This study was designed to evaluate the antioxidant activity of methanol extract of Averrhoa carambolla Linn. leaves (MELA) using DPPH^· and ABTS^·+ free radical scavenging assays whereas its antineoplastic effect against Ehrlich ascites carcinoma (EAC) was assed using viable cell count, life span, body weight gain and hematological parameters of experimental mice. Results showed that rich phenolic and flavonoid content of MELA had moderate dose dependent free radical scavenging activity (IC₅₀: 62.0 μg/mL for DPPH^· and 6.0 μg/mL for ABTS^·+). In vivo antineoplastic assay, MELA significantly (P < 0.05) decreased viable cells and body weight gain, increased the survival time and restored altered hematological profiles of cancer cell bearing mice. Fluorescence microscopic view of EAC cells derived from MELA-treated group showed apoptotic characteristics and this observation was also supported by overexpression of pro-apoptotic genes coding p53 and Bax proteins in treated cancer cells. The anti-apoptotic genes coding Bcl-2 protein was also absent in treated EAC cells as compared with the control. Moreover, phytochemical profiles of MELA as identified by GC/MS analysis are also consistent with its activities.

本研究旨在评价杨桃甲醇提取物的抗氧化活性。使用DPPH ^·和ABTS ^·+自由基清除测定法测定叶(MELA)，而使用实验小鼠的活细胞计数、寿命、体重增加和血液学参数评估其对艾利希腹水癌(EAC)的抗肿瘤作用。结果表明，MELA 中丰富的酚类和类黄酮含量具有中等剂量依赖性的自由基清除活性（IC _{50 ：DPPH} ^· 62.0 μg/mL ，ABTS ^·+ 6.0 μg/mL ）。在体内抗肿瘤试验中，MELA 显着（P  < 0.05）减少活细胞和体重增加，延长携带癌细胞的小鼠的生存时间并恢复改变的血液学特征。来自 MELA 处理组的 EAC 细胞的荧光显微镜观察显示出凋亡特征，并且这一观察结果也得到了处理的癌细胞中编码 p53 和 Bax 蛋白的促凋亡基因的过度表达的支持。与对照相比，经处理的EAC细胞中也不存在编码Bcl-2蛋白的抗凋亡基因。此外，通过 GC/MS 分析鉴定的 MELA 植物化学特征也与其活性一致。