Examination of the Enhancing or inhibitory effects of Food or Food-derived Compounds on the Production of Prostaglandin E2 by a Macrophage Cell Line
| Autor: | Mei-chiao Wu, 吳美嬌 |
|---|---|
| Rok vydání: | 2000 |
| Druh dokumentu: | 學位論文 ; thesis |
| Popis: | 88 PGE2 is an important mediator for biological and pathological. Cyclooxygenase is the enzyme which catalyzes the first two steps in the biosynthesis of the PGE2 from arachidonic acid. There are two distinct isozymes of cyclooxygenase which are inducible COX-2 and constitutive COX-1. PGE2 production have been implicated in the process of inflammation. The present studies focused on selective inhibition for COX-2. Some antioxidants from dietary plants, such as polyphenols and flavonoids, have been shown as an inhibitor of the COX-2 enzyme and reduces the production of PGE2. In this study, we screened the enhancement or inhibition factors in foods or food components on PGE2 production using macrophage as a model. The food materials were extracted by water and ethyl acetate to obtain water extract and ethyl acetate extract fractions. The RAW264.7 cells were co-treated with samples and LPS (1 ng/mL) or without LPS for 18 hours, and PGE2 produced was determined by an EIA kit. In order to examine the effect of sample on the COX-2 protein, cells were treated with samples and LPS or samples only for 12 hours. Cells were then collected and analyzed for COX-2 protein by western blot. The water extracts of soybean isoflavonoid fraction fractions、Chrysanthemum、onion、bitter gourd and lotus seed core significantly reduced PGE2 production in LPS-activated RAW264.7 cells; the IC50 were 0.17、0.6、0.5、0.13、0.08 mg/mL, respectively. Inhibition of PGE2 production was also observed when cells were co-treated for 18 hours with LPS and the ethyl acetate extracts from onion, bitter gourd and lotus seed core. The water extract of soybean isoflavonoid fractions also inhibited the expression of COX-2 protein in LPS-activated RAW264.7 cells. The water extract from longan、dried longan、litchi and celery significantly increased the production of PGE2 in RAW264.7, the EC50 were 16、11、8.4 mg/mL, respectively. Western blot analyses demonstrated that water extracts from longan、dried longan、litchi and celery induced protein expression of COX-2. The flavonoids, including: apigenin、quercetin、naringenin, reduced the production of PGE2 in LPS-activated RAW264.7 cells and IC50 were 1.9、23.28、36.74 mM, respectively. Inhibition of PGE2 production was observed in cells co-treated with LPS and green tea polyphenols: inculding EGCG、ECG、(-)EC、catechin、EGC. The IC50 for EGCG、ECG、(-)EC、catechin were 11.3、39.2、151、321 mM, respectively. Resveratrol、curcumin、Vit C were also found to be an inhibitor for PGE2 production and IC50 were 9.7、13.9、833 mM, respectively. In contrast, β-carotene showed no effect on PGE2 production in LPS-activated RAW264.7 cells. Expression of COX-2 protein in activated macrophage treated with curcumin、resveratrol、Vit C、quercetin, naringenin and green tea polyphenols were not significantly different from that of the control cells. In conclusion, the water extracts of soybean isoflavonoid fraction、Chrysanthemum、onion、bitter gourd and lotus seed core reduced the production of PGE2 in LPS-activated macrophage. In contrast, longan、dried longan and litchi increased PGE2 production and COX-2 expression in RAW264.7 cells. Inhibitions of PGE2 production in activated macrophages were also observed with apigenin、quercetin、naringenin、resveratrol、curcumin、EGCG、ECG、EGC、catechin and Vit C. Results of the present study provide important information for patients suffered from inflammation disease. They may ameliorate their inflammation condition by selecting foods properly based on results of the present study. |
| Databáze: | Networked Digital Library of Theses & Dissertations |
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