164 research outputs found

    Curcuminoid Binding to Embryonal Carcinoma Cells: Reductive Metabolism, Induction of Apoptosis, Senescence, and Inhibition of Cell Proliferation

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    Curcumin preparations typically contain a mixture of polyphenols, collectively referred to as curcuminoids. In addition to the primary component curcumin, they also contain smaller amounts of the co-extracted derivatives demethoxycurcumin and bisdemethoxycurcumin. Curcuminoids can be differentially solubilized in serum, which allows for the systematic analysis of concentration-dependent cellular binding, biological effects, and metabolism. Technical grade curcumin was solubilized in fetal calf serum by two alternative methods yielding saturated preparations containing either predominantly curcumin (60%) or bisdemethoxycurcumin (55%). Continual exposure of NT2/D1 cells for 4–6 days to either preparation in cell culture media reduced cell division (1–5 µM), induced senescence (6–7 µM) or comprehensive cell death (8–10 µM) in a concentration-dependent manner. Some of these effects could also be elicited in cells transiently exposed to higher concentrations of curcuminoids (47 µM) for 0.5–4 h. Curcuminoids induced apoptosis by generalized activation of caspases but without nucleosomal fragmentation. The equilibrium binding of serum-solubilized curcuminoids to NT2/D1 cells incubated with increasing amounts of curcuminoid-saturated serum occurred with apparent overall dissociation constants in the 6–10 µM range. However, the presence of excess free serum decreased cellular binding in a hyperbolic manner. Cellular binding was overwhelmingly associated with membrane fractions and bound curcuminoids were metabolized in NT2/D1 cells via a previously unidentified reduction pathway. Both the binding affinities for curcuminoids and their reductive metabolic pathways varied in other cell lines. These results suggest that curcuminoids interact with cellular binding sites, thereby activating signal transduction pathways that initiate a variety of biological responses. The dose-dependent effects of these responses further imply that distinct cellular pathways are sequentially activated and that this activation is dependent on the affinity of curcuminoids for the respective binding sites. Defined serum-solubilized curcuminoids used in cell culture media are thus suitable for further investigating the differential activation of signal transduction pathways

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    BetaSweet carrot extracts have antioxidant activity and in vitro antiproliferative effects against breast cancer cells

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    Fruits and vegetables have long been studied for their potential roles in reducing certain cancer risks. Herein, lyophilized BetaSweet carrots were extracted with hexane, methanol, and water and their chemical constituents were identified by UPLC-QTOF-HR-MS. Methanol extracts exhibited significantly higher radical scavenging activity compared with hexane and water extracts. Hexane extracts showed significantly higher (88.4%) inhibition of breast cancer cells proliferation after 24 h at 100 µg/mL, followed by water and methanol extracts, likely due to the presence of polyacetylenes. Cells treated with hexane extracts showed the highest cytochrome-c release, indicating induction of apoptosis, as supported by DNA fragmentation and Bax2 and bcl2 expression and confirmed by staining with propidium iodide and acridine orange. The methanol extract showed the highest antioxidant activity and was purified to obtain cyanidin-3-2″-xylosyl-6″-(ferulosyl-glucosyl)-galactoside. In conclusion, BetaSweet carrots exhibits multiple health benefits to use as functional foods
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