Department of Biochemistry, University of Stellenbosch, Stellenbosch 7600, South Africa.
J Steroid Biochem Mol Biol. 2012 Feb;128(3-5):128-38. doi: 10.1016/j.jsbmb.2011.11.003. Epub 2011 Nov 12.
The steroid hormone output of the adrenal gland is crucial in the maintenance of hormonal homeostasis, with hormonal imbalances being associated with numerous clinical conditions which include, amongst others, hypertension, metabolic syndrome, cardiovascular disease, insulin resistance and type 2 diabetes. Aspalathus linearis (Rooibos), which has been reported to aid stress-related symptoms linked to metabolic diseases, contains a wide spectrum of bioactive phenolic compounds of which aspalathin is unique. In this study the inhibitory effects of Rooibos and the dihydrochalcones, aspalathin and nothofagin, were investigated on adrenal steroidogenesis. The activities of both cytochrome P450 17α-hydroxylase/17,20 lyase and cytochrome P450 21-hydroxylase were significantly inhibited in COS-1 cells. In order to study the effect of these compounds in H295R cells, a human adrenal carcinoma cell line, a novel UPLC-MS/MS method was developed for the detection and quantification of twenty-one steroid metabolites using a single chromatographic separation. Under both basal and forskolin-stimulated conditions, the total amount of steroids produced in H295R cells significantly decreased in the presence of Rooibos, aspalathin and nothofagin. Under stimulated conditions, Rooibos decreased the total steroid output 4-fold and resulted in a significant reduction of aldosterone and cortisol precursors. Dehydroepiandrosterone-sulfate levels were unchanged, while the levels of androstenedione (A4) and 11β-hydroxyandrostenedione (11βOH-A4) were inhibited 5.5 and 2.3-fold, respectively. Quantification of 11βOH-A4 showed this metabolite to be a major product of steroidogenesis in H295R cells and we confirm, for the first time, that this steroid metabolite is the product of the hydroxylation of A4 by human cytochrome P450 11β-hydroxylase. Taken together our results demonstrate that Rooibos, aspalathin and nothofagin influence steroid hormone biosynthesis and the flux through the mineralocorticoid, glucocorticoid and androgen pathways, thus possibly contributing to the alleviation of negative effects arising from elevated glucocorticoid levels.
肾上腺的类固醇激素分泌对于维持激素内环境稳定至关重要，激素失衡与许多临床情况有关，包括高血压、代谢综合征、心血管疾病、胰岛素抵抗和 2 型糖尿病等。Aspalathus linearis（南非路易波士茶）已被报道可缓解与代谢疾病相关的应激症状，它含有广泛的生物活性酚类化合物，其中 aspalathin 是独特的。在这项研究中，研究了南非路易波士茶和二氢查尔酮，aspalathin 和 nothofagin，对肾上腺类固醇生成的抑制作用。在 COS-1 细胞中，细胞色素 P450 17α-羟化酶/17,20 裂解酶和细胞色素 P450 21-羟化酶的活性均显著受到抑制。为了研究这些化合物在 H295R 细胞中的作用，H295R 细胞是一种人肾上腺皮质癌细胞系，开发了一种新的 UPLC-MS/MS 方法，用于通过单次色谱分离检测和定量 21 种类固醇代谢物。在基础和 forskolin 刺激条件下，在存在南非路易波士茶、aspalathin 和 nothofagin 的情况下，H295R 细胞中产生的类固醇总量显着减少。在刺激条件下，南非路易波士茶使总类固醇产量减少 4 倍，并导致醛固酮和皮质醇前体的显着减少。脱氢表雄酮硫酸盐水平保持不变，而雄烯二酮（A4）和 11β-羟基雄烯二酮（11βOH-A4）的水平分别抑制了 5.5 倍和 2.3 倍。11βOH-A4 的定量表明，这种代谢物是 H295R 细胞类固醇生成的主要产物，我们首次证实，这种类固醇代谢物是人类细胞色素 P450 11β-羟化酶将 A4 羟化的产物。总之，我们的结果表明，南非路易波士茶、aspalathin 和 nothofagin 影响类固醇激素生物合成和通过盐皮质激素、糖皮质激素和雄激素途径的通量，从而可能有助于缓解由于糖皮质激素水平升高而产生的负面影响。
