Phenylethanoid glycosides as a new macrophage-activating factor

麦角甾苷，苯丙素苷，被发现诱导巨噬细胞或SV 4 O转化的内皮细胞（GEN-T）细胞因子的产生和粘附分子的表达。另一方面，毛蕊花糖苷对多种肿瘤细胞具有细胞毒性。本研究探讨了细胞活化和细胞死亡的信号转导途径是否存在差异。毛蕊花糖苷在加入培养基后1 min即产生过氧化氢，用scopletin法检测到过氧化氢的产生。过氧化氢的产生依赖于类叶升麻苷的量，过氧化氢酶的预处理可以抑制类叶升麻苷的产生。当检查产生的过氧化氢的量和对肿瘤细胞的细胞毒性强度之间的关系时，产生的过氧化氢的量诱导细胞死亡。此外，过氧化氢酶完全抑制毛蕊花糖苷诱导的细胞死亡。与此相反，细胞粘附分子表达的类叶升麻苷对GEN-T细胞不受预处理与过氧化氢酶，这表明过氧化氢没有牵连的信号转导GEN-T细胞活化类叶升麻苷。迄今为止，我们认为活性氧、细胞内钙离子和蛋白质磷酸化是类叶升麻苷引起的信号转导的第二信使，而类叶升麻苷衍生的过氧化氢和过氧化氢介导的磷酸化将被上述事实否定。其确切的信号转导机制尚待进一步阐明。

Acteoside, a phenylpropanoid glycoside, was found to induce cytokine production and adhesion molecule expression on macrophages or SV4O-transformed endothelial cells (GEN-T). On the other hand, acteoside showed cytotoxicity against various kinds of tumor cells. In this study we studied whether the pathway of signal transduction in cell activation and cell death was different or not. Acteoside produced hydrogen peroxide which was detected by scopletin method as early as 1 min after its addition into medium. Its hydrogen peroxide production was dependent on the amount of acteoside and was abolished by the pretreatment with catalase. When the relationship between the amount of produced hydrogen peroxide and the intensity of cytotoxicity against tumor cells was examined, cell death was induced with the amount of produced hydrogen peroxide. In addition catalase completely inhibited acteoside-induced cell death. In contrast, cell adhesion molecule expression on GEN-T cells by acteoside was not influenced by pretreatment with catalase, suggesting that hydrogen peroxide was not implicated in the signal transduction of GEN-T cell activation by acteoside. We so far considered reactive oxygen species, intracellular calcium and protein phosphorylation as second messenger of signal transduction elicited by acteoside, whereas acteoside-derived hydrogen peroxide, and phosphorylation mediated by hydrogen peroxide would be negated by the facts described above. The precise mechanism of signal transduction remains to be clarified in the future.