Browsing by Author "Silva, Viviana"
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- 1,2-dihydroxyxanthone: effect on A375-C5 melanoma cell growth associated with interference with THP-1 human macrophage activityPublication . Silva, Viviana; Cerqueira, Fátima; Nazareth, Nair; Medeiros, R.; Sarmento, Amélia; Sousa, Emília; Pinto, MadalenaXanthones have been suggested as prospective candidates for cancer treatment. 1,2- dihydroxyxanthone (1,2-DHX) is known to interfere with the growth of several cancer cell lines. We investigated the effects of 1,2-DHX on the growth of the A375-C5 melanoma cell line and THP-1 human macrophage activity. 1,2-DHX showed a moderate growth inhibition of A375-C5 melanoma cells (concentration that causes a 50% inhibition of cell growth (GI50) = 55.0 ±2.3 µM), but strongly interfered with THP-1 human macrophage activity. Supernatants from lipopolysaccharide (LPS)-stimulated THP-1 macrophage cultures exposed to 1,2-DHX significantly increased growth inhibition of A375-C5 cells, when compared to supernatants from untreated LPS-stimulated macrophages or to direct treatment with 1,2-DHX only. 1,2-DHX decreased THP-1 secretion of interleukin-1β (IL-1β) and interleukin-10 (IL-10), but stimulated tumor necrosis factor-α (TNF-α) and transforming growth factor-β1 (TGF-β1) production. This xanthone also inhibited nitric oxide (NO) production by RAW 264.7 murine macrophages, possibly through inhibition of inducible NO synthase production. In conclusion, these findings suggest a potential impact of 1,2-DHX in melanoma treatment, not only due to a direct effect on cancer cells but also by modulation of macrophage activity.
- Functional foods and phytotherapeutic: use as agents of plant development and prevention of public healthPublication . Silva, Viviana; Coutinho, Filipe; Oliveira, Marta Isabel; Iglésias, Raúl; García Estevez, José; Ferreira da Vinha, AnaThe current way of life may cause the increase of chronic degenerative diseases, whose treatment is not always possible with pharmacological medication. The Diet Therapy and Phytotherapy are on the rise, associated with functional foods phytotherapeutic action. The antioxidant action of bioactive compounds depends on their chemical structures and their concentrations in food. The main objective of this study was to characterize and evaluate fourteen plants of green leaf of national culture in its physical‐chemistry, levels of antioxidant compounds and synergistic effects between them, measured by the method of capture of free radical DPPH. The chemical parameters studied were water content, pH, ascorbic acid content and also total carotenoids.