Institute of Pharmacology, University of Yang Ming, Taipei, Taiwan, ROC.
Phytomedicine. 2010 Jul;17(8-9):626-34. doi: 10.1016/j.phymed.2009.12.007. Epub 2010 Jan 21.
The antidiabetic actions of Paeoniae Radix involve stimulating glucose uptake and reducing glucose absorption. However, the importance of this herb in the transcriptional regulation of hepatic gluconeogenesis has not previously been investigated, although hepatic gluconeogenesis contributes the most to fasting hyperglycemia. Using rats with streptozotocin-induced diabetes and db/db mice, the dose- and time-dependent suppressive effects of the ethanol extract of Paeoniae Radix (PR-Et) on diabetic hyperglycemia and phosphoenopyruvate carboxykinase (PEPCK) transcription are first demonstrated. Second, by employing H4IIE cells, the inhibitory action of PR-Et on both dexamethasone- and 8-bromo-cAMP-induced-PEPCK expression was also confirmed without causing any cytotoxicity. In addition, this inhibitory effect could be sustained for over 24 h with repeated treatment. Most importantly, PR-Et's action was unaffected by either insulin desensitization or palmitate stimulation. Finally, paeonol and paeoniflorin, two well-known constituents in Paeoniae Radix, did not suppress PEPCK expression at testing concentration. In conclusion, it was clearly demonstrated that transcriptional inhibition of gluconeogenesis is one of the important antidiabetic actions of Paeoniae Radix. Future development of this herb as a dietary supplement or drug should bring substantial benefits for the diabetic population.
白芍的降血糖作用涉及刺激葡萄糖摄取和减少葡萄糖吸收。然而，尽管肝糖异生对空腹高血糖的贡献最大，但以前尚未研究过这种草药在肝糖异生转录调控中的重要性。本研究采用链脲佐菌素诱导的糖尿病大鼠和 db/db 小鼠，首次证明了白芍乙醇提取物（PR-Et）对糖尿病高血糖和磷酸烯醇丙酮酸羧激酶（PEPCK）转录的剂量和时间依赖性抑制作用。其次，通过 H4IIE 细胞实验，还证实了 PR-Et 对地塞米松和 8-溴-cAMP 诱导的 PEPCK 表达的抑制作用，且无细胞毒性。此外，这种抑制作用可在重复治疗后持续 24 小时以上。最重要的是，PR-Et 的作用不受胰岛素脱敏或棕榈酸盐刺激的影响。最后，白芍中的两种熟知成分丹皮酚和芍药苷在测试浓度下均不抑制 PEPCK 表达。总之，明确表明，抑制肝糖异生的转录是白芍的重要降血糖作用之一。将这种草药作为膳食补充剂或药物进一步开发，将为糖尿病患者带来实质性的益处。
