Department of Pharmacology, Guangdong Medical College, Zhanjiang, Guangdong, 524023, PR China.
Biochimie. 2012 Dec;94(12):2514-22. doi: 10.1016/j.biochi.2012.06.033. Epub 2012 Jul 11.
Accumulating evidences suggest that Herba epimedii has the potential benefits against osteoporosis. However, previous studies were focused on the crude extract, total flavonoids (TF) and icariin (ICA), and the detailed molecular mechanisms of action and structure-activity relationship (SAR) remain unclear. Herein we aimed to systematically investigate the effects of Herba epimedii flavonoids (HEF) on the activity of osteoclasts, and explore the potential SAR. Both ICA and baohuoside-1 (BS) significantly inhibited the proliferation of RAW 264.7 cells (IC(50) 25 μM and 67 μM, respectively). Treatment of ICA resulted in G2/M arrest and apoptosis in RAW 264.7 cells as early as 12 h. Besides, HEF remarkably suppressed vitamin D-induced differentiation of osteoclasts in rabbit bone marrow cells and the bone resorption of rabbit mature osteoclasts in vitro. It is notable that the inhibitory effect of 100 μM ICA and BS on osteoclast formation is almost 90%; and the inhibition rate on bone resorption is 50% and 80%, respectively. Besides, RANKL-induced osteoclast formation from RAW 264.7 cells and the expression of TRAP, CA II, CTSK and MMP-9 was significantly reduced by the treatment of 25 μM HEF and 17β-estradiol (ES), and the inhibitory strength increases in the order TF < ES < ICA < BS, which was blocked by ICI182780 suggesting that the regulation of osteoclast activity might be ER dependent. Furthermore, the free hydroxyl group at C-7 of BS played an important role in the SAR for anti-osteoclast action. To conclude, HEF could regulate the formation and activity of osteoclasts by inhibiting the proliferation and differentiation, inducing apoptosis and cell cycle arrest and suppressing bone resorption of osteoclasts. Changes in osteoclast activity are probably mediated predominantly by interaction with nuclear estrogen receptors and via mitochondrial pathway. HEF, especially BS, has great potential for the prevention and treatment of osteoporosis.
越来越多的证据表明，淫羊藿具有防治骨质疏松的潜在益处。然而，之前的研究主要集中在淫羊藿粗提物、总黄酮（TF）和淫羊藿苷（ICA）上，其详细的作用机制和构效关系（SAR）尚不清楚。在此，我们旨在系统研究淫羊藿黄酮（HEF）对破骨细胞活性的影响，并探讨其潜在的 SAR。ICA 和宝藿苷-1（BS）均能显著抑制 RAW 264.7 细胞的增殖（IC50 分别为 25 μM 和 67 μM）。ICA 处理可导致 RAW 264.7 细胞在 12 h 时出现 G2/M 期阻滞和凋亡。此外，HEF 能显著抑制维生素 D 诱导的兔骨髓细胞破骨细胞分化和兔成熟破骨细胞体外骨吸收。值得注意的是，100 μM ICA 和 BS 对破骨细胞形成的抑制作用几乎达到 90%；对骨吸收的抑制率分别为 50%和 80%。此外，25 μM HEF 和 17β-雌二醇（ES）能显著抑制 RANKL 诱导的 RAW 264.7 细胞破骨细胞形成以及 TRAP、CA II、CTSK 和 MMP-9 的表达，抑制强度依次为 TF < ES < ICA < BS，该抑制作用可被 ICI182780 阻断，提示对破骨细胞活性的调节可能依赖于 ER。此外，BS 中 C-7 位的游离羟基在抗破骨细胞作用的 SAR 中起着重要作用。综上所述，HEF 可通过抑制增殖和分化、诱导凋亡和细胞周期阻滞以及抑制破骨细胞骨吸收来调节破骨细胞的形成和活性。破骨细胞活性的变化可能主要通过与核雌激素受体相互作用以及通过线粒体途径介导。HEF，特别是 BS，在骨质疏松的防治方面具有巨大潜力。
