| 摘要: | 原兒茶酸為一多酚化合物, 廣布於蔬菜水果花核桃中, 過去報告指出其具抗養化活性, 及對化學致癌物誘導之消化臟器癌化具有保護作用, 本研究發現其對人類白血癌細胞的生長有抑制作用, 當細胞以PCA (>0.75mM)處裡時, 細胞形態會改變, 其核會萎縮, 細胞膜有泡奘狀突出, 細胞核濃染, 再由DNA電泳發現有片斷DNA形成, 因此推測其發生凋謝死亡. 處理過PCA的細苞, 以flowcytometry偵測發現其週期被阻擋在G1 phase, 且apoptotic peak於6小時後明顯增加, 除此之外PCA能降低細胞內GSH含量與膜電位, 另外也降低了BCL-2的表現, 因此綜合以上結果推測pca所誘導的HL-60凋謝死亡經由破壞粒線體完整之功能, 抑制BCL-2 PROTEIN的表現, 與改變RB protein的磷酸化.
Induction of apoptosis by protocatechuic acid in human leukemia cells. protocatechuic acid (PCA), a phenolic
compound, exhibited antioxidant, antimutagenic activity and anticarcinogenic effect previously. In the present study, it showed significantly inhibitory effect on the proli- -feration of human leukemia cells (HL-60) at the concentration above 0.75 mM. Treatment with PCA resulted in morphology changes, including reduction of cell volumn, condensation of nuclear chromatin, loss of membrane integrity, generation of apoptotic bodies as well as formation internuclesomal DNA fragmentation. In addition, the hypodiploid DNA peak of propidium iodide-stained nuclei was revealed, and cell cycle was arrest at G1 phase. To explore possible mechanism of PCA-induced apoptosis, we investigated th RB protein, BCL-2 protein, GSH and membrane potential. We proposed that PCA induced apoptosis by inhibition of BCL-2 protein expression and destruction of mitochondria. In addition, unusual phospho--rylation and dephosphorylation of RB
protein might play another role in induction of apoptosis |
