Graduate School of Biotechnology, College of Life Science, Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Korea.
Department of Oriental Medicinal Biotechnology, College of Life Science, Kyung Hee University, Yongin-si, Gyeonggi-do 17104, Korea.
Molecules. 2019 Nov 29;24(23):4367. doi: 10.3390/molecules24234367.
Low solubility and tumor-targeted delivery of ginsenosides to avoid off-target cytotoxicity are challenges for clinical trials. In the present study, we report on a methodology for the synthesis of polyethylene glycol (PEG)-ginsenoside conjugates through a hydrolysable ester bond using the hydrophilic polymer polyethylene glycol with the hydrophobic ginsenosides Rh1 and Rh2 to enhance water solubility and passive targeted delivery. The resulting conjugates were characterized by H nuclear magnetic resonance (H NMR) and Fourier-transform infrared spectroscopy (FT-IR). H NMR revealed that the C-6 and C-3 sugar hydroxyl groups of Rh1 and Rh2 were esterified. The conjugates showed spherical shapes that were monitored by field-emission transmission electron microscopy (FE-TEM), and the average sizes of the particles were 62 ± 5.72 nm and 134 ± 8.75 nm for PEG-Rh1and PEG-Rh2, respectively (measured using a particle size analyzer). Owing to the hydrophilic enhancing properties of PEG, PEG-Rh1 and PEG-Rh2 solubility was greatly enhanced compared to Rh1 and Rh2 alone. The release rates of Rh1 and Rh2 were increased in lower pH conditions (pH 5.0), that for pathophysiological sites as well as for intracellular endosomes and lysosomes, compared to normal-cell pH conditions (pH 7.4). In vitro cytotoxicity assays showed that the PEG-Rh1conjugates had greater anticancer activity in a human non-small cell lung cancer cell line (A549) compared to Rh1 alone, whereas PEG-Rh2 showed lower cytotoxicity in lung cancer cells. On the other hand, both PEG-Rh1 and PEG-Rh2 showed non-cytotoxicity in a nondiseased murine macrophage cell line (RAW 264.7) compared to free Rh1 and Rh2, but PEG-Rh2 exhibited increased efficacy against inflammation by greatly inhibiting nitric oxide production. Thus, the overall conclusion of our study is that PEG conjugation promotes the properties of Rh1 for anticancer and Rh2 for inflammation treatments. Depends on the disease models, they could be potential drug candidates for further studies.
低溶解性和肿瘤靶向递送人参皂苷以避免脱靶细胞毒性是临床试验面临的挑战。在本研究中，我们报告了一种通过可水解酯键合成聚乙二醇（PEG）-人参皂苷缀合物的方法，该方法使用亲水性聚合物聚乙二醇与疏水性人参皂苷 Rh1 和 Rh2 结合，以提高水溶解度和被动靶向递送。所得缀合物通过氢核磁共振（H NMR）和傅里叶变换红外光谱（FT-IR）进行了表征。H NMR 表明 Rh1 和 Rh2 的 C-6 和 C-3 糖羟基被酯化。通过场发射透射电子显微镜（FE-TEM）监测到缀合物呈球形，通过粒径分析仪测量，PEG-Rh1 和 PEG-Rh2 的颗粒平均尺寸分别为 62±5.72nm 和 134±8.75nm。由于 PEG 的亲水性增强特性，与单独的 Rh1 和 Rh2 相比，PEG-Rh1 和 PEG-Rh2 的溶解度大大提高。与正常细胞 pH 条件（pH 7.4）相比，在较低 pH 条件（pH 5.0）下，Rh1 和 Rh2 的释放速率增加，这有利于病理生理部位以及细胞内内体和溶酶体。体外细胞毒性试验表明，与单独的 Rh1 相比，PEG-Rh1 缀合物在人非小细胞肺癌细胞系（A549）中具有更强的抗癌活性，而 PEG-Rh2 在肺癌细胞中的细胞毒性较低。另一方面，与游离 Rh1 和 Rh2 相比，PEG-Rh1 和 PEG-Rh2 在非疾病状态的鼠巨噬细胞系（RAW 264.7）中均无细胞毒性，但 PEG-Rh2 通过大大抑制一氧化氮产生，对炎症具有更高的疗效。因此，我们研究的总体结论是，PEG 缀合促进了 Rh1 的抗癌和 Rh2 的抗炎作用。根据疾病模型，它们可能是进一步研究的潜在候选药物。
