Chuihao Kong,1,2,* Kaidi Wang,1,2,* Lei Sun,1,3 Hongsu Zhao,1,2 Tongsheng Wang,1 Wuxi Zhou,1 Deling Wu,1,2 Fengqing Xu1,2 

1School of Pharmacy, Anhui University of Chinese Medicine, Hefei, 230012, People’s Republic of China; 2Anhui Province Key Laboratory of New Manufacturing Technology for Traditional Chinese Medicine Decoction Pieces, Hefei, 230012, People’s Republic of China; 3Zhejiang CONBA Pharmaceutical Co. LTD, Hangzhou, 310052, People’s Republic of China

*These authors contributed equally to this work

Correspondence: Wuxi Zhou; Fengqing Xu, School of Pharmacy, Anhui University of Chinese Medicine, 350 Longzihu Road, Xinzhan District, Hefei, 230012, People’s Republic of China, Email zhouwuxi@ahtcm.edu.cn; xufengqing@ahtcm.edu.cn

Background: Mangiferin (MA), a bioactive C-glucosyl xanthone with a wide range of interesting therapeutic properties, has recently attracted considerable attention. However, its application in biomedicine is limited by poor solubility and bioavailability. Carbon dots (CDs), novel nanomaterials, have immense promise as carriers for improving the biopharmaceutical properties of active components because of their outstanding characteristics.
Methods: In this study, a novel water-soluble carbon dot (MC-CDs) was prepared for the first time from an aqueous extract of Moutan Cortex Carbonisata, and characterized by various spectroscopies, zeta potential and high-resolution transmission electron microscopy (HRTEM). The toxicity effect was investigated using the CCK-8 assay in vitro. In addition, the potential of MC-CDs as carriers for improving the pharmacokinetic parameters was evaluated in vivo.
Results: The results indicated that MC-CDs with a uniform spherical particle size of 1– 5 nm were successfully prepared, which significantly increased the solubility of MA in water. The MC-CDs exhibited low toxicity in HT-22 cells. Most importantly, the MC-CDs effectively affected the pharmacokinetic parameters of MA in normal rats. UPLC-MS analysis indicated that the area under the maximum blood concentration of MA from mangiferin-MC-CDs (MA-MC-CDs) was 1.6-fold higher than that from the MA suspension liquid (MA control) after oral administration at a dose of 20 mg/kg.
Conclusion: Moutan Cortex-derived novel CDs exhibited superior performance in improving the solubility and bioavailability of MA. This study not only opens new possibilities for the future clinical application of MA but also provides evidence for the development of green biological carbon dots as a drug delivery system to improve the biopharmaceutical properties of insoluble drugs.

Keywords: Moutan Cortex, carbon dots, mangiferin, solubility, bioavailability