Water extract of mangosteen suppresses H2O2-induced endothelial apoptosis by inhibiting oxidative stress

Excessive production of reactive oxygen species (ROS) is a major cause of endothelial apoptosis. Mangosteenextract has been shown to possess antioxidant properties. Mangosteen is commonly extracted either with semi-polarsolvent, yielding virtually pure α-mangostin, or with water, yielding a low α-mangostin concentration but includinga wide variety of other polyphenols present in the fruit. However, the effect of a water extract of mangosteen(ME) on ROS induced cell death is not yet known. This study evaluated whether ME suppresses H2O2-inducedendothelial cell death and ROS production in human endothelial cell lines. The concentrations of ME and H2O2were determined by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay. IntracellularROS levels were determined by 2', 7' dichlorodihydrofluorescein diacetate assay, and cell death rates by MTT andTerminal deoxynucleotidyl transferase dUTP Nick-End Labeling assays. mitogen-activated protein kinase (MAPK)and apoptotic proteins were analyzed by western blot. Results showed that ME concentrations of 1, 5, and 10 µg/mlwere non-toxic. ME significantly attenuated ROS formation and cell death, both in a dose-dependent manner. MEalso reduced phosphorylation of p38 MAPK as well as cleavage of caspase 3 and poly(ADP-ribose) polymerase-1.In summary, ME demonstrates anti-apoptotic effects against H2O2-induced endothelial cell death by inhibiting ROSformation and suppressing p38 MAPK.

Cytotoxicity and apoptosis of ovarian and breast cancer cell lines induced by OVS1 monoclonal antibody and paclitaxel.

OVS1 monoclonal antibody (MAb) produced against ovarian cancer is currently used to identify mucinous cystadenocarcinoma antigen as a tumor marker secreted in serum. The potential of OVS1 MAb in ovarian cancer treatment was studied by evaluating the induction of cytotoxicity and apoptosis of SKOV3 ovarian cancer and BT549 breast cancer cell lines induced by OVS1. Paclitaxel, an antitumor drug, was used as positive control and applied as a combined drug together with OVS1 MAb. OVS1 MAb and paclitaxel were found by MTT assay to induce cytotoxicity against both cell lines. The ED50 of OVS1 MAb were 26.25 and 25.00 microg/ml and of paclitaxel were 21.88 and 9.20 nM against SKOV3 and BT549 cell lines, respectively. The quantitative amount of cells determined by fluorimetric assay was correlated to the results of the MTT assay. The combined application of OVS1 MAb and paclitaxel on these two cell lines resulted in a greater cytotoxicity than observed by either agent alone. OVS1 MAb and paclitaxel applied against both cell lines induced the morphological changes of apoptotic cell death at 24 hours visualized by two color fluorescence dyes, Ho33342 and propidium iodide. Combination of the two substances enhanced the rate of apoptosis compared to either OVS1 MAb or paclitaxel given alone. DNA fragmentation was detected in an agarose gel electrophoresis after treating cells with OVS1 MAb and paclitaxel at 24 hours. These findings on the induction of cytotoxicity and apoptosis by OVS1 MAb on cancer cell lines have implications on the potential application of OVS1 MAb for clinical therapy.