Violacein Cytotoxicity and Induction of Apoptosis in V79 Cells

Abstract

Violacein, a pigment produced by Chromobacterium violaceum, is reported to be a potential drug for the treatment of Chagas' disease. Violacein is also effective against leukemia and lymphoma cells in culture (IC50 10(-8) M). Changes in the nuclear acid content, 3-(4,5-dimethylthiazole-2-yl)-2,5-biphenyl tetrazolium bromide reduction and neutral red uptake in these cells were used to evaluate the cytotoxicity of violacein in V79 Chinese hamster (M-8) fibroblasts. Violacein was highly cytotoxic to V79 fibroblasts (IC50 5-12 microM). Using the TUNEL method and the Feulgen reaction coupled to image analysis, violacein (5 and 10 microM) was found to trigger apoptosis but not necrosis in V79 cells. The morphological changes seen in the nuclei of these cells included chromatin condensation and a decrease in deoxyribonucleic acid content. These results demonstrating that violacein induces apoptosis in V79 cells strengthen its potential as a therapeutic agent.

Cytotoxicity and potential antiviral evaluation of violacein produced by Chromobacterium violaceum

“…Preliminary studies had already demonstrated that violacein presents cytotoxicity to V79 fibroblasts (CC 50 = 7 µM; MTT assay) (Melo et al 2000).This cytotoxicity was also verified with the cell lines used in this study, and Violacein showed a concentration-response relationship since the cytotoxicity increased gradually with the increase of its concentration as shown by the tested methodologies ( Figure).…”

“…as an indicator of acute toxic effects in vivo) and are also important for designing more in depth in vitro studies (Eisenbrand et al 2002). These data will be useful for a better understanding of other biological activities attributed to violacein, such as antibacterial, antitumoral and anti-Trypanosoma cruzi activities (Melo et al 2000, Duran & Menck 2001. One strategy used to improve biological activity is the incorporation of active substances into liposomes which offer a substancial improvement in the therapeutic indices of the molecules entrapped in them (Gulati et al 1998).…”

“…The most notable characteristic of C. violaceum is the production of the chemically well characterized pigment named violacein (Bromberg & Duran 2001). Previous studies indicated antibiotic and antichagasic (Duran & Menck 2001), antitumoral (Melo et al 2000), and antileishmanial (Leon et al 2001) activities of violacein.…”

The Violacein Biosynthetic Enzyme VioE Shares a Fold with Lipoprotein Transporter Proteins

“…1) is a purple pigment that gives tropical bacterium Chromobacterium violaceum its characteristic coloring (1-5). Violacein 5 has potential medical applications as an antibacterial (6 -8), anti-tryptanocidal (8 -10), anti-ulcerogenic (11), and anti-cancer drug (8,(12)(13)(14)(15)(16)(17). The molecule, made of L-tryptophan and molecular oxygen (18 -21), was originally thought to be synthesized by the action of just four enzymes VioABCD (22, 23), but an additional open reading frame (24), also in the operon, was shown to encode the enzyme VioE (25, 26).…”

Potencial antiviral da quercetina sobre o parvovírus canino

“…Esse teste também é importante para verificar a toxicidade de novos compostos nos estágios iniciais de desenvolvimento de fármacos (Putnam et al, 2002), pois o equilíbrio entre os efeitos farmacológicos e toxicológicos de um composto é um requisito essencial para sua aplicabilidade como futuro agente terapêutico (Melo et al, 2002).…”