| Summary: | 碩士 === 台北醫學院 === 生藥學研究所 === 88 === Diabetes mellitus is a generalized chronic disease and the complication of diabetes mellitus including dermopathy, inflammation and sepsis occur frequently in patients. In this study, nineteen coumarins- related compounds and twenty-eight polysaccharides isolated from natural products were used to study their effects on insulin secretion and anti-inflammation in HIT-T15 and RAW 264.7 cells, respectively.
In HIT-T15 cells, the effects of coumarins and polysaccharides extracts were studied on insulin release by radioimmuno assay (RIA). Among these courmarins, phellopterin obviously stimulated insulin secretion and the insulin secretion was decreased by 33%, 60% and 92% in EDTA, EGTA and Nifedipine added reaction. On the other experiment, glabra-lactone , a kind of courmarins showed the significant inhibitory activity on LPS-induced NO and PGE2 production in RAW 264.7 macrophage cells and the IC50 value is 3.85 mg/mL and 35.58 mg/mL, respectively. By MTT assay, glabra-lactone showed less cytotoxicity in RAW 264.7 cells. In the same experiment, glabra-lactone was unable to inhibit NOS enzyme activity by indirect or direct NOS enzyme activity assays. Western blot analysis of iNOS and COX-2 proteins, showed that glabra-lactone effectively inhibited the expression of the LPS-inducible iNOS and COX-2 genes. Therefore, glabra-lactone might be a promising natural product in the treatment of LPS-induced response and deserves further study.
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