RESUMEN
Bioassay-guided fractionation of dichloromethane extract from Athenaea velutina leaves led to the isolation of three withanolides, all being reported for the first time in this species. They were identified as withacnistin (1), withacnistin acetate (2) and a new withanolide, designated as withalutin (3). The structures were established by spectral data analysis, including MS, 1D and 2D NMR. In addition, in silico ADMET studies were employed to understand the pharmacokinetic properties of these withanolides. The withanolides isolated from A. velutina reduced cancer cell viability with IC50 values ranging from 1.52 to 5.39 µM. In silico prediction revealed that withanolides have good gastrointestinal absorption or oral bioavailability properties; and are not likely to be mutagenic or hepatotoxic. These findings revealed that A. velutina is an important source of cytotoxic withanolides.
Asunto(s)
Antineoplásicos , Solanaceae , Witanólidos , Witanólidos/química , Solanaceae/química , Lactonas/análisis , Hojas de la Planta/química , Antineoplásicos/análisisRESUMEN
Athenaea velutina is a promising Brazilian shrub with cytotoxic and antimigratory properties against cancer cells. However, the mechanism of induction of cancer cell death and the compounds involved remain unknown. To ascertain these bioactive compounds, bioassay-guided fractionation was performed, alongside the appropriate in vitro tests. A withanolide-rich fraction (FAv_5) from the dichloromethane extract increased cytotoxic activity by 1.5-fold (IC50 = 2.1 µg/mL). Fourteen withanolide steroids were tentatively identified for the first time for this species by mass spectrometry coupled to liquid chromatography (LC MS/MS), including withanolide A, aurelianolide A, and aurelianolide B. FAv_5 significantly decreased cell proliferation, migration, and invasion with a selectivity index greater than 8 for B16F10 cells. Furthermore, flow cytometry with annexin V fluorescein isothiocyanate/propidium iodide (V-FITC/PI) staining showed FAv_5 to promote cell cycle arrest at the G0/G1-phase as well as apoptotic cell death. Overall, these findings highlight A. velutina as a source of withanolide-steroids that inhibit cancer cell proliferation through apoptosis and cell cycle blockade mechanisms. Details on the geographic distribution of A. velutina and species conservation strategies have also been highlighted.
Asunto(s)
Melanoma , Witanólidos , Apoptosis , Ciclo Celular , Puntos de Control del Ciclo Celular , Línea Celular Tumoral , Proliferación Celular , Humanos , Extractos Vegetales/química , Extractos Vegetales/farmacología , Espectrometría de Masas en Tándem , Witanólidos/farmacologíaRESUMEN
Plant biodiversity is a source of potential natural products for the treatment of many diseases. One of the ways of discovering new drugs is through the cytotoxic screening of extract libraries. The present study evaluated 196 extracts prepared by maceration of Brazilian Atlantic Forest trees with organic solvents and distilled water for cytotoxic and antimetastatic activity. The MTT assay was used to screen the extract activity in MCF-7, HepG2 and B16F10 cancer cells. The highest cytotoxic extract had antimetastatic activity, as determined in in vitro assays and melanoma murine model. The organic extract of the leaves of Athenaea velutina (EAv) significantly inhibited migration, adhesion, invasion and cell colony formation in B16F10 cells. The phenolic compounds and flavonoids in EAv were identified for the first time, using flow injection with electrospray negative ionization-ion trap tandem mass spectrometry analysis (FIA-ESI-IT-MSn ). EAv markedly suppressed the development of pulmonary melanomas following the intravenous injection of melanoma cells to C57BL/6 mice. Stereological analysis of the spleen cross-sections showed enlargement of the red pulp area after EAv treatment, which indicated the activation of the haematopoietic system. The treatment of melanoma-bearing mice with EAv did not result in liver damage. In conclusion, these findings suggest that A velutina is a source of natural products with potent antimetastatic activity.