Ellagic Acid, a Dietary Polyphenol, Selectively Cytotoxic to HSC-2 Oral Carcinoma Cells.

Background: The antiproliferative and apoptotic effects of ellagic acid, a dietary polyphenol, were studied.

Materials And Methods: The neutral red cytotoxicity assay compared the sensitivities of gingival fibroblasts and HSC-2 oral carcinoma cells to ellagic acid. The ferrous ion oxidation xylenol orange assay and levels of intracellular reduced glutathione were used to assess pro-oxidant nature of ellagic acid.

Research strategies in the study of the pro-oxidant nature of polyphenol nutraceuticals.

Polyphenols of phytochemicals are thought to exhibit chemopreventive effects against cancer. These plant-derived antioxidant polyphenols have a dual nature, also acting as pro-oxidants, generating reactive oxygen species (ROS), and causing oxidative stress. When studying the overall cytotoxicity of polyphenols, research strategies need to distinguish the cytotoxic component derived from the polyphenol per se from that derived from the generated ROS.

Pomegranate extract, a prooxidant with antiproliferative and proapoptotic activities preferentially towards carcinoma cells.

The antiproliferative and proapoptotic effects of pomegranate extract (PE), as correlated with its prooxidant activity, were studied. PE exerted greater antiproliferative effects towards cancer, than to normal, cells, isolated from the human oral cavity. In cell-free systems, PE generated hydrogen peroxide (H(2)O(2)) in cell culture media and in phosphate buffered saline, with prooxidant activity increasing from acidic to alkaline pH, and oxidized glutathione (GSH) in an alkaline, phosphate buffer.

Gingko biloba leaf extract induces oxidative stress in carcinoma HSC-2 cells.

The antiproliferative effects of a Gingko biloba leaf extract to cells from tissues of the human oral cavity were studied. Toxicity to carcinoma HSC-2 cells was correlated with the prooxidative nature of the extract. G.

Theaflavin-3,3'-digallate, a component of black tea: an inducer of oxidative stress and apoptosis.

Treatment of human oral squamous carcinoma HSC-2 cells and normal GN46 fibroblasts with theaflavin-3,3'-digallate (TF-3), a polyphenol in black tea, showed a concentration and time dependent inhibition of growth, with the tumor cells more sensitive than the fibroblasts. In buffer and in cell culture medium, TF-3 generated reactive oxygen species, with lower levels detected in buffer amended with catalase and superoxide dismutase, indicating the generation of hydrogen peroxide and superoxide, respectively, and suggesting that TF-3 may be an inducer of oxidative stress. The toxicity of TF-3 was decreased in the presence of catalase, pyruvate, and divalent cobalt, all scavengers of reactive oxygen species, but was potentiated in the presence of diethyldithiocarbamate, an inhibitor of superoxide dismutase.