In vitro and in vivo antitumor activity of crude extracts obtained from Brazilian Chromobacterium sp. isolates.

Abstract

Natural products produced by microorganisms have been an important source of new substances and lead compounds for pharmaceutical industry. Chromobacterium violaceum is a Gram negative ²-Proteobacteria, abundant in water and soil in tropical and subtropical regions and produce violacein, a pigment that has shown great pharmaceutical potential. Crude extracts of five Brazilian isolates of Chromobacterium sp. were evaluated in in vitro antitumor activity assay with nine human tumor cells. Secondary metabolic profiles were analyzed by liquid chromatography and electrospray ionization mass spectrometry resulting in the identification of violacein in all extracts, whereas FK228 was detected only in EtCE 308 and EtCE 592 extracts. AcCE and EtCE 310 extracts showed selectivity for NCI-ADR/RES in the in vitro assay and were evaluated in vivo in the solid Ehrlich tumor model resulting in 50.3% and 54.6% growth inhibition, respectively. The crude extracts of Chromobacterium sp. isolates showed potential and selective antitumor activities for certain human tumor cells, making them a potential source of lead compounds. Furthermore, the results suggest that other compounds, in addition to violacein, deoxyviolacein and FK228, can be involved in the antitumor effect observed. (AU)