el Izzi A, Benie T, Thieulant M L, Le Men-Olivier L, Duval J
Laboratoire d'Endocrinologie Moléculaire, U.R.A. C.N.R.S. 256, Rennes, France.
Planta Med. 1992 Jun;58(3):229-33. doi: 10.1055/s-2006-961441.
Aqueous extracts from stem bark of Petersianthus macrocarpus contain substances exhibiting both estrogenic and antiestrogenic potency. Triterpenic saponins were identified and extracted as a bulk. Their action on the in vitro LH released by cultured rat pituitary cells was investigated. P. macrocarpus saponins stimulated the LH release in a dose-dependent manner (from 10 micrograms/ml to 300 micrograms/ml). When added simultaneously, saponins and LHRH exerted initial additive effects on LH release, demonstrating independent mechanisms of stimulation. If cells were pre-treated with saponins for 15 min, the amount of LH released under a subsequent LHRH stimulation was lowered, presumably due to a partial depletion of the cells in hormone (data not presented). However, the action of saponins on LH release did not appear specific since a general permeabilizing effect of the cell membrane was evidenced both by trypan blue exclusion and by analysis of the total protein output. When using low concentrations of saponins (10 micrograms/ml), scanning electron microscopy did not reveal any significant alteration of the cell structure, which explains why the cells remain responsive to LHRH after withdrawal of saponins. With higher concentrations (greater than 30 micrograms/ml), the same analytical studies evidenced numerous perforations of the cell membrane, with subsequent cell death. Two highly purified saponin species were tested on LH release by cultured cells; one of them (petersaponin I) appeared responsible for the observed biological effects in vitro. But as cells were shown to be efficiently protected from saponin effects by the presence of serum, it may be concluded that saponins of P. macrocarpus extracts are probably not candidate molecules promoting the in vivo estrogenic and antiestrogenic effects.
大果柯茎皮水提取物含有兼具雌激素活性和抗雌激素活性的物质。已鉴定并大量提取了三萜皂苷。研究了它们对培养的大鼠垂体细胞释放促黄体生成素（LH）的体外作用。大果柯皂苷以剂量依赖方式刺激LH释放（从10微克/毫升至300微克/毫升）。当同时添加时，皂苷和促性腺激素释放激素（LHRH）对LH释放产生初始相加作用，表明存在独立的刺激机制。如果细胞先用皂苷预处理15分钟，随后在LHRH刺激下释放的LH量会降低，推测是由于细胞内激素部分耗竭（数据未列出）。然而，皂苷对LH释放的作用似乎不具有特异性，因为台盼蓝排斥试验和总蛋白输出分析均证明细胞膜存在普遍的通透化效应。使用低浓度皂苷（10微克/毫升）时，扫描电子显微镜未发现细胞结构有任何显著改变，这解释了在撤除皂苷后细胞仍对LHRH有反应的原因。使用较高浓度（大于30微克/毫升）时，同样的分析研究证明细胞膜有大量穿孔，随后细胞死亡。对两种高度纯化的皂苷种类进行了培养细胞LH释放试验；其中一种（大果柯皂苷I）似乎是体外观察到的生物学效应的原因。但由于血清的存在可有效保护细胞免受皂苷影响，因此可以得出结论，大果柯提取物中的皂苷可能不是促进体内雌激素和抗雌激素作用的候选分子。
