Department of Surgery, Tao-Yuan General Hospital, Tao-Yuan County, Taiwan.
Eur J Clin Invest. 2010 Aug;40(8):713-21. doi: 10.1111/j.1365-2362.2010.02322.x. Epub 2010 Jun 14.
Polyphenol-rich longan seed extract (LSP) is a free radical scavenger and antioxidant. However, the effect of LSP on the growth of human colorectal carcinoma cells (CRC) has not yet been evaluated.
Polyphenols of longan seeds were extracted and measured by colorimetry. Four CRC cell lines (Colo 320DM, SW480, HT-29 and LoVo) were treated with LSP and assessed for viability by trypan blue exclusion, for cell cycle distribution by flow cytometry, for apoptosis by annexin V labelling and for changes in the levels of proteins involved in cell cycle control or apoptosis by immunoblotting.
Total phenol content of LSP was 695 mg g(-1) and total flavonoids were 150 mg g(-1). LSP inhibited the proliferation (25 microg mL(-1)-200 microg mL(-1)) of Colo 320DM, SW480 and HT-29, but not LoVo. LSP inhibited the proliferation by blocking cell cycle progression during the DNA synthesis phase and inducing apoptotic death. Western blotting indicated that LSP blocks the S phase, reducing the expression of cyclin A and cyclin D1. Colo 320DM and SW480 treated with LSP also showed the activation of caspase 3 and increased Bax : Bcl-2 ratio.
LSP induces S phase arrest of the cell cycle and apoptotic death in three CRC cell lines. The results indicate that LSP is a potential novel chemoprevention and treatment agent for colorectal cancer.
富含多酚的龙眼籽提取物（LSP）是一种自由基清除剂和抗氧化剂。然而，LSP 对人结直肠癌细胞（CRC）生长的影响尚未得到评估。
用比色法测定龙眼籽中的多酚。用 LSP 处理四种 CRC 细胞系（Colo 320DM、SW480、HT-29 和 LoVo），并通过台盼蓝排除法评估细胞活力，通过流式细胞术评估细胞周期分布，通过 Annexin V 标记评估细胞凋亡，通过免疫印迹评估参与细胞周期控制或细胞凋亡的蛋白质水平的变化。
LSP 的总酚含量为 695mg g(-1)，总黄酮含量为 150mg g(-1)。LSP（25μg mL(-1)-200μg mL(-1)）抑制 Colo 320DM、SW480 和 HT-29 的增殖，但不抑制 LoVo 的增殖。LSP 通过阻断 DNA 合成期的细胞周期进程并诱导细胞凋亡来抑制增殖。Western blot 表明，LSP 阻断 S 期，降低 cyclin A 和 cyclin D1 的表达。用 LSP 处理的 Colo 320DM 和 SW480 还显示 caspase 3 的激活和 Bax：Bcl-2 比值的增加。
LSP 诱导三种 CRC 细胞系的 S 期细胞周期停滞和细胞凋亡。结果表明，LSP 是结直肠癌的一种有潜力的新型化学预防和治疗药物。
