Phenolic composition, antioxidant capacity and in vitro cancer cell cytotoxicity of nine prickly pear (Opuntia spp.) juices.

Juices of nine prickly pears (Opuntia spp.) were characterized in terms of color, acidity, sugar content, phenolics, flavonoids, betalains and antioxidant activity and tested in vitro against four cancer cell lines. The juices had pH s, acidities and sugar ranging from 4.27 to 5.46, 0.03 to 0.27% and 8 to 14.7 degrees Brix, respectively. Juices also varied in color from white to purple and contained total phenolics, flavonoids, betaxanthins, betacyanins and antioxidant capacity ranging from 22 to 226 microg gallic acid eq/g, 95 to 374 microg quercetin eq/g, 3 to 189 microg/g, 1.6 to 300 microg/g and 17 to 25 micromoles Trolox eq./mL, respectively. Among the cancer lines tested, viability of prostate and colon cells were the most affected. Moradillo contained the highest flavonoids and diminished both prostate and colon cancer cell viability without affecting mammary or hepatic cancer cells. Rastrero reduced the growth of the four cancer cell lines without affecting normal fibroblast viability. The research shows intervarietal differences among prickly pears in terms of juice properties and phytochemicals that could prevent oxidative stress and cancer.

Comparison of cytotoxicity and genotoxicity effects of silver nanoparticles on human cervix and breast cancer cell lines.

The wide application of silver nanoparticles (AgNPs) has pointed out the need to evaluate their potential risk and toxic effects on human health. Herein, the cytotoxic effects of Argovit™ AgNPs were evaluated on eight cancer cell lines. Further cytotoxic studies were performed in gynecological cancer cell lines from cervical (HeLa) and breast (MDA-MB-231 and MCF7) cancer. In both cases, the half maximal inhibitory concentration (IC50) of AgNPs produced the formation of reactive oxygen species (ROS) after 24 h of incubation, but it was not statistically significant compared with untreated cells. However, HeLa, MDA-MB-231, and MCF7 cells treated with the maximal IC of AgNPs induced the formation of ROS either at 12 or 24 h of incubation. Genotoxicity achieved by comet assay in HeLa, MDA-MB-231, and MCF7 cells revealed that exposure to IC50 of AgNPs does not induced noticeable DNA damage in the cells. However, the IC of AgNPs provoked severe DNA damage after 12 and 24 h of exposure. We conclude that, Argovit (polyvinylpyrrolidone-coated AgNPs) induce a cytotoxic effect in a time and dose-dependent manner in all the eight cancer cell lines tested. Nevertheless, the genotoxic effect is mainly restricted by the concentration effect. The results contribute to explore new therapeutic applications of AgNPs for malignances in murine models and to study in deep the cytotoxic and genotoxic effects of AgNPs in healthy cells at the surrounding tissue of the neoplasia.