Examinando por Autor "Werner, Enrique"

Mostrando 1 - 4 de 4
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    Antioxidant and Anti-Proliferative Activity of Essential Oil and Main Components from Leaves of Aloysia polystachya Harvested in Central Chile
    (MDPI, 2021) Catalina Moller, Alejandra; Parra, Carol; Said, Bastian; Werner, Enrique; Flores, Susana; Villena, Joan; Russo, Alessandra; Caro, Nelson; Montenegro, Iván; Madrid, Alejandro
    The aim of this study was to determine, first, the chemical composition of Aloysia polystachya (Griseb) Moldenke essential oil, from leaves harvested in central Chile; and second, its antioxidant and cytotoxic activity. Eight compounds were identified via gas chromatography–mass spectrometry (GC–MS) analyses, with the most representative being R-carvone (91.03%), R-limonene (4.10%), and dihydrocarvone (1.07%). For Aloysia polystachya essential oil, antioxidant assays (2,2-diphenyl1-picrylhydrazyl (DPPH), H2O2, ferric reducing antioxidant power (FRAP), and total reactive antioxidant potential (TRAP)) showed good antioxidant activity compared to commercial antioxidant controls; and anti-proliferative assays against three human cancer cell lines (colon, HT-29; prostate, PC-3; and breast, MCF-7) determined an IC50 of 5.85, 6.74, and 9.53 μg/mL, and selectivity indices of 4.75, 4.12, and 2.92 for HT-29, PC-3, and MCF-7, respectively. We also report on assays with CCD 841 CoN (colon epithelial). Overall, results from this study may represent, in the near future, developments for natural-based cancer treatments.
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    Chemical Analysis and In Vitro Bioactivity of Essential Oil of Laurelia sempervirens and Safrole Derivatives against Oomycete Fish Pathogens
    (MDPI, 2021) Madrid, Alejandro; Lizeth Morales, Ana; Saffirio, Valentina; Cuellar, Mauricio A.; Werner, Enrique; Said, Bastián; Godoy, Patricio; Caro, Nelson; Melo, Mirna; Montenegro, Iván
    In this study, the essential oil (EO) from Laurelia sempervirens was analyzed by GC/MS and safrole (1) was identified as the major metabolite 1, was subjected to direct reactions on the oxygenated groups in the aromatic ring and in the side chain, and eight compounds (4 to 12) were obtained by the process. EO and compounds 4–12 were subjected to biological assays on 24 strains of the genus Saprolegnia, specifically of the species 12 S. parasitica and 12 S. australis. EO showed a significant effect against Saprolegnia strains. Compound 6 presents the highest activity against two resistant strains, with minimum inhibitory concentration (MIC) and minimum oomyceticidal concentration (MOC) values of 25 to 100 and 75 to 125 μg/mL, respectively. The results show that compound 6 exhibited superior activities compared to the commercial controls bronopol and azoxystrobin used to combat these pathogens.
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    Chemical Composition, Antioxidant and Anticancer Activities of Leptocarpha rivularis DC Flower Extracts
    (MDPI, 2021) Montenegro, Jorge; Moreira, Jorge; Ramirez, Ingrid; Dorta, Fernando; Sánchez, Elizabeth; Alfaro, Juan Felipe; Valenzuela, Manuel; Jara-Gutiérrez, Carlos; Muñoz, Ociel; Alvear, Matías; Werner, Enrique; Madrid, Alejandro; Villena, Joan; Seeger, Michael
    An evaluation of antioxidant and anticancer activity was screened in Leptocarpha rivularis DC flower extracts using four solvents (n-hexane (Hex), dichloromethane (DCM), ethyl acetate (AcOEt), and ethanol (EtOH)). Extracts were compared for total extract flavonoids and phenol contents, antioxidant activity (2,2-diphenyl-1-picryl-hydrazyl-hydrate (DPPH), ferric reducing antioxidant potential (FRAP), total reactive antioxidant properties (TRAP) and oxygen radical absorbance capacity (ORAC)) across a determined value of reduced/oxidized glutathione (GSH/GSSG), and cell viability (the sulforhodamine B (SRB) assay). The most active extracts were analyzed by chromatographic analysis (GC/MS) and tested for apoptotic pathways. Extracts from Hex, DCM and AcOEt reduced cell viability, caused changes in cell morphology, affected mitochondrial membrane permeability, and induced caspase activation in tumor cell lines HT-29, PC-3, and MCF-7. These effects were generally less pronounced in the HEK-293 cell line (nontumor cells), indicating clear selectivity towards tumor cell lines. We attribute likely extract activity to the presence of sesquiterpene lactones, in combination with other components like steroids and flavonoids.
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    Ultrasound assisted synthesis and cytotoxicity evaluation of known 2′ ,4′ -dihydroxychalcone derivatives against cancer cell lines
    (Elsevier, 2021) Villena, Joan; Montenegro, Ivan; Said, Bastian; Werner, Enrique; Flores, Susana; Madrid, Alejandro
    This work reports on the development of an efficient and ecofriendly ultrasound assisted method for the high yield synthesis (70.0–94.0%) of eighteen oxyalkylated derivatives of 2′ ,4′ -dihydroxychalcone. Synthesized compounds were subjected to in vitro biological assays against HT-29 (colorectal), MCF-7 (breast), and PC-3 (prostate) human tumor cell lines, these cell lines are among the ten most aggressive malignancies diagnosed in the world. Cytotoxicity evaluations showed that four of the synthesized compounds exhibited moderate to very high toxic activity against MCF-7 (IC50 = 8.4–34.3 μM) and PC-3 (IC50 = 9.3–29.4 μM) – comparable to 5-fluorouracil (IC50 16.4–22.3 μM). The same compounds only showed moderate activity against HT-29 (IC50 15.3–36.3 μM), closer to daunorubicin (IC50 15.1 μM). Next, although selectivity index (SI) of compounds was weak, compound 18 exhibited a remarkable and selective cytotoxic activity (5.8–10.57) against cancer cells. Outside of these, most compounds significantly reduced cell survival, increased reactive oxygen species (ROS) and caspase activity, and decreased mitochondrial membrane permeability. In this sense, a portion of antiproliferative activity is due to apoptosis. Notwithstanding, due to its remarkable response, chalcone 18 may be a potential alternative as a chemotherapeutic anti-carcinogen.