Browsing by Author "Gil-Izquierdo, Angel"
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- HPLC-PAD-atmospheric pressure chemical ionization-MS metabolite profiling of cytotoxic carotenoids from the echinoderm Marthasterias glacialis (spiny sea-star)Publication . Ferreres, Federico; Pereira, David M.; Gil-Izquierdo, Angel; Valentão, Patrícia; Botelho, João; Mouga, Teresa; Andrade, Paula B.An HPLC-PAD-atmospheric pressure chemical ionization-MS metabolite profiling analysis was conducted on the marine echinoderm Marthasterias glacialis (spiny sea-star). Bio-guided purification of the methanolic extract led to the isolation of several carotenoids, namely zeaxanthin, astaxanthin and lutein. These compounds were characterized using both UV–Vis characteristics and MS spectra interpretation. No previous works addressed the MS analysis of carotenoids present in this organism. The purified carotenoid fraction displayed a strong cell proliferation inhibition against rat basophilic leukemia RBL-2H3 (IC25 5 268 mg/mL) cancer cell line. Against healthy V79 (rat lung fibroblasts (IC25 5411 mg/mL)) cell line, however, toxicity was lower, as it is desired for anti-cancer molecules. This study suggests that M. glacialis may constitute a good source of bioactive compounds that can be used as lead compounds for the pharmaceutical industry.
- Phlorotannin Extracts from Fucales Characterized by HPLC-DAD-ESI-MSn: Approaches to Hyaluronidase Inhibitory Capacity and Antioxidant PropertiesPublication . Ferreres, Federico; Lopes, Graciliana; Gil-Izquierdo, Angel; Andrade, Paula; Sousa, Carla; Mouga, Teresa; Valentão, PatríciaPurified phlorotannin extracts from four brown seaweeds (Cystoseira nodicaulis (Withering) M. Roberts, Cystoseira tamariscifolia (Hudson) Papenfuss, Cystoseira usneoides (Linnaeus) M. Roberts and Fucus spiralis Linnaeus), were characterized by HPLC-DAD-ESI-MSn . Fucophloroethol, fucodiphloroethol, fucotriphloroethol, 7-phloroeckol, phlorofucofuroeckol and bieckol/dieckol were identified. The antioxidant activity and the hyaluronidase (HAase) inhibitory capacity exhibited by the extracts were also assessed. A correlation between the extracts activity and their chemical composition was established. F. spiralis, the species presenting higher molecular weight phlorotannins, generally displayed the strongest lipid peroxidation inhibitory activity (IC50 = 2.32 mg/mL dry weight) and the strongest HAase inhibitory capacity (IC50 = 0.73 mg/mL dry weight). As for superoxide radical scavenging, C. nodicaulis was the most efficient species (IC50 = 0.93 mg/mL dry weight), followed by F. spiralis (IC50 = 1.30 mg/mL dry weight). These results show that purified phlorotannin extracts have potent capabilities for preventing and slowing down the skin aging process, which is mainly associated with free radical damage and with the reduction of hyaluronic acid concentration, characteristic of the process.