Anti-diabetic effects of Protaetia brevitarsis in pancreatic islets and a murine diabetic model.

OBJECTIVE: In this study, the antidiabetic efficacy of Protaetia brevitarsis in alloxan-treated pancreatic islets and db/db mice was investigated. P. brevitarsis was tested for alloxan-mediated cytotoxicity and nitric oxide production in mice pancreatic islets. MATERIALS AND METHODS: The anti-diabetic effect of P. brevitarsis was also evaluated in db/db mice after 4 weeks of administration. Biochemical analysis, oral glucose tolerance test (OGTT), and pancreatic histological analysis were performed. RESULTS: P. brevitarsis displayed hypoglycemic activity in alloxan-treated mice pancreatic islets. Our results showed that P. brevitarsis protects pancreatic islets from cytotoxicity. Moreover, daily oral supplementation with P. brevitarsis for 4 weeks reduced plasma glucose levels without affecting body weight and food intake, elevated glucose tolerance in OGTT, improved blood lipid parameters, inhibited fat accumulation, and restored islet structure of db/db mice. CONCLUSIONS: The present study provided evidence for the anti­diabetic effect of P. brevitarsis in alloxan-treated pancreatic islets and db/db mice. These results suggest that P. brevitarsis may be used as an adjunctive anti-diabetic agent or as a functional food.

Cordycepin inhibits IL-1beta-induced MMP-1 and MMP-3 expression in rheumatoid arthritis synovial fibroblasts.

OBJECTIVE: MMP is a key enzyme in the degradation of extracellular matrices, and its expression plays important roles in inflammatory diseases. Cordycepin (3'-deoxyadenosine), a bioactive compound of Cordyceps militaris, has been shown to exhibit many pharmacological activities, such as anti-cancer, anti-inflammatory and anti-infection activities. In this study, we aimed at the inhibitory effect of cordycepin on IL-1beta-induced MMP-1 and MMP-3 expression as well as the molecular basis using RA synovial fibroblasts (RASFs). METHODS: RASFs were isolated from synovial tissue obtained from 12 patients with RA and cultured in monolayer. Expression of MMP-1 and MMP-3 was evaluated using western blotting and real-time PCR. Chemokines were analysed by ELISA. The phosphorylation of mitogen-activated protein kinase was measured by western blotting. Electrophoretic mobility shift assay was performed to evaluate binding activities of DNA to nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1). RESULTS: Cordycepin inhibited IL-1beta-induced MMP-1 and MMP-3 expressions in RASFs in a dose-dependent manner. Among various chemokines [such as monocyte chemoattractant protein-1 (MCP-1), GRO-alpha, regulated upon activation, normal T-cell expressed and presumably secreted (RANTES) and epithelial neutrophil activating peptide 78 (ENA-78)], cordycepin specifically blocked IL-1beta-induced ENA-78 production in RASF. Moreover, cordycepin significantly inhibited IL-1beta-induced p38/JNK and AP-1 activation, but not extracellular signal-regulated kinase (ERK) and NF-kappaB activation. CONCLUSIONS: Cordycepin is a potent inhibitor of IL-1beta-induced chemokine production and MMP expression and strongly blocks the p38/JNK/AP-1 signalling pathway in RASFs.