Department of Pharmaceutical Sciences, Faculty of Pharmacy, Chiang Mai University, Chiang Mai, 50200, Thailand.
Research Center of Pharmaceutical Nanotechnology, Chiang Mai University, Chiang Mai, 50200, Thailand.
Bioprocess Biosyst Eng. 2021 Jun;44(6):1289-1300. doi: 10.1007/s00449-020-02501-7. Epub 2021 Feb 27.
4-Allylpyrocatechol (APC), a major active compound of Piper betle, possesses strong antimicrobial activity. However, the water-insoluble property of APC limits its clinical and pharmaceutical use. To solve this problem, APC loaded polymeric micelles (PMAC) was fabricated using the thin-film hydration method. Nanoparticles of PMAC were characterized using a photon correlation spectrophotometer and transmission electron microscope (TEM). Antibiofilm activity of PMAC was investigated using crystal violet assay and confocal laser scanning microscopy (CLSM). Cytotoxic effects of PMAC on normal cells were investigated using MTT assay. The results demonstrate that a ratio of APC to the polymer plays an important role in the physicochemical characteristics of PMAC. The most suitable PMAC formulation having a small particle size (38.8 ± 1.4 nm), narrow size distribution (0.28 ± 0.10), a high negative zeta potential (- 16.43 ± 0.55 mV), and high entrapment efficiency (86.33 ± 14.27%) can be obtained from the ratio 1:4. The water solubility of this PMAC is significantly improved, approximately 1,000-fold higher than the unentrapped APC. TEM images demonstrate that PMAC is spherical in shape. The inhibitory effects of PMAC (1.5 mg APC/mL) against Streptococcus intermedius and Streptococcus mutans biofilms are significantly stronger than chlorhexidine (0.06 mg/mL). Images from CLSM demonstrate the destruction and thickness reduction of the pathogenic biofilms after contacting with PMAC. The MTT assay confirms that PMAC at this concentration is non-toxic to normal cells. These results obviously indicate that PMAC is a promising natural and harmless antimicrobial agent suitable for use in the oral cavity for inhibition of pathogenic bacterial biofilms.
4-丙烯基儿茶酚（APC）是菝葜的主要活性化合物，具有很强的抗菌活性。然而，APC 的水溶性差限制了其在临床和制药方面的应用。为了解决这个问题，采用薄膜水化法制备 APC 载药聚合物胶束（PMAC）。使用光子相关光谱仪和透射电子显微镜（TEM）对 PMAC 纳米粒进行了表征。采用结晶紫法和共聚焦激光扫描显微镜（CLSM）研究了 PMAC 的抗生物膜活性。采用 MTT 法研究了 PMAC 对正常细胞的细胞毒性作用。结果表明，APC 与聚合物的比例对 PMAC 的理化特性起着重要作用。最合适的 PMAC 制剂具有较小的粒径（38.8 ± 1.4nm）、较窄的粒径分布（0.28 ± 0.10）、较高的负 zeta 电位（-16.43 ± 0.55mV）和较高的包封率（86.33 ± 14.27%），其比例为 1:4。这种 PMAC 的水溶性得到了显著提高，大约是未包封 APC 的 1000 倍。TEM 图像表明 PMAC 呈球形。PMAC（1.5mg APC/mL）对中间链球菌和变形链球菌生物膜的抑制作用明显强于洗必泰（0.06mg/mL）。CLSM 图像显示，接触 PMAC 后，致病菌生物膜被破坏，厚度变薄。MTT 试验证实，该浓度的 PMAC 对正常细胞无毒。这些结果明显表明，PMAC 是一种有前途的天然、无害的抗菌剂，适用于口腔抑制致病菌生物膜。
