ABSTRACT
Our previous studies have shown that puerarin, an active component of the traditional Chinese medicine-Pueraria Lobata, can improve glycometabolism in high-fat diet (HFD) mice with diabetes by activating the glucagon-like peptide-1 receptor (GLP-1R) pathway. This study intends to further evaluate the effect of puerarin on depressive symptoms in HFD mice. Long-term HFD induces type 2 diabetes and depressive-like symptoms in mice. Animal welfare and experimental procedures follow the regulations of the Animal Ethics Committee of the Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Traditional Chinese Medicine (approval No. AEWC-025). The experiment was divided into: control group, model group, model/puerarin (150 mg·kg-1·day-1) group, and model/fluoxetine (15 mg·kg-1·day-1) group. The oral glucose tolerance test (OGTT) and behavioral experimental analysis were performed after 6 weeks of continuous administration. Afterwards, enzyme-linked immunosorbent assay (ELISA) was used to detect interleukin-1β (IL-1β), interleukin-6 (IL-6), 5-hydroxytryptamine (5-HT), and corticosterone (CORT) in serum of mice for each group. Western blot assays were used to detect the level of activation and expression of proteins related to neuroplasticity and depressive disorder in the hippocampus. Moreover, HT-22 cell line was used to investigate the protective effect of puerarin on cell morphology and survival. The results show that puerarin can effectively maintain the survival of HT22 in an environment with high glucose and corticosterone. Meantime, the glycemic regulation of diabetic mice was improved after treatment of puerarin, the depressive symptoms were alleviated, the 5-HT increased, and the corticosterone, IL-1β, and IL-6 decreased in the serum. The up-regulation of related proteins in GLP-1R/Wnt/mTOR (mammalian target of rapamycin) signaling in hippocampus suggests that its effect on ameliorating depression in diabetic mice may be related to the activation of GLP-1R/Wnt/mTOR signaling pathway. This study shows that puerarin can significantly ameliorate the depressive symptoms of HFD induced diabetic mice which might be achieved through activating the GLP-1R/Wnt/mTOR signaling pathway and improving hippocampal neuroplasticity.
ABSTRACT
Objective: To investigate the application characteristics of excipient copovidone in co-grinding process and the feasibility of co-grinding products for improving the dissolution of curcumin, using curcumin as a model drug in vitro. Methods: The prepared products were obtained by curcumin and various proportions (0%, 1%, 3%) of copovidone in co-grinding process, which were characterized by laser particle size analyzer, differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and X-ray powder diffraction (XRPD). The in vitro dissolution of milled products was evaluated in two media, and their accelerated stability was investigated. Results: In comparison with pure curcumin, the particle size of milled products decreased with the lower crystallinity by XRPD analysis, but the hygroscopicity and DSC thermograms showed no significant difference. Moreover, compared with pure curcumin, the products exhibited significant improvement of in vitro dissolution. Also, there was no significant difference in the dissolution behavior of products placed under the accelerated conditions (40 ℃, RH 75%) for three months, indicating their good stability. Conclusion: As a new excipient, copovidone could effectively enhance the dissolution of curcumin via co- grinding process. This study provided a feasible strategy for improving the solubility and even oral bioavailability of poorly soluble drugs.