Curcumin hybrid molecules for the treatment of Alzheimer's disease: Structure and pharmacological activities.

Alzheimer's disease (AD) is the most common neurodegenerative disease among the elderly. Contemporary treatments can only relieve symptoms but fail to delay disease progression. Curcumin is a naturally derived compound that has demonstrated significant therapeutic effects in AD treatment. Recently, molecular hybridization has been utilized to combine the pharmacophoric groups present in curcumin with those of other AD drugs, resulting in a series of novel compounds that enhance the therapeutic efficacy through multiple mechanisms. In this review, we firstly provide a concise summary of various pathogenetic hypotheses of AD and the mechanism of action of curcumin in AD, as well as the concept of molecular hybridization. Subsequently, we focus on the recent development of hybrid molecules derived from curcumin, summarizing their structures and pharmacological activities, including cholinesterase inhibitory activity, Aß aggregation inhibitory activity, antioxidant activity, and other activities. The structure-activity relationships were further discussed.

Treatment with quercetin inhibits SARS-CoV-2 N protein-induced acute kidney injury by blocking Smad3-dependent G1 cell-cycle arrest.

Increasing evidence shows that SARS-CoV-2 can infect kidneys and cause acute kidney injury (AKI) in critically ill COVID-19 patients. However, mechanisms through which COVID-19 induces AKI are largely unknown, and treatment remains ineffective. Here, we report that kidney-specific overexpressing SARS-CoV-2 N gene can cause AKI, including tubular necrosis and elevated levels of serum creatinine and BUN in 8-week-old diabetic db/db mice, which become worse in those with older age (16 weeks) and underlying diabetic kidney disease (DKD). Treatment with quercetin, a purified product from traditional Chinese medicine (TCM) that shows effective treatment of COVID-19 patients, can significantly inhibit SARS-CoV-2 N protein-induced AKI in diabetic mice with or without underlying DKD. Mechanistically, quercetin can block the binding of SARS-CoV-2 N protein to Smad3, thereby inhibiting Smad3 signaling and Smad3-mediated cell death via the p16-dependent G1 cell-cycle arrest mechanism in vivo and in vitro. In conclusion, SARS-CoV-2 N protein is pathogenic and can cause severe AKI in diabetic mice, particularly in those with older age and pre-existing DKD, via the Smad3-dependent G1 cell-cycle arrest mechanism. Importantly, we identify that quercetin may be an effective TCM compound capable of inhibiting COVID-19 AKI by blocking SARS-CoV-2 N-Smad3-mediated cell death pathway.

7-Hydroxycoumarin protects against cisplatin-induced acute kidney injury by inhibiting necroptosis and promoting Sox9-mediated tubular epithelial cell proliferation.

BACKGROUND: 7-Hydroxycoumarin (7-HC), also known as umbelliferon, is commonly found in Chinese herbs (e.g. Eucommiae Cortex, Prunellae Spica, Radix Angelicae Biseratae). Previous laboratory studies have indicated that 7-HC has anti-inflammatory, anti-oxidative, and anti-tumor effects. Cisplatin is a widely used chemotherapeutic agent for cancer. Nephrotoxicity is one of the limiting side effects of cisplatin use. PURPOSE: This study aimed to evaluate the renoprotective effect of 7-HC in a cisplatin-induced acute kidney injury (AKI) mouse model. METHODS: AKI was induced in male C57BL/6 mice (aged 6-8 weeks) by a single intraperitoneal injection of cisplatin at 20 mg/kg. The mice received 7-HC at 30, 60, and 90 mg/kg intraperitoneally before or after cisplatin administration. Renal function, necroptosis, and cell proliferation were measured. Mechanisms underlying the reno-protective effect of 7-HC were explored in renal tubular epithelial cells treated with or without cisplatin. RESULTS: In-vivo experiments showed that 7-HC significantly improved the loss in kidney function induced by cisplatin, as indicated by lower levels of serum creatinine and blood urea nitrogen, in AKI mice. Consistent herewith, cisplatin-induced tubular damage was alleviated by 7-HC as shown by morphological (periodic acid-Schiff staining) and kidney injury marker (KIM-1) analyses. We found that 7-HC suppressed renal necroptosis via the RIPK1/RIPK3/MLKL pathway and accelerated renal repair as evidenced by the upregulation of cyclin D1 in cisplatin-induced nephropathy. In-vitro experiments showed that knockdown of Sox9 attenuated the suppressive effect of 7-HC on KIM-1 and reversed the stimulatory effect of 7-HC on cyclin D1 expression in cisplatin-treated HK-2 cells, indicating that 7-HC may protect against AKI via a Sox9-dependent mechanism. CONCLUSION: 7-HC inhibits cisplatin-induced AKI by suppressing RIPK1/RIPK3/MLKL-mediated necroptosis and promoting Sox9-mediated tubular epithelial cell proliferation. 7-HC may serve as a preventive and therapeutic agent for AKI.

Efficacy of Fu-Yuan Capsule in the Healing of Fractures of the Lower End of the Radius in a Rabbit Model.

OBJECTIVE: The aim of the study was to explore the efficacy of Fu-Yuan Capsule in the healing of fractures of the lower end of the radius in a rabbit model. METHODS: After establishing a rabbit fracture model, all animals were randomly divided into the model group (n = 24), the Fu-Yuan Capsule group (n = 24), and the Shenyang Hongyao group (n = 24). The X-ray was applied to observe the course of fracture healing at 2, 4, 6, and 8 weeks after treatment. Haematoxylin-eosin staining and immunohistochemical staining were used to determine the histological change and the expression of bone morphogenetic protein-2 (BMP-2). Serum alkaline phosphatase (ALP), calcium, and phosphorus levels were detected before and after treatment. RESULTS: X-ray showed that the Fu-Yuan Capsule and Shenyang Hongyao groups exhibited abundant callus shadow areas than the model group in a time-dependent manner. In the model group, the fractures exhibited poor recovery with fibrous callus and obstructed bone marrow cavity. In the Fu-Yuan Capsule and Shenyang Hongyao groups, the fracture showed good recovery and restored normal structure with an effective remodeling of the lamellar bone. Immunohistochemical staining showed that the Fu-Yuan Capsule and Shenyang Hongyao groups had higher expressions of BMP-2 than the model group. Furthermore, serum ALP and calcium-phosphorus product in the Fu-Yuan Capsule and Shenyang Hongyao groups were higher than what they were in the model group. CONCLUSIONS: These results suggest that Fu-Yuan Capsule could promote the fracture healing through upregulating BMP-2 expression and increasing serum ALP and calcium-phosphorus product.