| Summary: | 碩士 === 中山醫學大學 === 生物化學研究所 === 91 === Recent investigations highlight the antioxidant components of plant that may decreased the risk of inflammatory diseases and certain forms of cancer.The oxidative modification of low density lipoprotein plays a key role in the pathogenesis of atherosclerosis. Antioxidative reagents, which can effectively inhibit LDL oxidation, may prevent atherosclerosis via reducing early atherogenesis, and slowing down the progression to advance stages.
The major material of this experiment is anthocyanins which was extracted from dried Hibiscus sabdariffa L. by the acidic methanol. We found that only 5% anthocyanins could be extracted by acidic methanol as well as the purity could reach 85 to 90%. Two categories of anthocyanins were identified by the HPLC analysis. One is delphinidin that takes 3.7% of anthocyanins extraction, and the other one is cyanidin which holds 0.9% of anthocyanins extraction.
As shown in previous studies Hibiscus sabdariffa L. is a nature plant containing a lot of pigments that was found to possess antioxidative activity.In this study, we evaluated the antioxidative activity of the Hibiscus anthocyanins (HAs) by measuring their effects on LDL oxidation (in vitro) and anti-atherosclerotic abilities. The antioxidative activity of the extracts on LDL oxidation was defined by Apo B fragmentation, relative electrophoretic mobility (REM) and thiobarbituric acid-relative substances (TBARS) assay. Our results showed that HAs were able to inhibit the Apo B fragmentation, REM and TBARS assay in the Cu2+-mediated oxidative LDL. HAs also possessed the ability of DPPH radical scavenging. Taken together, HAs showed strong potency to inhibit the LDL oxidation induced by copper. When given low concentration of HAs, the expression of CD36 induced by OxLDL was reduced. Further studies demonstrated that HAs could reduce the cholesterol accumulation in macrophage, and that,subsequently, inhibit the formation of foam cells.
In conclusion, Hibiscus anthocyanins (HAs) possess strong antioxidative ability to inhibit LDL oxidation and foam cell formation. Therefore, it is suggestive the anthocyanins could be a healthy food to prevent individuals from atherosclerosis.
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