RESUMO
The antioxidant activities of Dangcong tea aqueous extracts against DPPH and ABTS free radicals were evaluated using spectrometric methods. The results show that Dangcong tea aqueous extracts could effectively and rapidly inhibited the formation of ABTS and DPPH free radicals in a dose- and time-dependent manner, indicating the potent antioxidant activities of Dangcong tea aqueous extracts under both hydrophilic and hydrophobic conditions. In the optimized systems, the IC50 values of Baiye (I, II) and Fenghuang (III, IV) Dangcong teas against ABTS free radical were 26.9, 25.5, 28.0 and 31.7 microg x mL(-1), respectively, which were significantly lower than that of Trolox, the positive control (85.2 microg x mL(-1)), indicating the higher antioxidant activities of Dangcong teas. For DPPH free radical, the IC50 values for the Dangcong teas (I-IV) were 49.8, 41.6, 47.3 and 64.5 microg x mL(-1), respectively. Taken together, our results suggest the potential applications of Dangcong tea as functional food.
Assuntos
Sequestradores de Radicais Livres/química , Extratos Vegetais/química , Chá/química , Benzotiazóis , Compostos de Bifenilo , Radicais Livres , Oxirredução , Picratos , Ácidos SulfônicosRESUMO
A simple method for fabrication of sialic acid surface-decorated selenium nanoparticles (SA-Se-NPs) with enhanced cancer-targeting and cell-penetrating abilities has been demonstrated in the present study. Monodisperse and homogeneous spherical SA-Se-NPs with striking stability were prepared under the optimized conditions. SA surface decoration significantly increased the cellular uptake and cytotoxicity of Se-NPs in HeLa human cervical carcinoma cells. Treatments of SA-Se-NPs induced dose-dependent apoptosis in HeLa cells, as evidenced by increase in sub-G1 cell populations, nuclear condensation and formation of apoptotic bodies. Further investigation on molecular mechanisms reveals that SA-Se-NPs triggered cancer cell apoptosis through activation of caspase-3 and subsequent cleavage of PARP.