Plantas y cáncer

Los extractos de tomates verdes (no maduros) que contienen tomatina, un glicoalcaloide, inhiben el crecimiento de tumores de mama, colon, hígado y estómago.

• Tomatine-Containing Green Tomato Extracts Inhibit Growth of Human Breast, Colon, Liver, and Stomach Cancer Cells

Mendel Friedman, Carol E. Levin, Seung-Un Lee, Hyun-Jeong Kim, In-Seon Lee, Jae-Oke Byun and Nobuyuki Kozukue

J. Agric. Food Chem., Publication Date (Web): June 10, 2009

Abstract

Tomato plants (Lycopersicon esculentum) synthesize the glycoalkaloids dehydrotomatine and a-tomatine, possibly as a defense against bacteria, fungi, viruses, and insects. Six green and three red tomato extracts were investigated for their ability to induce cell death in human cancer and normal cells using a microculture tetrazolium (MTT) assay. Compared to untreated controls, the high-tomatine green tomato extracts strongly inhibited the following human cancer cell lines: breast (MCF-7), colon (HT-29), gastric (AGS), and hepatoma (liver) (HepG2), as well as normal human liver cells (Chang). There was little inhibition of the cells by the three low-tomatine red tomato extracts. Cell death induced by the pure glycoalkaloids dehydrotomatine and a-tomatine isolated from green tomatoes and characterized by HPLC, GC, and GC-MS, as well as their respective aglycones tomatidenol and tomatidine, was also evaluated. a-Tomatine was highly effective in inhibiting all of the cell lines. Dehydrotomatine, tomatidenol, and tomatidine had little, if any, effect on cell inhibition. The results show that the susceptibility to destruction varies with the nature of the alkaloid and plant extract and the type of cancer cell. These findings extend related observations on the anticarcinogenic potential of glycoalkaloids and suggest that consumers may benefit by eating not only high-lycopene red tomatoes but also green tomatoes containing glycoalkaloids. Possible mechanisms of the anticarcinogenic and other beneficial effects and the significance of the cited observations for breeding improved tomatoes and for the human diet are discussed.

Los extractos de la manzana inhiben la proliferación de las células cancerosas que dependen de los estrógenos y las que no dependen de ellos, en el cáncer de mama humano.

• Apple Phytochemical Extracts Inhibit Proliferation of Estrogen-Dependent and Estrogen-Independent Human Breast Cancer Cells through Cell Cycle Modulation

Jie Sun† and Rui Hai Liu*†‡

Department of Food Science and Institute of Comparative and Environmental Toxicology, Cornell University, Ithaca, New York  14853

J. Agric. Food Chem., 2008, 56 (24), pp 11661–11667

Abstract

Breast cancer is the most commonly diagnosed cancer in women in the United States. Dietary modification, particularly increased intake of fruits and vegetables, has been consistently associated with a reduced risk of various cancers, including breast cancer. Apples are a major source of dietary phytochemicals and flavonoids and possess potent antioxidant activity andantiproliferative activity in vitro. However, the molecular mechanisms of the anticancer properties of apple phytochemicalextracts are not completely understood. In this study a possible mechanism by which apple extracts could inhibit cancer cellgrowth in vitro using estrogen-dependent MCF-7 and estrogen-independent MDA-MB-231 human breast cancer cell lines wasanalyzed. The data showed that apple phytochemical extracts significantly inhibited human breast cancer MCF-7 andMDA-MB-231 cell proliferation at concentrations of 10?80 mg/mL (p < 0.05). DNA flow cytometric analysis showed that appleextracts significantly induced G1 arrest in MCF-7 cells in a dose-dependent manner at concentrations >20 mg/mL (p < 0.05). Atconcentrations of 15, 30, and 50 mg/mL, apple extracts caused a greater increase in the G1/S ratio in MDA-MB-231 cells whencompared with MCF-7 cells (p < 0.05). Cyclin D1 and Cdk4 proteins, the two major G1/S transit regulators, decreased in adose-dependent manner after exposure to apple extracts. These results suggest that the antiproliferative activities of applephytochemical extracts toward human breast cancer cells might be due to the modulation effects on cell cycle machinery.

• Apoptotic Effects of Protocatechuic Acid in Human Breast, Lung, Liver, Cervix, and Prostate Cancer Cells: Potential Mechanisms of Action

Mei-Chin Yin†, Chun-Che Lin, Hsi-Chin Wu§, Shih-Ming Tsao and Cheng-Kuang Hsu

Department of Nutrition, China Medical University, 91, Hsueh-shih Road, Taichung City, Taiwan, ROCDepartment of Internal Medicine, Chung Shan Medical University Hospital, Taichung City, Taiwan, ROC§Department of Urology, China Medical University and Hospital, Taichung City, Taiwan, ROC Department of Health and Nutrition Biotechnology, Asia University, Taichung County, Taiwan, ROC

J. Agric. Food Chem., Publication Date (Web): June 23, 2009

Abstract

Apoptotic effects of protocatechuic acid (PCA) at 1, 2, 4, 8 µmol/L on human breast cancer MCF7 cell, lung cancer A549 cell, HepG2 cell, cervix HeLa cell, and prostate cancer LNCaP cell were examined. Results showed that PCA concentration-dependently decreased cell viability, increased lactate dehydrogenase leakage, enhanced DNA fragmentation, reduced mitochondrial membrane potential, and lowered Na+-K+-ATPase activity for these cancer cells (P < 0.05). PCA also concentration-dependently elevated caspase-3 activity in five cancer cells (P < 0.05), but this agent at 2-8 µmol/L significantly increased caspase-8 activity (P < 0.05). PCA concentration-dependently decreased intercellular adhesion molecule level in test cancer cells (P < 0.05) but significantly inhibited cell adhesion at 2-8 µmol/L (P < 0.05). PCA also concentration-dependently lowered the levels of interleukin (IL)-6 and IL-8 in five cancer cells (P < 0.05), but this agent at 2-8 µmol/L significantly suppressed vascular endothelial growth factor production (P < 0.05). These findings suggest that PCA is a potent anticancer agent to cause apoptosis or retard invasion and metastasis in these five cancer cells.