Antitumoral photoinduced effects of crude extract, fractions, and naphthoquinones from Sinningia magnifica (Otto & A. Dietr.) Wiehler (Gesneriaceae) in a bioguided study.

Photodynamic therapy (PDT) has been used for various purposes, including as an antitumor resource in a noninvasive therapy with minimal side effects. Sinningia magnifica (Otto & A. Dietr.) Wiehler is a rupicolous plant found in rock crevices in Brazilian tropical forests. Initial studies indicate the presence of phenolic glycosides and anthraquinones in species of the genus Sinningia (Generiaceae family). It is known that anthraquinones are natural photosensitizers with potential PDT applications. This led us to investigate the potential compounds of S. magnifica for use as a natural photosensitizer against the melanoma (SK-MEL-103) and the prostate cancer (PC-3) cell lines in a bioguided study. Our results showed that singlet oxygen production by the 1,3-DPBF photodegradation assay greatly increased in the presence of crude extract and fractions. The biological activity evaluation showed photodynamic action against melanoma cell line SK-MEL-103 and prostate cell line PC-3. These results suggest the presence of potential photosensitizing substances, as demonstrated in this in vitro antitumor PDT study by the naphthoquinones Dunniol and 7-hydroxy-6-methoxy-α-dunnione for the first time. Naphthoquinones, anthraquinones and phenolic compounds were identified in the crude extract by UHPLC-MS/MS analysis, motivating us to continue with the bioguided phytochemical study aiming to discover more photochemically bioactive substances in Gesneriaceae plants.

Compostos coordenados híbridos de platina no tratamento do câncer / Platinum hybrid coordinated compounds in cancertreatment

O câncer, ou neoplasia, é uma doença caracterizada pela propagação descontrolada de formas anormais das próprias células corporais e corresponde à segunda doença que mais causa mortes no mundo. A história da platina no tratamento do câncer teve início com a descoberta da sua atividade, em 1965, com a aprovação para uso clínico acontecendo apenas após 10 anos. Atualmente, os fármacos com platina estão entre os mais bem sucedidos agentes anticancerígenos, onde se destacam cisplatina (1), carboplatina (2) e oxaliplatina (3). Seus mecanismos de ação são similares: estes fármacos formam adutos com o DNA, impedindo a sua síntese e reparo, levando à morte celular. Contudo, os efeitos adversos desencadeados pelo tratamento e o desenvolvimento de resistência ao medicamento têm limitado suas aplicações. Uma das principais estratégias para a diminuição de tais efeitos consiste em alterar a estrutura destas moléculas, levando à formação de compostos híbridos, que se caracterizam pela presença de pelo menos dois fragmentos funcionais distintos em uma mesma molécula e podem apresentar maior espectro de atividade antitumoral. Dentre as alterações mais comuns encontram-se a modificação da solubilidade, através da inserção de grupos abandonadores mais ou menos hidrofóbicos e a introdução de ligantes com atividade biológica própria. Dessa forma, esta revisão visa verificar os avanços mais recentes na síntese de compostos híbridos de platina, bem como as melhorias na atividade anticâncer dos novos compostos platinados...

Cancer, or neoplasm, is a disease characterized by the uncontrolled propagation of abnormal cells of the body and is the second leading death-causing disease. The history of platinum in cancer treatment goes back to the discovery of its activity in 1965 and its approval for clinical use just 10 years later. Some of the most successful anticancer agents are Pt-based chemotherapeutics, among which cisplatin (1), carboplatin (2), and oxaliplatin (3) stand out. They have similar mechanisms of action: they form adducts with DNA, preventing its synthesis and repair and leading to cell death. However, adverse effects triggered by treatment and the development of resistance to these drugs have limited their application. One of the most important strategies to reduce such effects is to carry out structural modifications of these molecules, leading to hybrid compounds that are characterized by the presence of at least two distinct functional fragments on the same molecule and can exhibit a broader antitumor activity spectrum. Among the most typical modifications are changes to the solubility pattern, created by the insertion of leaving groups with high or low hydrophobicity, and the introduction of biologically active ligands as non-leaving groups. The purpose of these strategies is to obtain compounds capable of reducing systemic toxicity and/or overcoming acquired resistance factors to cisplatin. Therefore, the aim of this review is to discuss the most recent advances in the synthesis of hybrid platinum compounds, as well as improvements in the anticancer activity of Pt-compounds...