes (MTs) are highly hydrophobic substances present in essential oils. They cover a wide spectrum of biological effects with a membrane interaction as a common point. Here we studied the surface activity of camphor, cineole, thymol, menthol and geraniol, and their ability to reach and incorporate into model membranes affecting some features of their dynamic organization. All the MTs studied self-aggregated in water with critical micellar concentrations (CMC) between 3 and 8 microM. Their octanol-water and membrane-water partition coefficients were correlated with one another. They all penetrated in monomolecular layers of dipalmitoyl-phosphatildylcholine at the air-water interface, even at surface pressures (pi) above the equilibrium lateral pressure of bilayers; thymol exhibited the highest (61.3 mN/m) and camphor the lowest (37 mN/m) pi(cut-off) value. They affected the self-aggregation of Triton X-100, increasing its CMC from 0.16 mM in the absence of MTs up to 0.68 mM (e.g. for geraniol), and the topology of sPC vesicles, increasing its surface curvature, suggesting their location at the polar head group region of the membrane. The latter was supported by their ability to increase differentially the polarity of the membrane environment sensed by two electrochromic dyes. Dipole moment values (between 1.224 and 2.523 D) and solvation areas (between 80 and 97 A(2)) were calculated from their energy-minimized structures. The relative contribution of each experimental, theoretical and structural property to determine MTs' effects on membrane dynamics were evaluated by a principal component analysis.
单萜类化合物（MTs）是存在于香精油中的高度疏水物质。它们具有广泛的生物学效应，以膜相互作用为共同点。在此，我们研究了樟脑、桉叶油素、百里酚、薄荷醇和香叶醇的表面活性，以及它们到达并融入模型膜中从而影响其动态组织某些特征的能力。所有研究的MTs在水中自聚集，临界胶束浓度（CMC）在3至8微摩尔之间。它们的正辛醇 - 水和膜 - 水分配系数相互关联。它们都能穿透空气 - 水界面处的二棕榈酰磷脂酰胆碱单分子层，即使在高于双层膜平衡侧向压力的表面压力（π）下也是如此；百里酚表现出最高的π（截止）值（61.3毫牛/米），樟脑则最低（37毫牛/米）。它们影响了Triton X - 100的自聚集，使其CMC从无MTs时的0.16毫摩尔增加到0.68毫摩尔（例如香叶醇的情况），并影响了大豆卵磷脂（sPC）囊泡的拓扑结构，增加了其表面曲率，表明它们位于膜的极性头部基团区域。这一点得到了它们能够不同程度地增加两种电致变色染料所感知的膜环境极性的能力的支持。根据它们的能量最小化结构计算出偶极矩值（在1.224至2.523德拜之间）和溶剂化面积（在80至97埃²之间）。通过主成分分析评估了每个实验、理论和结构性质对确定MTs对膜动力学影响的相对贡献。
