Protective effect of Mangifera indica L. polyphenols on human T lymphocytes against activation-induced cell death

Time-course regulation of survival pathways by epicatechin on HepG2 cells

“…In agreement with these findings, slight effects of this flavonoid on cell viability in human hepatic [29], prostatic [11], colonic [30,31], T lymphocytic [32] and oral cavity [33] cells have also been reported. Importantly, although this flavonoid is the least toxic when compared to other polyphenols in tea, its cytotoxic effects are more pronounced in cancer cells than in the normal counterparts [33], and it has also been shown that the response of the cancer cells to a catechin treatment can also depend on the length of the exposure [34].…”

“…Epicatechin possesses a high antioxidant activity, and it has been demonstrated that it protects cells from oxidative insults by preventing cell death and free radical formation in the presence of metals [5,6] or t-BOOH [35], showing a cytoprotective activity in hepatic cells [10,36]. Moreover, treatment of cells with epicatechin alone resulted in unchanged or slightly decreased levels of ROS formation after different incubation times [9,11,32]. Our study shows a decrease of ROS production by epicatechin at short incubation times (up to 240 min), recovering then to control values after 18 h of incubation (Table 1).…”

Cytotoxic effect of Pouteria torta leaf extracts on human oral and breast carcinomas cell lines

“…The anti-oxidative, protective effect of these compounds against cell death has already been reported elsewhere. [24] It is speculated that by increasing the dosis, the concentration of polyphenols in the sample reach a level high enough to scavenge free radical and thus protect cells from toxic agents. Such hypothesis still awaits testing.…”

Thymoquinone, the active ingredient ofNigella sativaseeds, enhances survival and activity of antigen-specific CD8-positive T cellsin vitro

“…32 Several studies have shown that antioxidants (e,g., vitamin E, N-acetylcysteine, Mangifera indica polyphenol) prevent activation-induced cell death (AICD). [33][34][35] Other studies have examined the effects of antioxidants on TCRstimulated death of T cells, and show that exposure to antioxidants inhibits AICD of T cells in cell lines and in primary T cells. 36 Although the stimulatory effects of the low concentrations of TQ on T-cell survival and function could be attributed to different mechanisms, one could be its antioxidant effect.…”