Faculty of Pharmaceutical Sciences, Toho University, Miyama 2-2-1, Funabashi, Chiba 274-8510, Japan.
BMC Complement Altern Med. 2014 Feb 20;14:64. doi: 10.1186/1472-6882-14-64.
Protein tyrosine phosphatase (PTP) 1B, a negative regulator of the insulin and leptin signaling pathways, is currently considered a promising target for the development of novel therapeutic approaches used to treat insulin-resistant type 2 diabetes mellitus (IR-T2DM). In this study, we examined the PTP1B inhibitory activity of 147 Japanese prescription Kampo formulations to evaluate their potential for clinical application in IR-T2DM treatment.
We specifically defined the prescribed daily dose as 1 Unit (U), and 147 Japanese prescription Kampo formulations were screened for PTP1B inhibitory activity at a final concentration of 0.1 mU/mL. We investigated the dependence of the inhibitory activity on the concentration of the Kampo formulations that exhibited high PTP1B inhibitory activity. Their inhibition mode by kinetic analysis, inhibitory selectivities against four homologous PTPs (TCPTP, VHR, SHP-1 and SHP-2) and cellular activity in the insulin-signaling pathway by increasing the insulin-stimulated Akt phosphorylation level in human hepatocellular liver carcinoma HepG2 cells, were also investigated. The statistical partial least squares regression method was used to identify the crude drugs with the greatest contribution to the PTP1B inhibitory activity of the Kampo formulations.
Daiokanzoto, Masiningan, Tokakujokito, Keimakakuhanto and Choijokito exhibited high PTP1B inhibitory activity, which was concentration-dependent. Daiokanzoto, Masiningan and Tokakujokito inhibited PTP1B by mixed inhibition modes and exhibited different inhibitory selectivities against four homologous PTPs. Masiningan also exhibited cellular activity. Statistical analyses indicated that the constituent crude drug Rhei Rhizoma provided the greatest contribution to the PTP1B inhibitory activity of these Kampo formulations.
High PTP1B inhibitory activity was predominantly associated with formulations that were classified as Jyokito in Kampo medicine and with a modern clinical indication of constipation. Currently, there is no clinical treatment for IR-T2DM that uses a mechanism of action based on PTP1B inhibition. Thus, we propose the Kampo formulations identified in this study as strong PTP1B inhibitors, which could be developed as clinical therapeutic agents to treat IR-T2DM.
蛋白酪氨酸磷酸酶（PTP）1B 是胰岛素和瘦素信号通路的负调节剂，目前被认为是开发用于治疗胰岛素抵抗型 2 型糖尿病（IR-T2DM）的新型治疗方法的有前途的靶点。在这项研究中，我们检查了 147 种日本处方汉方药对 PTP1B 的抑制活性，以评估它们在 IR-T2DM 治疗中的临床应用潜力。
我们将规定的每日剂量定义为 1 单位（U），并以 0.1 mU/mL 的终浓度筛选 147 种日本处方汉方药对 PTP1B 的抑制活性。我们研究了表现出高 PTP1B 抑制活性的汉方药浓度依赖性抑制活性。通过增加人肝癌 HepG2 细胞中胰岛素刺激的 Akt 磷酸化水平，还研究了它们对四种同源 PTP（TCPTP、VHR、SHP-1 和 SHP-2）的抑制模式和对胰岛素信号通路的细胞活性。使用统计偏最小二乘回归方法确定对汉方药 PTP1B 抑制活性贡献最大的粗药。
大塚万应膏、麻杏薏甘汤、得金散、健胃汤和除脂汤表现出高 PTP1B 抑制活性，且呈浓度依赖性。大塚万应膏、麻杏薏甘汤和得金散通过混合抑制模式抑制 PTP1B，并对四种同源 PTP 表现出不同的抑制选择性。麻杏薏甘汤也具有细胞活性。统计分析表明，这些汉方药中所含的生地黄对 PTP1B 抑制活性的贡献最大。
高 PTP1B 抑制活性主要与被归类为汉方药的 Jyokito 方剂和现代临床便秘适应症相关。目前，没有基于 PTP1B 抑制作用的 IR-T2DM 临床治疗方法。因此，我们建议将本研究中鉴定的汉方药作为强 PTP1B 抑制剂，可开发为治疗 IR-T2DM 的临床治疗剂。
