Navegando por Autor "Paula, Ana Cláudia Chagas de"

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    Phenylpropanoid-based sulfonamide promotes cyclin D1 and cyclin E downregulation and induces cell cycle arrest at G1/S transition in estrogen positive MCF-7 cell line.
    (2019) Barbosa, Helloana Azevedo; Silva, Guilherme Álvaro Ferreira da; Silva, Carolina Faria; Souza, Thiago Belarmino de; Dias, Danielle Ferreira; Paula, Ana Cláudia Chagas de; Ionta, Marisa; Carvalho, Diogo Teixeira
    Cancer is one of the most critical problems of public health in the world and one of the main challenges for medicine. Different biological effects have been reported for sulfonamide-based compounds including antibacterial, antifungal, and antitumor activities. Herein, a series of phenylpropanoid-based sulfonamides (4a, 4a′, 4b, 4b′, 5a, 5a′, 5b and 5b′) were synthesized and their cytotoxic activity was evaluated against four cell lines derived from human tumours (A549 – lung, MCF-7 – breast, Hep G2 - hepatocellular carcinoma, and HT-144-melanoma). Cell viability was significantly reduced in the MCF-7 cell line when compounds 4b, 4b′ and 5a were used; IC50 values were lower than those found for their precursors (eugenol and dihydroeugenol) and sulfanilamide. We observed that 4b induced cell cycle arrest at G1/S transition. This is probably due to its ability to reduce cyclin D1 and cyclin E expression. Moreover, 4b also induced apoptosis in MCF-7 cells as demonstrated by an increase in the cell population positive for annexin V in treated cultures in comparison to the control group. Taken together, the data showed that 4b is a promising antitumor agent and it should be considered for further in vivo studies.
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    Uptake and metabolism of the Cyanobacterial Hepatotoxin Microcystin-RR by Spirodela intermedia from Brazil.
    (2009) Ferreira, Tanare Cambraia Ribeiro; Freitas, Tália Carvalho de; Paula, Ana Cláudia Chagas de; Jardim, Fernando Antônio; Guarda, Vera Lúcia de Miranda
    Spirodela intermedia was exposed to low (10 µg L-1) and high concentration (100 µg L-1) of microcystin-RR (Arginin-Arginin) over aperiod of two weeks. Depuration in the water phase, as weIl as uptake in the plant was determined using HPLC with photodiode array (PDA) detection. After the toxin uptake, metabolism of microcystin-RR occuored resulting in the formation of a glutathione conjugate. This conjugate was further processed yielding in a cysteine conjugate, a weIl known breakdown product in the biotransformation pathway of microcystins. The results indicate the uptake, accumulation and metabolism of microcystin-RR in a surface floating aquatic plant and raise the possibilities, to use these plants within water purification or toxin removal. Further implication on aquatic ecosystem and the transfer of toxin in the food web might occur and needs more investigation.