Inhibitory effect and action mechanisms of esculetin and protocatechuic acid on LDL oxidation

• Main Authors: Ming-Hsun Hsieh, 謝銘薰
• Other Authors: Song-Jui Shiow
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/18529931883782466962

碩士 === 中山醫學院 === 生物化學研究所 === 88 === 英文摘要 The oxidation of low-density lipoprotein (LDL) could increase the incidence of atherosclerosis. In previous studies showed that copper and nitroprusside possessed the ability to oxidize LDL in dose-dependent condition. They increased the negative charge existing in LDL and increased the electrophoretic mobility. On the other side, many antioxidants were observed to lower the formation of atherosclerosis such as Vit.E, Vit C and -carotene. These antioxidants reduced the relative electrophoretic mobilities (REM) and thiobarbituric acid-reactive substances (TBARS) induced by oxidative LDL in dose-depentently. In this thesis, we used both protocatechuic acid and esculetin to define the antioxidative activity in oxidative LDL by REM and TBARS. The data had showed that both of the antioxidants possessed strong antioxidative activity in oxidative LDL. Furthermore, the RAW264.7 macrophage cells were used to detect the effect of PCA in oxidative LDL-existed. The same results showed that PCA could inhibit the oxidative LDL. In the other part, we would like to discover the antioxidative mechanism of PCA to reduce oxidative LDL. In the results showed that oxidative LDL could induced the reduction of Bcl-2, Akt and some proteins working in MAPK signaling pathway. These reduced proteins could increase cell apoptosis, and death cell could accumulate on the vessel wall to progress atherosclerosis. When PCA pretreating, Akt, Bcl-2 and MAPK proteins increased in dose-dependently. Taken together, the mechanism of atherosclerosis prevented by PCA may be concluded that PCA reduced the apoptosis induced by oxidative LDL and lowered the progression of atherosclerosis.