Division of Molecular Oncology and Virology, Medical Research Institute, Kanazawa Medical University, Uchinada, Ishikawa, Japan.
Int J Mol Med. 2010 Dec;26(6):787-93. doi: 10.3892/ijmm_00000526.
Herbal remedies containing root extracts of Panax ginseng are commonly used for complementary or alternative therapies. Ginsenosides, the major components of root extracts, are responsible for ginseng's pharmacological and biological effects; however, their mechanisms of action are unclear. We examined whether membrane cholesterol was involved in the mechanism of action of ginsenoside Rh2 in cultured cells. In B16 melanoma cells, Rh2 (18.5 µM) induced dendrite formation within 2 h. Depletion of cholesterol by pretreatment with 10 mM methyl-β-cyclodextrin suppressed this effect of Rh2. Rh2 did not change the cellular cholesterol content and the immunofluorescence staining pattern of the lipid-raft-associated molecules, ganglioside GM3, Caveolin-1, Flotillin-1, and Flotillin-2, for up to 3 or 6 h. However, within 2 min of addition, Rh2 changed the fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene (DPH) but not of 1-[4-(trimethylammonio)phenyl]-6-phenyl-1,3,5-hexatriene (TMA-DPH). DPH is more sensitive than TMA-DPH to changes in the physical properties of membrane lipid bilayers regulated by cholesterol. These results suggest that Rh2 affects the physical properties of cholesterol-regulated membrane lipid bilayers and could lead to changes in cellular functions.
含有人参根提取物的草药疗法常用于补充或替代疗法。人参皂苷是根提取物的主要成分，负责人参的药理和生物学作用；然而，其作用机制尚不清楚。我们研究了膜胆固醇是否参与了人参皂苷 Rh2 在培养细胞中的作用机制。在 B16 黑色素瘤细胞中，Rh2（18.5 μM）在 2 小时内诱导树突形成。用 10 mM 甲基-β-环糊精预处理以耗尽胆固醇会抑制 Rh2 的这种作用。Rh2 不会改变细胞胆固醇含量和脂质筏相关分子的免疫荧光染色模式，直到 3 或 6 小时。然而，添加后 2 分钟内，Rh2 改变了 1,6-二苯基-1,3,5-己三烯（DPH）的荧光偏振，但不改变 1-[4-（三甲铵基）苯基]-6-苯基-1,3,5-己三烯（TMA-DPH）的荧光偏振。DPH 比 TMA-DPH 对胆固醇调节的膜脂双层物理性质的变化更敏感。这些结果表明，Rh2 影响胆固醇调节的膜脂双层的物理性质，并可能导致细胞功能的变化。
